Several reports have shown that less aggressive patterns of diagnostic activity and care are provided to elderly breast carcinoma patients. We sought to investigate whether differences in the management of older women with breast cancer are associated with survival.In an observational study using a population-based clinical breast cancer register of one health-care region in Sweden, we identified 9,059 women aged 50–84 y diagnosed with primary breast cancer between 1992 and 2002. The 5-y relative survival ratio was estimated for patients classified by age group, diagnostic activity, tumor characteristics, and treatment. The 5-y relative survival for breast cancer patients was lower (up to 13%) in women 70–84 y of age compared to women aged 50–69 y, and the difference was most pronounced in stage IIB–III and in the unstaged. Significant differences in disease management were found, as older women had larger tumors, had fewer nodes examined, and did not receive treatment by radiotherapy or by chemotherapy as often as the younger women. Adjustment for diagnostic activity, tumor characteristics, and treatment diminished the relative excess mortality in stages III and in the unstaged, whereas the excess mortality was only marginally affected in stage IIB.Less diagnostic activity, less aggressive treatment, and later diagnosis in older women are associated with poorer survival. The large differences in treatment of older women are difficult to explain by co-morbidity alone. A study from Sweden shows that a lower 5-year relative survival for older women with breast cancer was associated with less diagnostic activity, less aggressive treatment, and later diagnosis. Age should not be a determinant for quality of care in breast cancer. In Sweden, as in many other countries, the population is ageing with a rapidly increasing number of elderly women diagnosed with breast cancer as a consequence. Today about 30% of all breast cancer patients in Sweden are 70 y or older at diagnosis . DespiteThe aim of our study was to investigate whether the differences in management and diagnosis of breast cancer in older women have an effect on the survival. We based our analysis on a population-based clinical database including information on diagnostic activity, tumor characteristics, and treatment.We used a population-based regional breast cancer register for the Uppsala/Örebro health-care region. The register was established in 1992, at the same time as formal written clinical guidelines were issued for the region with the aim to ensure that all women with breast cancer had the same opportunity to receive high-quality care. The region comprises seven counties in Sweden with a total population of about 1.9 million. The register includes individual information about vital status, age, and date of diagnosis, detection mode, tumor-stage, biological tumor characteristics, and primary surgical and oncological treatment. The register includes 97% of all breast cancer patients diagnosed within the region as validated against the mandatory reporting to the Swedish Cancer Registry. The main treatment variables and the staging information have been validated in the register and over 95% agreement was found.Within the Uppsala/Örebro health-care region, all women aged 50–69 y are regularly invited to mammography screening for a low out-of pocket fee. Additional age groups are also invited to screening in some counties, i.e., the age group 40–49 y in five counties, the age group 45–49 y in one county, the age 70 y in one county, and the age group 70–74 y in three counties.Participants were all women with primary breast cancer reported to the Uppsala/Örebro regional breast cancer register from January 1992 to December 2002 12,163 women), with follow-up until December 2003. We excluded 2,169 (17.8%) women who were under 50 y of age and 867 (7.1%) who were older than 84 y. We chose women 50–69 y as a reference group for the elderly, since women 50–69 y were uniformly offered mammography screening and had well-defined treatment recommendations [3 women, The data used in the study are based on quality assurance registers legally required for quality assurance of Swedish health care. The registers are inspected by the Swedish Data Inspection Board.We compared the 5-y relative survival for primary breast cancer patients in different age groups . The relative survival ratio (RSR) is the ratio of the observed survival in the population of interest to the survival that would have been expected had the patients experienced only the age- and period-specific mortality of the general population from which they were drawn [We thereafter stratified the women according to breast cancer stage to study whether the differences in survival between ages were consistent across levels of this variable.diagnostic variables were proliferation status , estrogen receptor status , number of lymph nodes examined , lymph nodal involvement , and tumor size . The proliferation is measured by s-phase and Ki67, or if data on these are missing, by Elston grade. We also examinedtreatment, classified as primary surgical treatment , oncological treatment , and type of treating clinic . For women with advanced disease, we also examined whether they had received any neoadjuvant treatment.To investigate possible differences in management and treatment of younger versus older patients, we used the Fisher's exact test, which tests the independence between age (dichotomized into 50–69 y versus 70–84 y) and the diagnostic and treatment variables. TheWe also constructed a low treatment activity index for women diagnosed with stage I–III breast cancer and for whom stage was not definable. The low treatment activity index was constructed from the evidence-based clinical practice guidelines for breast cancer . Since wLastly, we studied differences in survival between the ages while adjusting for the potential determinants (categorized as explained above) by modeling the excess mortality (RER) using Poisson regression . To asseWe used the analysis of variance to explore the variation of tumor size in different age groups .There were large differences regarding how the breast cancer was detected, i.e., the older the woman, the lower the probability that her cancer was detected by mammography screening . Older wThe unadjusted 5-y relative survival for breast cancer was significantly lower (by up to 13 percentage units) among women aged 75–79, and 80–84 y compared to that for women aged 50–69 y . When weDiagnostic activity and treatment differences were observed between women aged 50–69 y and 70–84 y in all stages.lower proportion of the older women had had ten or more nodes examined. Regarding the treatment characteristics stage by stage, ahigher proportion of the women aged 70–84 y, compared to the women aged 50–69 y, had received mastectomy. As regards the type of surgery delivered, radiotherapy was much less used in the elderly, stage by stage. Chemotherapy was also much less used in the elderly, in agreement with the treatment programs that regularly do not recommend chemotherapy over the age of 69 y. The low treatment activity index created for this study is also considerablyhigher in the older age group, looking at all the stages, although the differences are smaller in stage II. Tamoxifen was, however, more commonly used on the older women compared to the younger, and the difference seems to increase with increasing stage  between age and type of treatment and excess mortality, all within stage III. The RER, comparing women not receiving any surgery to those receiving surgery, was four times higher among the younger compared to the older , whereas the RERs comparing excess mortality among women who received radiation versus no radiation, and chemotherapy versus no chemotherapy were both lower among younger compared to the older women  (data not shown).We found large and clinically relevant absolute survival differences disfavoring women aged 70–84 y as compared to women aged 50–69 y. Due to the Swedish mammography screening policies, the stage distribution was more unfavorable among the older, but an adjustment for stage could only partly explain the survival differences. Looking at relative survival stage by stage, the prognosis was worse in stage IIB and higher among women over 70 y as compared to those 50–69 y. Consistently over the stages we found less diagnostic activity, less use of breast conservation, considerably less use of chemotherapy, higher “low activity index,” and more often treatment in local hospitals in older women. Adjusting for these factors in models largely explained the differences by age group, except for women in stage IIB. Our large population-based register lends further strong support to previous reports  that theWe used a population-based database with high coverage and little misclassification of the variables used in this analysis. Another strength is that relative survival provides a measure of the excess mortality experienced by breast cancer patients, irrespective of whether excess mortality is directly or indirectly attributable to cancer . TherefoAn important explanation for the poorer survival among the elderly was the unfavorable stage distribution due to considerably less mammography screening activity after 70 y and no screening taking place after 74 y. This explanation points to an important health policy issue as the population ages. In many Western countries today, a 70-y-old woman has a life expectancy of 12–16 y.In stages IIB and higher, radiotherapy was less often used in older women, and this could not be explained only by the less frequent use of breast conservation in the elderly. Radiotherapy in itself, although very effective in reducing relapses also among elderly ,12 and Only a very small proportion of the older women received chemotherapy. This is a consequence of the fact that the guidelines during this time period often have suggested upper age limits of 65–70 y for recommending chemotherapy. The evidence base for effectiveness of chemotherapy in the elderly is considered weaker than for younger women and only a few studies of the effect of chemotherapy have included women over 70 y . A few sTamoxifen was widely used in older women in our study. One possible reason for the difference in use (to the disadvantage of the younger patients) is that during the first half of the 1990s, tamoxifen was considered to have a negligible effect in younger patients and was therefore not given to those who received chemotherapy. However, we also found that with higher age, an increasing proportion of women with receptor-negative tumors were treated inappropriately with tamoxifen. A possible interpretation of this finding is that clinicians felt that some treatment activity is warranted in women perceived to have a moderate or high risk of recurrence, but that, in the absence of guidelines regarding chemotherapy, the clinician took the chance that tamoxifen would provide some benefit but little harm.In summary, elderly women were disfavored in several ways: less use of mammography screening, lower diagnostic activity, and lower treatment activity, leading to a lower relative survival. This is a very distressing finding, since around 30% of all breast cancer patients are above the age of 70 y. There is an acute need for more empirical evidence about the effectiveness and tolerability of different treatments in elderly women. Likewise, it is probable that better structured guidelines for elderly women would be a means to improve the situation.Breast cancer is the most common cancer in women in much of the developed world; for example, there are 41,000 new cases in the UK per year. In 2003, 6,869 women were diagnosed with breast cancer in Sweden. Survival has improved greatly; in the past ten years in the UK, the risk of dying of the disease has fallen by one-fifth. The disease is rare in women under 30 years, but the risk of breast cancer increases with age. Although there are a number of treatments for breast cancer, previous work has suggested that certain factors may affect whether a woman gets treatment. For example, older women are less likely than younger women to be entered into trials of treatment for breast cancer, and therefore treatment guidelines are not as clear for older women. They may also be less likely to receive breast cancer screening.The researchers wanted to look at whether the age of women affected both their survival rate and the treatment they were likely to receive for breast cancer.They studied 9,059 women aged 50–84 years, diagnosed with primary breast cancer between 1992 and 2002 in one health-care region in Sweden. The researchers found that relative survival over five years of women between 70 and 84 years of age was up to 13% lower compared to women aged 50–69 years. The difference in survival was most pronounced in women who had been shown to have more advanced disease or in whom no assessment of the stage of the disease had been made. There were significant differences in disease management found; older women had larger tumors, had fewer lymph nodes examined, and did not receive treatment by radiotherapy or chemotherapy as often as the younger women.In older women, the diagnosis of breast cancer was often made later than in younger women. Once diagnosed, older women were less likely to be fully investigated for their cancer, and had less aggressive treatment. It is possible that other illnesses (co-morbidities) in these women may have meant that they were less likely to survive the cancer, but this cannot be the main cause of the differences, and diagnosis in older women is associated with poorer survival. The large differences in treatment of older women are difficult to explain by co-morbidity alone. Even in a country such as Sweden with good health care, age results in great differences in the diagnosis and care of women with breast cancer, with older women faring much worse than younger women.The US National Cancer Registry has a page with many links to information on breast cancer, including prevention and treatment:http://www.cancer.gov/cancertopics/types/breastCancer Research UK, a large UK charity that funds research into breast cancer, has many pages of patient information:http://www.cancerresearchuk.org/aboutcancer/specificcancers/breastcancerSwedish Cancer Registry:http://www.socialstyrelsen.seRegional Oncologic Centre in Uppsala/Örebro Region:http://www.roc.seSwedish Cancer Society:http://www.cancerfonden.com


Menopausal hormone therapy (HT) is typically withheld from breast cancer survivors because of concerns about risk for recurrence. Our objectives were to estimate the effects of HT on recurrence in breast cancer survivors and to examine the reliability of these estimates.In a systematic review of the literature we identified all reports of HT use in breast cancer survivors that included comparison groups. Study design features that might affect selection of participants, detection of recurrence, and manuscript publication were assessed. The relative risks for breast cancer recurrence associated with HT were combined with random effects models.Two randomized and eight observational studies included 1,316 breast cancer survivors who used HT and 2,839 nonusers. In the observational studies, HT users were younger and more commonly node negative; only two reported balanced restaging for HT and control groups. Randomized trials suggest that HT increased the risk for recurrence , whereas observational studies suggest that HT decreased this risk .Results from observational studies of HT conducted in breast cancer survivors are discrepant with results from randomized trials. Observational studies of HT use in breast cancer survivors have design limitations that cannot be controlled for using standard statistical methods. Therefore, the randomized clinical trial data provide the only reliable estimates of the effect of HT use on recurrence risks in breast cancer survivors. Most breast cancer survivors are menopausal either at diagnosis or as a result of premature therapy-induced menopause, and they frequently experience climacteric symptoms . MenopauThe available data from observational studies indicate that use of HT is associated with increased risk for breast cancer . In postThe objectives of this meta-analysis were to estimate the impact HT has on recurrence risk among observational and randomized studies, and to examine the reliability of these estimates.A previous Medline search from 1966 to 1999  was updaTwo of the authors (NFC and JAK) independently abstracted data on the following variables: sample size, age at diagnosis and at trial induction, tumor stage, nodal status, estrogen and progesterone receptor status, disease-free interval (DFI) between initial breast cancer diagnosis and initiation of HT, type and duration of HT used, follow up after initiation of HT, and number and timing of breast cancer recurrences.Each study was systematically reviewed for features that could introduce bias, including procedures for identifying participants, whether institutional review board approval and/or informed consent was obtained, whether risk factors for recurrence were similar at diagnosis, and whether restaging before entry (to exclude metastatic disease) and duration of follow up were similar for HT users and nonusers. Observational studies were classified as 'clinical experiences' if one or more study authors provided health care to the cohort with potential participation in the decision to use HT.When not reported, the follow up after HT initiation was assumed to equal the duration of HT use. Any second breast cancer event  was treated as a recurrence because studies did not consistently make these distinctions.Relative risk (RR) and 95% confidence interval (CI) were calculated for each study for the recurrence rate and mortality rate among HT users and nonusers. A random effects model was used to estimate the combined RR for randomized and observational studies using Meta-Analyst .Ten studies were identified, including a total of 1,316 breast cancer survivors who used HT and 2,839 who did not. Of these 10 studies, two were unblinded randomized controlled trials without placebo arms , one begBoth randomized trials were conducted in Europe (one in England and one in Sweden). They involved a total of 445 patients with a mean age of 55.5 years, a mean DFI of 33.2 months, a duration of HT use of 19.9 months, and a mean follow-up period after HT initiation of 25.2 months  experienced a recurrence of their breast cancer during follow up. Among the 2,477 nonusers in these studies, 451 (18.2%) had a recurrence. The average annual recurrence rate was 3.3% (range 0.6–7.1%), with substantially higher rates in the randomized trials. Combining all studies yielded a RR for recurrence of 0.84  declare that they have no competing interests.NC conceived the study (with RC), designed the study, reviewed the source studies, abstracted data, drafted the paper, and supervised the statistical analyses. JK participated in the design of the study and reviewed the source studies, abstracted data, carried out the meta-analysis, and helped to draft the manuscript. RC conceived of the study (with NC), designed the analysis, participated in its coordination, and helped to draft the manuscript. All authors read and approved the final manuscript.


A case-control study on cancers of the oral cavity was conducted by utilising data from the population based cancer registry. Bangalore, India. Three hundred and forty-eight cases of cancers of the oral cavity (excluding base tongue) were age and sex matched with controls from the same residential area but with no evidence of cancer. The relative risk due to pan tobacco chewing was elevated in both males and females, being appreciably higher in the latter . A statistically significant (linear test for trend P less than 0.001) dose response based on years, times per day and period of time chewed was seen. Any smoking (cigarette or bidi or both) had only slightly elevated risk of developing oral cancer, whereas a history of alcohol drinking or inhalation of snuff did not influence the risk. A new finding of our study was the markedly elevated risk of oral cancer in persons consuming ragi  in comparison to those not consuming ragi as staple cereal in their diet. There also appeared to be some interaction between ragi consumption and tobacco chewing with substantially higher relative risks in those who pursued both habits compared to those who gave a history of either.


For breast cancer it has been hypothesized that high We used data from the Carolina Breast Cancer Study, a population-based case–control study of incident breast cancer in North Carolina, to examine associations for three possible surrogates of high prenatal estrogen exposure: weight at birth, maternal age, and birth order. We also examined paternal age. Birthweight analyses were conducted for white and African-American women born in North Carolina on or after 1949 . Maternal age was analyzed for US born participants younger than 49 years of age .There was a weak inverse association between birthweight in the highest tertile and breast cancer overall , although associations differed by race . For maternal age there was an approximately threefold increase in risk in women whose mothers were older than 22 years of age, relative to 19–22 years of age, when the women were born. After adjustment for maternal age, older paternal age increased risk in the oldest and youngest age categories . There was no association with older paternal age for white women alone. After adjustment for maternal age , a birth order of fifth or higher relative to first had an inverse association with breast cancer for women younger than 49 years old .Although the CIs are wide, these results lend support to the possibility that the prenatal period is important for subsequent breast cancer risk, but they do not support the estrogen hypothesis as a unifying theory for the influence of this period. Recent epidemiologic studies have investigated the possibility that very early life exposures increase adult cancer risk. Trichopoulos  postulatDespite an overall higher incidence of breast cancer in white women, incidence and mortality rates are higher in young African-American women than in young white women ,4. This The goal of this study was to characterize the relationships of birthweight, maternal age, paternal age, and birth order with breast cancer in African-American and white women in a population-based study. We analyzed data from a subset of women participating in the Carolina Breast Cancer Study (CBCS) , a populn = 861) were women aged 18–74 years, who were mentally competent and resident in the study area at the time of selection with a first diagnosis of histologically confirmed primary invasive breast cancer. They were identified in cooperation with the North Carolina Central Cancer Registry [n = 790) were frequency matched by race and 5-year age group to cases. Trained nurse interviewers collected information and obtained height and weight measurements during interviews conducted at the participant's home. To obtain birthweight and parental ages we requested birth records for all study participants born in the USA on or after 1 January 1948.The CBCS (phase I) is a population-based, case–control study of incident invasive breast cancer conducted between May 1993 and December 1996 in 24 counties of central and eastern North Carolina . ParticiMaternal age was analyzed in the subset of women for whom birth records with maternal age were available Table  and was Birthweight analyses were restricted to women born in North Carolina  and 95% confidence intervals (CIs) were the primary measure of association. PROC GENMOD in SAS  was used with an offset term to account for the age and race specific sampling probabilities used to identify eligible participants . All est2 or >25 kg/m2, calculated from nurse interviewers' measurements of height and weight), first degree family history of breast cancer , and menopausal status were considered potential confounders. Women younger than 50 years were considered postmenopausal if they had undergone natural menopause, bilateral oophorectomy, or irradiation to the ovaries. Multivariable logistic models were used to adjust for potential confounders [Age at menarche (≤12 years or >12 years), age at first full-term pregnancy , lactation , parity , BMI , postmenopausal status , and parity of three or greater .No important differences in breast cancer risk factors emerged between those eligible for the birthweight study and those for whom birthweight was obtained. ORs for age at menarche, age at first pregnancy, and lactation were virtually identical in the full CBCS and all analytic datasets. Differences in ORs between the full CBCS dataset and the birthweight dataset were, as expected, due to age restriction in the latter. In the birthweight dataset, ORs for family history were slightly higher , whereas ORs for the following were slightly lower: BMI greater than 25 kg/mThe distributions of birthweight, parental age, and birth order are presented in Table Tables ORs for maternal and paternal age and breast cancer are presented in Table After adjustment for maternal age, birth order, adult BMI, and household income, there was no association between paternal age and breast cancer among white women. For African-American women, ORs were elevated for both younger (15–22 years of age) and older (35–56 years of age) paternal ages, although CIs were wide. There was no substantial difference in results when the maternal/paternal age datasets were restricted to women born on or after 1 January 1949. Among controls, parental ages were distributed similarly by race, with African-American participants having slightly higher mean maternal and paternal ages than whites.Results for analyses of birth order are shown in Tables We examined the relationships between breast cancer and birthweight, parental age, and birth order among women younger than 49 years of age residing in North Carolina. Overall, there was a weak inverse association with higher birthweight, which was stronger in the full dataset than in the restricted dataset. For white women in the study there was no overall association between birthweight and breast cancer. Among white women born in medical facilities, birthweight in the highest tertile was positively associated with breast cancer, but CIs were wide and included the null. Higher birthweight was inversely associated with breast cancer for African-American women regardless of delivery setting, but again CIs were wide for all estimates. Most previous studies have reported weak to modest positive associations between higher birthweight and breast cancer -22, withIn the USA maternal report and self-report have been the most common sources of birthweight information, rather than birth records. Andersson and coworkers  conducteIn addition to using birth records to decrease misclassification, we performed a separate birthweight analysis for the subset of women who were delivered by physicians in hospitals or doctors' clinics and had their birthweight recorded in pounds and ounces. During the 1950s, home birth and delivery by lay midwives was common practice in North Carolina, particularly among African-Americans and in rural areas, and this could have affected data collection . AdditioAlthough the search strategy employed in this study limited nonlocatable birth records to 3.6% of the study population, and records missing birthweight to 4.0% of locatable records , the missing records were predominantly those of African-American women who self-reported birth in the more rural counties of North Carolina.The inverse associations between higher birthweight and breast cancer seen in this study could also partly be explained by selection bias in the full CBCS dataset if either the case group under-represented the proportion of high birthweight women in the underlying case population or the control group under-represented the proportion of normal weight births in the underlying population. Because birthweights in North Carolina have been increasing over time, more strongly in whites than in African Americans , youngerin utero estrogen exposure increases risk for breast cancer.In the context of a relatively disadvantaged population such as this one, a higher birthweight may be a surrogate for a different constellation of prenatal and postnatal influences than in a relatively advantaged population. Rather than viewing birthweight solely as an indicator of a highly estrogenic prenatal environment, or even specific physiologic processes, birthweight can also be viewed more globally as an indicator of the prepregnancy health of the mother ,32. In tOne limitation of our birthweight analysis is that, lacking an accurate measure of gestational age, it is not possible to interpret fully the association between lower birthweight and breast cancer. Although Andersson and coworkers  reportedOlder maternal age exhibited a moderate positive association with breast cancer in this study. Study participants whose mothers were aged 23 years or older at the participant's birth had approximately twofold to fourfold higher odds of breast cancer than did women whose mothers were between 19 and 22 years of age. Although African-American women whose mothers were aged under 19 years also had elevated odds of breast cancer, the pattern did not differ appreciably between white and African-American women. Although the magnitude of OR for women whose mothers were aged 23–27 years was greater than in previous studies, the findings were consistent with the majority of previous reports: weak positive associations with older maternal age -26,34-42The pattern of association between having an older father  and breast cancer was somewhat different for white and African-American women. After adjustment for maternal age and birth order, paternal age was not associated with breast cancer for white women. This is consistent with previous reports for white women showing little to no effect of paternal age ,38,41,42Birth records with parental age could only be obtained for 76% of CBCS participants born in or after 1948, and were missing almost exclusively by participants' state of birth. Breast cancer mortality is generally higher in the midwest and northeast regions of the USA than in the southeast [In women younger than 50 years of age, higher birth order exhibited a weak inverse association with breast cancer only after adjustment for maternal age. No association was seen in the full CBCS, which included women aged up to 74 years, although data were not available to adjust for maternal age. This is consistent with the majority of previous studies, which have shown either a weak inverse association with breast cancer ,26,36,49Younger African-American women are at higher risk for breast cancer than younger white women ,4. BirthTaken as a whole, the results for birthweight, parental age, and birth order from the present study do not support the estrogen exposure hypothesis as a unifying theory for prenatal influence on adult breast cancer. This emphasizes the importance of further investigating the influence of prenatal factors on breast cancer risk, particularly in multiple populations. Additional hypotheses must be pursued, including the association between birthweight and other hormonal exposures such as insulin-like growth factor I, and between maternal age and endogenous and exogenous mutagenic exposures. Methodologic difficulties involved in investigating prenatal exposures in nonwhite and/or disadvantaged populations are not trivial; nonetheless, this type of investigation must be done to fully understand life course processes that can culminate in breast cancer among women of any background.MEH, BN and RCM participated in the interpretation of results and writing of the manuscript. MEH performed data collection, data entry, and statistical analyses.The authors declare that they have no competing interests.BMI = body mass index; CBCS = Carolina Breast Cancer Study; CI = confidence interval; OR = odds ratio.


COMT, CYP1A1, CYP1B1) and the two estrogen receptors  in the progression of benign breast disease (BBD) to breast cancer.A cohort study was conducted to examine the role of genetic polymorphisms in three estrogen metabolizing enzymes  0.38; 95% Confidence Interval (CI) 0.15, 0.96). Compared to the reference wild-type genotypes, marginally significant associations with the development of breast cancer were observed between carriers of the variant ESR1 – 104062T allele , the variant ESR2 *38A allele , and the variant CYP1B1 453Ser allele .Among all participants, the CYP1B1, ESR1, and ESR2 genes may play a role in progression of BBD to breast cancer among Caucasian women. Although additional studies are needed to confirm or refute our findings, these results suggest that genetic markers may aid in the identification of women who are at risk for progression of BBD to cancer.The results indicate that specific polymorphisms in the  A woman's level of endogenous estrogen may be important in the progression of BBD to invasive breast cancer. Abundant evidence suggests that estrogen is an important factor in the development of breast cancer among average-risk women. This evidence includes findings from recent prospective studies that showed significantly increased levels of serum estrogen in women who developed breast cancer compared to women who did not develop breast cancer [Biopsy-proven benign breast disease (BBD) is a well-defined risk factor for developing invasive breast cancer ,2. Howevt cancer -7. In adt cancer ).CYP1A1, and 4-hydroxylation, which is dominated by CYP1B1 [COMT) [CYP1A1, CYP1B1, and COMT, a number of polymorphisms have been identified, some which have been shown in laboratory studies to be functional (8). The associations of some of these polymorphisms with the risk of developing breast cancer among average risk women have been studied, and most of the findings have been inconsistent  enzymes ; the majy CYP1B1 . The hyd1 [COMT) -13. Withnctional . The assESR1 and ER-β or ESR2 [ESR1 and ESR2 genes and the risk of breast cancer among average-risk women and have reported mixed results [ESR1 and ESR2 with breast cancer risk among women with BBD.While the estrogen metabolizing enzymes may influence the levels of circulating endogenous estrogens and, therefore, contribute to breast cancer risk, the estrogen receptors determine, in part, the action of estrogens on the mammary gland. Estrogen acts on target tissues by binding to the estrogen receptors, which exist in two forms, ER-α or  or ESR2 ,15. Like or ESR2 , and it  results -29. To oCOMT, CYP1A1, CYP1B1) and the two estrogen receptors  and the risk of developing breast cancer among women with BBD. To address this aim, data from a cohort of women with BBD from Washington County, Maryland enrolled in the CLUE-II study were analyzed.The aim of the present study was to analyze the associations between genetic polymorphisms in three estrogen metabolizing enzymes (Campaign against Cancer and Heart Disease") was conducted in Washington County, Maryland to establish a cohort with associated blood samples [In 1989, a campaign named CLUE II , about 30 percent of the Washington County residents, participated in the study. In addition to the information collected from this cohort at baseline in 1989, follow-up data were obtained from questionnaires administered in 1996 and approximately every 2 years thereafter. The Institutional Review Board at the Johns Hopkins Bloomberg School of Public Health approved this study.The BBD cohort is a sub-set of CLUE II. Details of the selection of CLUE II participants included in the BBD cohort are described elsewhere . BrieflyFor this analysis, 17 of the 1467 women were excluded because DNA could not be obtained from their stored blood samples and polymorphisms could not be genotyped. Further, all non-Caucasians (n = 12) were excluded from the analysis because previous studies have shown that race is an important confounder or effect modifier in investigations of polymorphisms and disease. These exclusions accounted from less than 1% of the BBD cohort. After applying these exclusions, the final analytic cohort included 1438 Caucasian women who were successfully genotyped for at least one of the genetic polymorphisms investigated in this study.in situ or invasive breast cancer  were identified through linkage of the cohort participants with the Washington County Cancer Registry and, since 1992, with the Maryland State Cancer Registry. The Washington County Cancer Registry identifies cancer cases from discharge records and pathology reports from Washington County Hospital, which is the only hospital in the county, and from death certificates. Since 1992, all hospitals cancer diagnostic laboratories, and radiation therapy centers in Maryland have been required to report incident cancer cases to the Maryland Cancer Registry, and currently, the Maryland Cancer Registry is certified as being more than 95% complete by the North American Association of Central Cancer Registries. While it is possible that cases of in situ or invasive breast cancer may have been missed due to migration out of the state after 1996, all women in the BBD cohort had at least 7 years of follow-up data (1989 to 1996). Further, approximately 80% of the BBD cohort responded to the 2000 follow-up questionnaire, indicating that the vast majority of the cohort remained under active surveillance in 2000.Incident cases of in situ and 76 cases of invasive breast cancer were identified after the diagnosis of BBD.Active case surveillance for the BBD cohort ended on April 28, 2003. In total, among all of the women included in the BBD cohort, 15 incident cases of COMT, CYP1B1, CYP1A1, ESR1 and ESR2 was conducted at Applied Biosystems (ABI) and Celera Laboratories. All polymorphisms were genotyped using TaqMan technology . The genotyping success rates of the polymorphisms selected ranged from 91.8% to 97.6%, with the exception of the CYP1B1 Arg48Gly polymorphism for which the genotyping success rate was 84.2%. The 84.2% genotyping success rate for CYP1B1 Arg48Gly polymorphism was due to a problem with the laboratory assay that was not resolved during the study period.Single nucleotide polymorphisms (SNPs) analyzed in the present study were selected as part of a larger study investigating the broad impact of genetic variation in candidate genes and their interactions with environmental exposures on cancer incidence and survival. For the larger study, polymorphisms that were suggested to alter function, encoded for a nonsynonymous amino acid change, or were located within the 5' or 3' untranslated region (UTR) of the gene and thus could potentially alter mRNA stability were chosen. Descriptions and dbSNP identifiers of the polymorphisms selected are shown on Table in situ or invasive breast cancer. Unconditional logistic regression was used to estimate age-adjusted odds ratios (ORs) and 95% confidence intervals (95% CIs) for the associations between the polymorphisms the development of breast cancer. Because previous studies indicate that the associations between several of the analyzed polymorphisms and the development of cancer may differ according to body mass index, smoking status, and alcohol intake, we conducted exploratory analyses to examine the associations between all of the polymorphisms and the development of breast cancer among strata of these variables . Further, these analyses were conducted for all participants and for pre- and post-menopausal participants separately. Because the number of events among the pre-menopausal women was low (n = 24) and ORs for some of the genotypes could not be calculated, only the analyses for all participants and the post-menopausal subgroup are reported. As an additional exploratory analysis, logic regression [The outcome variable examined in these analyses was the development of gression  was emplTo address the issue of multiple testing in this study, p-values for the associations between single nucleotide polymorphisms and breast cancer risk were adjusted for the false discovery rate using the method proposed by Benjamini and Hochberg  in the sUnless otherwise specified, analyses were performed using SAS Version 8.2 . A p-value of less than 0.05 was considered to be statistically significant.in situ breast cancer after an initial breast biopsy for BBD.Characteristics of the analytic cohort are reported in Table CYP1B1 Ile462Val polymorphism . Although statistically significant, the observed genotype counts for the CYP1B1 Ile462Val polymorphism were similar to the expected genotype counts under Hardy-Weinberg equilibrium . All ESR2 polymorphisms were in strong linkage disequilibrium (D' > 90). Among the ESR1 polymorphisms, the Ser10Ser and Ala87Ala polymorphisms were strongly linked (D' > 90).All of the polymorphisms examined were in Hardy-Weinberg equilibrium among women not developing breast cancer, with the exception of the CYP1B1 453Ser allele had a borderline statistically significant increase in the risk of developing breast cancer compared to women carrying the referent Asn/Asn genotype . The other polymorphisms in the estrogen metabolizing enzymes were not associated with breast cancer risk among women with BBD in this study. Results were not substantially altered by BMI, alcohol intake or smoking status (results not shown). No significant interactions between the genotypes were observed. To note, after adjustment for multiple testing, none of the associations between polymorphisms in the estrogen metabolizing enzymes and the risk of developing invasive breast cancer were statistically significant.The associations between polymorphisms in the estrogen metabolizing enzymes and the risk of developing invasive breast cancer among women with BBD are shown in Table ESR1 and ESR2 and the risk of developing invasive breast cancer among women with BBD are shown in Tables ESR1 – 104062T allele compared to carriers of the referent genotype . Among all participants, the ESR2 *5772G allele was associated with a statistically significant decrease in the risk of breast cancer among women with BBD . A marginally significant increase in the risk of developing cancer was observed among women carrying at least one ESR2 *38A allele compared to the women homozygous for the GG genotype . OR estimates of the ESR2 *5772G and the ESR2 *38A polymorphisms were attenuated after adjustment for the presence of the other polymorphism . Other ESR1 and ESR2 polymorphisms examined were not associated with breast cancer risk among women with BBD. Results did not differ substantially by BMI, alcohol intake or smoking status (results not shown). No significant interactions between the ESR1 and ESR2 genotypes were observed. After adjustment for multiple testing, the associations between the ESR1 and ESR2 polymorphisms and breast cancer described above were not statistically significant.The associations between polymorphisms in CYP1B1 453Ser allele compared to women who carried two copies of the CYP1B1 453Asn allele. None of the previously published studies on the CYP1B1 Asn453Ser polymorphism and breast cancer conducted among average-risk women reported an increase in risk of breast cancer associated with this polymorphism [Asn/Ser genotype and an OR of 0.85  associated with the homozygous Ser/Ser genotype [CYP1B1 polymorphic variant is associated with both higher catalytic activity in converting estrogen to 4-hydroxy estrogens and greater levels of DNA damage [In this population-based cohort of women with BBD, there was evidence of an increased risk of breast cancer among women who carried the morphism -38, inclgenotype . HoweverA damage -41. ThisESR2 *38G>A. This finding is not consistent with results of published studies among either average-risk or high-risk women. Maguire et al [*38A allele among average-risk  or high risk . In addition, Gold et al [ESR2 *38G allele were associated with an increased risk of breast cancer among Ashkenazi Jews. These differences in findings may be due to the different populations under study; Maguire et al [ESR2 polymorphisms among patients in Sweden and Gold et al (16) investigated ESR2 and breast cancer among the Ashkenazi Jews. Neither investigated the association of ESR2 polymorphisms among women diagnosed with BBD.A marginally significant positive association was observed for the re et al  reportedld et al  observedre et al  examinedESR2 *5772A>G polymorphism or the ESR1 – 104062C>T polymorphism are at decreased risk of developing breast cancer. To our knowledge, neither of these genotypes has been examined in women with BBD or among average risk women. The regions surrounding each polymorphism are well conserved with little recombination, therefore, it likely that, if the associations are real, the observed associations are due to linkage disequilibrium with another functional polymorphism in the region. No information on functionality is know for either ESR2 *5772A>G or ESR1 – 104062C>T.In addition, results from this study suggest that women with BBD who carry the COMT and CYP1A1, and breast cancer risk. Although no published study has investigated the COMT Val158Met and CYP1A1 Ile462Val polymorphisms in the progression of BBD to invasive breast cancer, previous studies of average-risk women have reported discrepant results regarding the association between the COMT Val158Met and the CYP1A1 Ile462Val polymorphisms and the risk of breast cancer [COMT 158Met allele is associated with three- to four-fold decreased activity compared to the wildtype allele [CYP1A1 462Val allele is consistent with higher enzyme activity [There was no evidence of an association between the other polymorphisms examined in this study, including those in t cancer . Both poe allele  and the activity . TherefoWhile this study provides novel information regarding the role of polymorphisms in estrogen metabolizing enzymes and the estrogen receptor genes in the progression of BBD to breast cancer, this study has several limitations inherent to its design. As reported in a previously published investigation on this cohort of women , patholoCOMT, CYP1B1, CYP1A1, ESR1 and ESR2 and the risk of breast cancer in Caucasian women with BBD. We had limited power to detect small associations and, therefore, were also limited in our ability to correct for multiple testing. As stated in the results section, the associations between the polymorphisms and the risk of developing breast cancer were not statistically significant after correction for multiple testing and this may have been due, in part, to the small sample size. However, while we may be able to rule out large changes in risk of clinical and public health consequence associated with certain genotypes, we still observed, with the small number of events, statistically significant changes in the risk of breast cancer in this cohort. Taken together with functional considerations of these polymorphisms, it is important to follow-up on these observations to determine if we can better understand and perhaps intervene for those women with BBD who are most at risk to progress to cancer.In addition, though the base cohort is relatively large, the number of cases of breast cancer occurring limited the power of the study to make firm conclusions about the relationships between polymorphisms in CYP1B1, ESR1, and ESR2 genes may play a role in progression of BBD to breast cancer among Caucasian women. Although additional studies are needed to confirm or refute our findings, these results suggest that genetic markers may aid in the identification of women who are at risk for progression of BBD to cancer.The findings of this study indicate that specific polymorphisms in the BBD Benign breast diseaseCOMT Catechol O-methyltransferaseCYPs Cytochrome P450 enzymesESR1 Estrogen receptor-alphaESR2 Estrogen receptor-betaSNP Single nucleotide polymorphismThe author(s) declare that they have no competing interests.LG contributed to the statistical analysis, interpretation of the data, and the writing of the manuscript. SIB provided expertise on the more advanced analyses of the genetic data and contributed to the interpretation of the data. MAM, LWT, and SAH contributed to the data collection and statistical analysis. PA conducted reviews of the pathology report data and pathology specimens. CJN and KJN contributed to the conception and design of the study and the interpretation of the data.The pre-publication history for this paper can be accessed here:


The general lack of clear associations between diet and breast cancer in epidemiological studies may partly be explained by the fact that breast cancer is a heterogeneous disease that may have disparate genetic associations and different aetiological bases.A total of 346 incident breast cancers in a prospective cohort of 17,035 women enrolled in the Malmö Diet and Cancer study (Sweden) were subcategorized according to conventional pathology parameters, proliferation and expression of key cell cycle regulators. Subcategories were compared with prediagnostic diet and body measurements using analysis of variance.P = 0.03 and 0.009, respectively), whereas low energy and unadjusted fat intakes were associated with high proliferation . Low intakes of saturated, monounsaturated and polyunsaturated fatty acids were also associated with high proliferation . Low energy and unadjusted fat intakes were associated with cyclin D1 overexpression , whereas cyclin E overexpression was positively correlated with fat intake. Oestrogen receptor status and expression of the tumour suppressor gene p27 were not associated with either diet or body constitution.A large hip circumference and high body mass index were associated with high grade tumours  intakes, and high body mass index were associated with relatively more malignant breast tumours. Dietary behaviours and body constitution may be associated with specific types of breast cancer defined by conventional pathology parameters and cyclin D The aetiology of breast cancer is complex, but a number of risk factors have been identified. In human studies body mass index (BMI) and hip and waist circumferences have been described as positively associated with risk for developing breast cancer . Animal The association between dietary intake and body composition is still under debate ,4, and t1 or cyclin E affect the cell cycle at the G1/S checkpoint and may affect chromosomal stability ). Similar results were obtained for energy intake and time to diagnosis .A prevalent or subclinical breast cancer may affect anthropometric measurements and dietary habits. All data concerning objective body measurements were gathered between 0.2 and 10.4 (mean 4.3) years before breast cancer diagnosis, and the values were therefore most likely unaffected by disease. Supporting this interpretation is the lack of relation between BMI and time to diagnosis (Tumour classification with regard to type and grade was performed according to current classification systems. The tissue microarray (TMA) technique used in this study is now a well documented method for high-throughput tissue screening, with two tissue cores considered a sufficient sampling amount ,29. The The participation rate in the MDCS was about 40% of the potential participant population. The participants did have a higher incidence of breast cancer compared with the source population  and wereBecause several methodological factors in the MDCS may affect dietary measurements, all analyses were adjusted for diet assistant, period of data collection, diet methodology and past food habit change, as well as for total energy intake when stated. Hence, these factors ought not to have confounded dietary assessments. It was decided not to adjust the present analysis for established risk factors for breast cancer or factors that affect true dietary intake (for example socioeconomic index), because the main objective was to conduct perform a descriptive and exploratory analysis of dietary intake in different groups of breast cancer as defined by pathological and biological properties.P values should be interpreted with caution. Because no previous study has addressed the same issue using our methodology, we consider the present analyses as a first, hypothesis-generating study. Our findings need confirmation in future studies including healthy control individuals.The present study includes a large number of comparisons, and In this report we demonstrate an association between highly proliferative tumours and low energy intake, as well as low intakes of fat and PUFA. Several other human studies have reported that high energy intake is related to increased risk for breast cancer ,32, but 1. Cyclin E, however, was positively associated with fat intake, but this association did not remain significant in the dichotomized analyses. The opposite behaviours for cyclin D1 and cyclin E are in accordance with earlier observations showing that cyclin E overexpressing tumours are low in cyclin D1 and vice versa [1 cell cycle arrest, possibly through increased expression of p27 and reduced expression of cyclin D1 [1 overexpression, and p27 did not exhibit any connection to energy intake. However, animal models using chemically induced breast tumours cannot readily be translated into a far more complex tumour genesis in humans, which presumably are influenced by a multitude of environmental factors.Furthermore, we found an association between low energy intake, particularly low fat intake, and overexpression of cyclin Dce versa . Experimyclin D1 ,34. ThisSubgroups defined by ER were not linked to dietary behaviour or body composition. Some studies indicate that high fat diets are associated with increased risk for ER-positive tumours -37, wherIn contrast to fat, protein and carbohydrate were not significantly associated with any specific tumour characteristics. A recently published report  indicateThe tumour-promoting effects of fat may be dependent on amount as well as type . In the Body composition, expressed in terms of BMI, waist and hip circumference, and height, was associated with tumour grade, and slender body constitution corresponded with low-grade tumours. The association between body constitution and breast cancer stage has been reported in other studies ,47, and In the present study body size and distribution of body fat were clearly associated with histological grade, whereas energy intake – with an emphasis on fat – appeared to influence the proliferation rate and overexpression of cell cycle regulators. The image of a slender figure with high energy and fat intake and a correspondence with a less malignant phenotype may seem controversial. However, similar to other epidemiological studies ,48, enerAlcohol intake was not associated with any of the breast cancer subgroups examined, but a previous report from the MDCS identified an association between high intake of wine or total alcohol (nonsignificant) and increased breast cancer risk .1 and E might be a useful approach when studying breast cancer in relation to dietary behaviours and body constitution. Further studies are needed to improve the delineation of women at risk for developing highly malignant breast cancer and, hopefully, to contribute to novel prevention strategies.The above findings indicate that the strategy of subgrouping breast cancer according to proliferation, tumour grade and expression of cyclin DBMI = body mass index; ER = oestrogen receptor; MDCS = Malmö Diet and Cancer Study; MUFA = monounsaturated fatty acids; PUFA = polyunsaturated fatty acids; SFA = saturated fatty acids; TMA = tissue microarray.The authors declare that they have no competing interests.SB carried out the immunohistochemical assessment, performed the statistical analysis and drafted the manuscript. EW participated in the design of the study and interpretation of data, and helped to draft and revise the manuscript. KJ supervised the immunoassays and helped to draft the manuscript. LA re-evaluated tumours according to type and grade, and participated in the design of the study. BG conducted the statistical design and provided statistical support. GB participated in the design of the study. JM revised the manuscript critically. GL participated in the design of the study and interpretation of data, and helped to draft the manuscript. All authors read and approved the final manuscript.


PGR), can potentially contribute to an individual's susceptibility to breast cancer. It has been reported that the PROGINS allele, which is in complete linkage disequilibrium with a missense substitution in exon 4 , is associated with a decreased risk for breast cancer.Recent evidence suggests a role for progesterone in breast cancer development and tumorigenesis. Progesterone exerts its effect on target cells by interacting with its receptor; thus, genetic variations, which might cause alterations in the biological function in the progesterone receptor  polymorphism . In addition, we did not observe an interaction between this allele and menopausal status and family history of breast cancer as reported previously.Overall, our study does not support an association between the Val660→Leu PROGINS polymorphism and breast cancer risk. PGR, which exists as a single-copy gene. The PGR gene uses separate promoters and translational start sites to produce two protein isoforms, hPR-A and hPR-B [PGR gene might predispose women to breast cancer. Several studies have investigated the Val660 →Leu G/T polymorphism and the PROGINS Alu insertion, which are in complete linkage disequilibrium [Until recently, the role of progesterone on mammary gland tumorigenesis was not well understood. Data from epidemiological studies revealed a higher risk for breast cancer in postmenopausal women who used a combination of estrogens and progestins, in comparison with those women who used estrogens alone ,2. As dend hPR-B -5, that nd hPR-B ,7. Althond hPR-B  that mednd hPR-B ,10. The nd hPR-B ,12. Selend hPR-B . Given tilibrium , in assoilibrium -17. In t®) by the ABI PRISM 7900HT Sequence Detection System . TaqMan primers, probes, and conditions for genotyping assays are available from the authors on request. Genotyping was performed by laboratory personnel blinded to case-control status, and blinded quality control samples were inserted to validate genotyping procedures. Concordance for the blinded samples was 100%.Detailed information about this nested case-control study and exposure data has been reported previously . The pro2) at age 18 years, weight gain since age 18 years, age at menarche, parity/age at first birth, duration of postmenopausal hormone use, first-degree family history of breast cancer, and history of benign breast disease. We also adjusted for age at menopause in analyses limited to postmenopausal women. Indicator variables for all genotypes were created by using the wild-type genotype as the reference category in the regression models. Because of the low prevalence of homozygous variants, we combined heterozygotes and homozygotes in the logistic regression analysis. Interactions between genotypes and breast cancer risk factors were evaluated by including appropriate interaction terms in unconditional logistic regression models. The nominal likelihood ratio test was used to assess the statistical significance of these interactions. We used SAS version 8.0  for all analyses. We tested Hardy–Weinberg agreement by using a χ2 test.Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated by using conditional and unconditional logistic regression. In addition to the matching variables, we adjusted for breast cancer risk factors: body mass index (BMI) (kg/m2) and weight gain since age 18 years (11.6 versus 11.3 kg). In comparison with controls, cases had similar ages at menarche (12.5 versus 12.6 years), first birth (23.0 versus 23.0 years) and age at menopause (48.2 versus 47.9 years). The proportion of women with a first-degree family history of breast cancer was significantly higher among the cases (20.0% versus 15.0%). Cases were also more likely to have a history of benign breast disease (64.0% versus 51.0%) and a longer duration of postmenopausal hormone use (50.3% versus 49.7% current users for five or more years). The study population was predominantly Caucasian .Our study included a total of 1323 incident breast cancer cases, diagnosed after blood draw to 1 June 2000, and 1854 matched controls. Of these, 1134 cases and 1640 controls were postmenopausal at blood draw, and 112 cases and 121 controls were premenopausal; menopausal status was uncertain in 77 cases and 93 controls. The mean age of cases at blood draw was 57.3 years; for controls it was 57.9 years. Cases and controls had similar mean BMI at blood draw  were evaluated [Our data do not support an inverse association between the Val660→Leu polymorphism and breast cancer risk as reported previously . These rvaluated . We had None declared.BMI = body mass index; CI = confidence interval; LD = linkage disequilibrium; OR = odds ratio PGR = progesterone receptor.


Previous epidemiological studies have inconsistently shown a modestly increased breast cancer risk associated with hormone replacement therapy (HRT). Limited information is available about different formulations – particularly concerning different progestins.A case-control study was performed within Germany in collaboration with regional cancer registries and tumor centers. Up to 5 controls were matched breast cancer cases. Conditional logistic regression analysis was applied to estimate crude and adjusted odds ratios (OR) and 95% confidence intervals (95% CI). Stratified analyses were performed to compare the risk of different estrogens, progestins, and combinations.A total of 3593 cases of breast cancer were identified and compared with 9098 controls. The adjusted overall risk estimate for breast cancer (BC) associated with current or past use of HRT was 1.2 (1.1–1.3), and almost identical for lag times from 6 months to 6 years prior to diagnosis. No significant trend of increasing BC risk was found with increasing duration of HRT use, or time since first or last use in aggregate. Many established BC risk factors significantly modified the effect of HRT on BC risk, particularly first-degree family history of BC, higher age, lower education, higher body mass index (BMI), and never having used oral contraceptives (OCs) during lifetime.Whereas the overall risk estimates were stable, the numbers in many of the sub-analyses of HRT formulation groups  were too small for strong conclusions. Nevertheless, the BC risk seems not to vary much across HRT formulation subgroups. In particular, no substantial difference in BC risk was observed between HRT containing conjugated equine estrogens (CEE) or medroxyprogesterone acetate (MPA) and other formulations more common in Europe.The BC risk of HRT use is rather small. Low risk estimates for BC and a high potential for residual confounding and bias in this observational study do not permit causal conclusions. Apparently, there is not much variation of the BC risk across HRT formulations . However, the small numbers and the overlapping nature of some of the subgroups suggest cautious interpretation. Discussion surrounding the role of steroid hormone formulations in carcinogenesis is complex, i.e. providing arguments for both benefits and risks in short and long-term use  In 1968 In addition to their efficacy for the treatment of vasomotor symptoms benefits of HRT have been shown by observational studies and clinical trials for the prevention of osteoporosis and fractures ,6, as weThe overall risk of breast cancer associated with HRT has shown variation, but has mainly been reported as significantly increased but well under a risk estimate of 2.0 ,13. In pThe objective of this publication is to present data on BC risk associated with HRT use in Germany were CEE/MPA is less frequently used than formulations based on estradiol and a large series of progestin other than MPA. This paper is also focused on the question of different BC risk in different HRT formulation sub-groups.The objective of this case-control study was to provide evidence regarding the presence or absence of differential effects of HRT formulations used in Europe on cancer risks or benefits in collaboration with German cancer registries and tumor centers. The study was planned in early 2003 (performed 2004–2005), and was justified by the working hypothesis that the results obtained with the HRT formulation CEE/MPA might be not generalizable for Europe with HRTs of other estrogens and progestins. This study on HRT was made possible by earlier collaborative research with German cancer registries and tumor centers in the field of gynecological cancer and exogenous steroid hormone use -16. The Cancer registries in Schleswig Holstein, Hamburg, and the common registry for the "five new states" (former East Germany) participated in this study, as well as clinical tumor centers throughout Germany.The exposure data (sex steroid hormone use) were recorded by month and year of exposure  as well as the date of diagnosis of cancer. The information was compiled primarily based on a questionnaire. The cancer registries distributed the questionnaires to the breast cancer cases. The participation was voluntary and a consent form was required.The study protocol and questionnaire were approved by the relevant Ethical Committee and the Office of Data Privacy.The Centre for Epidemiology & Health Research Berlin (ZEG Berlin) coordinated the study. A number of university-based and other collaborators contributed with ideas/proposals to the study, specific sub-studies, evaluation, and interpretation.Eligible cases were those of histologically confirmed breast cancer (ICD 10: C50) diagnosed until 2004 inclusively in women of all age groups. The vast majority got their breast cancer diagnosed between 2000 and 2004, but 7% before 2000. Subjects had to be alive and in sufficiently good shape to complete the questionnaire in order to qualify as cases for the study. Cases were considered non-eligible if they showed a history of other malignant tumors or missing time variables .An initial total of 3717 BC cases were identified. Of these, 124 cases were excluded for different reasons: in 66 cases the diagnosis was not fully confirmed, and 58 had a uterine or ovarian cancer before or in the same time window as BC. Thus 3593 BC cases were used for this analysis.The participants of the German Cohort Study on Women's Health, that were shown to be representative for German Women in many aspects -17, wereTime-related information on lifetime history of hormone use as well as data on reproductive life, lifestyle pattern, conditions/diseases, and some other factors were obtained via a self-administered postal baseline questionnaire. Other studies have shown that the recall of hormone use history (type and duration of use) can be reliably obtained from women even for periods far in the past -20. The not mutually exclusive but rather overlapping, i.e. women might have used more than one of the HRT formulations during lifetime and therefore counted more than once. In many of these subgroups, we expected to run out of numbers because of low exposure prevalence.The type of HRT formulation was classified into five broad categories: estrogen/progestin alone, combination type, estrogen type, progestin type, and CEE/MPA category. The lifetime history of HRT use was divided into multiple sub-groups: "only HRTs" (estrogen only and progestagen only), combination form , according to the estrogen type , according to progestins , and mutually exclusive categories of CEE/MPA combinations . Each participant who had ever used HRT was classified in accordance with these categories, which are We considered an important possible bias for analysis using the logistic regression model: The possibility cannot be excluded that prior to the final diagnosis of breast cancer, the women and/or their physicians might have been aware of "warning signs"  that may have led to a decision not to use HRT. In addition, knowledge about HRT might have led to more intense screening/diagnostics for early forms of cancer. We therefore introduced several index dates (= different lag times): For example, we disregarded HRT use and other exposure information in the last six months prior to the final cancer diagnosis across all analyses, i.e. for both cases and controls. A series of further index dates was introduced, such as 2, 4, and 6 years, i.e. all exposure-related information prior to these dates was ignored in the respective analyses. It may be debated whether 6 years prior to diagnosis is too long a period to disregard information, because HRT use during the 6 years before diagnosis might well have promoted tumor growth leading to earlier diagnosis. Attempts to establish whether this is a problem were undertaken by analyzing the effect of increasing length of time since first and last HRT use as well as duration of use.The main analysis was done with conditional logistic regression. Crude and adjusted odds ratios (OR) were reported with 95% confidence intervals (95% CI). Adjustment was done for BMI, family history of breast/uterine/ovarian cancer, child-bearing history, age at first live birth, duration of breast-feeding, age at menarche, OC use, and education. If values were missing for the adjustment variables, we used automatically imputed figures such as modal values. For sub-group analyses where the matching effect got lost due to other group definitions (HRT formulation subgroups), we adjusted for age and residency to replace the matching. We were not able to use age at menopause as co-variable because it could not be reliably determined for a high proportion of participants.The number of cancer cases was – despite the large total number – too small for many sub-analyses (e.g. HRT formulation subgroups), we refrained from complex adjustment to prevent unstable risk estimates, and i.e. we adjusted only for age and residency. Moreover, we did not calculate risk estimates if any cell of the "two-by-two" table contained less than 5 women.We analyzed the impact of duration of HRT use compared to never-use . The time elapsed from first HRT use to the manifestation of BC was categorized as follows: never-use, 1–4 years, 5–9 years, 10–14 years, 15+ years. The respective categories for time since last use were: never-use, <1 year, 1–2 years, 3–4 years, and 5+ years ago. Short use (less than 1 year) might be differently recalled by women with cancer cases versus those without cancer (if longer ago).It was not possible to define mutually exclusive exposure categories to analyze individual HRT formulations. Use of HRT formulations partly overlaps across life histories due to switching pattern. Furthermore, it was not feasible to define sufficiently large groups with exclusive use of only one specific hormonal formulation group. Therefore, comparison of risk estimates across exposure groups provides only an impression as to whether there are substantial differences in cancer risk.We abstained also from defining categories of HRTs or compounds "longest used during lifetime", because of the arbitrary character of the decision as well as the assumed incompatibility for what "longest" might mean across different compounds.The statistical packages SAS 9.1 and STATA 8.0 were used.Table Other descriptive data in Table We analyzed the cancer risk of HRT ever use vs. never use Table  with conTable Duration of HRT use was apparently very little associated with breast cancer risk in our study. Two slightly increased risk estimates were observed : duration up to 2 years and 8+ years. No significant trend of increasing breast cancer risk with increasing duration of HRT use was found.Up to 10 years since first use the risk marginally increased in the two lower categories (up to 10 years until diagnosis). The risk estimates varied between 1.0 and 1.2 – and without trend of increasing risk with increasing time of diagnosis since first use.Similarly, no trend of increasing cancer risk with increasing time since last HRT use was seen. The risk estimates were not significant and close to 1.0, with the exception of a non-significant cancer risk estimate for 5 years and more since last HRT use .Established risk markers for breast cancer such as age at diagnosis , number of live births, breast feeding, OC use, BMI, family history of BC, or education were analyzed for modifying the association of HRT use and BC. All variables in Table To our surprise, there seemed to be a lower impact of HRT use on BC risk with increasing duration of past use of OCs, which needs further attention in future studies. The adjusted BC risk estimates were according to duration of OC use: never use [1.38 (1.04–1.84)], up to 2 years OC use [0.96 (0.39–2.34)], 2–4 years [not sufficient numbers for conditional analysis], 5–10 years [0.89 (0.32–2.41)], and for 10 and more years [0.72 (0.50–1.05)].The aim of the analysis of different HRT formulation groups was to provide a crude, visual comparison of different groups of different HRT formulation across groups. The name of each formulation category in table The number of exposed cases and controls were very different across the subgroups of ever use of estrogens and progestins during lifetime. If numbers of exposed cases or controls were less than 5 (in any cell of the two-by-two table for risk estimation), the ORs were not calculated (labeled as n.d. = no data). Moreover, the loss of data during adjustment may leads in some instances also to the label "n.d.". Table We distinguished between different routes of administration , between therapy with exclusive use of estrogens or progestins throughout the entire lifetime (i.e. no other HRT was ever used), we considered two different estrogen/progestin combinations , focused on the use of CEE and MPA specifically, and examined different estrogens and progestins.The oral route of administration dominated in the participants of our study. HRT use of the oral route showed a mainly non-significant association with BC risk, which shows an increasing trend of risk with longer duration of use, i.e. becoming significant after 10 and more years of use. Transdermal use, however, did not show an increased risk of BC as did other forms of administration.The BC risk associated with different formulation categories is small, and often not significantly different from never-use (as referent category = 1.0). Risk estimates for some formulation categories seem to be lower than unity , others showed slightly, but significantly increased risk (e.g. continuous combined regimens) – if numbers are taken at face value.Mono-therapies with estrogens or progestins seem to be different. Whereas exclusive estrogen use seems not to be associated with an increased risk of BC (even a non-significant tendency toward lower risk) than never use and depict no trend with increasing duration, "progestin-only" is also not significantly associated with BC risk but seems to show a trend of increasing risk with increasing duration of use.Taken at face value, continuous combined regimens were associated with higher risk estimates (mostly significant) than sequential regimens (mainly non-significant). All E+P formulations together were associated with marginally higher BC risk estimates than estrogen- or progestagen-only formulations.As far as CEE and MPA are concerned – no noteworthy increases in risk were evident if used combined or separately. Taking risk estimates at face value, there is no difference in risk when compared to all other formulations not containing CEE or MPA .Of the progestins, only NETA showed a slightly increased BC risk estimates. NETA showed – unlike all other progestins – an apparent upward trend with increasing duration of use. Small numbers and large confidence intervals should be considered.Cancer of the breast is the most commonly occurring cancer in women, and the third most common cancer overall. Incidence and mortality for this and other gynecological cancers are still increasing in many parts of the world, especially in developed societies.An expert panel from the American Institute of Cancer Research published an extensive review on "Food, Nutrition and the Prevention of Cancer", with consideration of all potential risk factors, beside others, also external use of hormones . The panAnalysis of the effect of external hormones on gynecological cancer must take into account the lag time of cancer development. Lag time is likely to be long and may vary depending on complex unknown causal mechanisms, and is therefore an issue involving complex, time-dependent risk factors. It is difficult for observational studies to account sufficiently for time-dependent variables. Age, time, and duration of use are only indicator variables. Moreover, observational studies in general are prone to bias and residual confounding, even if their performance is "state-of-art". This is a methodological problem in particular, because observed risk estimates were usually small (less than or around 2.0 or 0.8 at the other side of the risk continuum), especially those associated with use of HRT/hormones. Given the great potential for residual confounding and bias, even a statistically significant small association might be inconclusive, because such associations could well be situated below reliable resolution levels of the "epidemiological microscope", i.e. it is not possible to discriminate between causation and bias/confounding ,23.Since most of the epidemiological studies before 2002 were performed in North America, and therefore primarily analyzed conjugated equine estrogens with or without MPA, we were interested in results for other HRT formulations more common in Europe; i.e. HRTs containing CEE were used by only 10% of our control and BC cases. Our register-based, case-control study showed marginally increased adjusted BC risk estimates of about 1.2 without variation with increasing lag time.A review of the literature shows that an increased risk of breast cancer is often but not always reported in studies ,13. In aSince HRT ever-use is a fairly crude summary indicator of exposure, it is advisable to look at time-related specifics such as duration of use and time since first and last exposures. We observed no significant trend toward risk with increasing duration of HRT use. Short-term use (under 2 years) and use of 8 and more years, however, was associated with a marginally significant increase in risk  showed also a slightly increasing risk with longer duration of HRT use via oral route, but not of transdermal administration . HoweverOur study confirmed that no increased BC risk or even decreased risk was associated with the use of estrogens alone. This fits in with the results of other studies ,27, whicThe BC risk for all combined HRT formulations was slightly higher and increased with longer duration. The risk was lower for sequential than for continuous-combined formulations. Several recent studies have found similar results but often with higher risk estimates ,26,36-38The BC risk associated with testosterone-derived progestins  seems – if taking the risk estimates at face value – to be slightly higher than with progesterone-derived progestins  on average but with a high variation at a low level of relative risk. However, to postulate a causal difference based on our study would be highly speculative – considering among others the fragile dataset of HRT formulation subgroups. It is far from clear, however, whether the apparently small difference in risk between progesterone- and testosterone-derived progestins is clinically meaningful. More general, it is debatable whether the apparent differences in BC risk across various progestins are real or simply chance findings due to multiple sub-analyses.The Million Women Study  and the In contrast, exclusive use of estrogens during lifetime seems not to be associated with an increased BC risk.Also, no evidence was found to confirm our initial hypothesis that conjugated equine estrogens co-formulated with MPA might be associated with a different risk as opposed to "natural estrogens" with or without MPA.More general, there is still uncertainty whether HRT use can really cause BC cancer induction de novo. A recent pathobiological review  made theThe cancer-register affiliated case-control study was based on voluntary participation. There are three main potential problem areas: self-selection, complex exposure biases, and recall bias. Although unlikely to differ across HRT formulation type, the self-selection of cases and controls to participate might be prompted by specific factors that affect the representativeness for the population. This cannot be excluded even for cases. Exposed subjects may have a higher likelihood of being selected into the study. The direction of this bias is unknown, because women might be motivated to participate either because they are particularly health-conscious, or because their health is poor, or because the used HRT, or for any number of other reasons.We assume that the results of our study have not substantially affected by self-selection. Moreover women without tumor may more readily answer "never used HRT" instead of "short use only" in case they used HRT only a very short period of time as opposed to tumor cases. This exposure misclassification would lead to overestimated tumor risk estimates for short-term use – what we indeed observed in our study. The effect overlaps with recall bias: Women with tumors might better recall exposure to HRTs because they were asked this question frequently in the course of diagnosis and treatment. Women without tumors might never have been questioned about their HRT use or may not even know what it means. This would tend to increase the tumor risk associated with HRT use. Since the BC risk estimates were relatively low, we think that these biases were not dominant in our study.Another potential source of bias is diagnostic suspicion bias. It cannot be assumed that tumor cases are equally identified (diagnosed) among HRT users and non-users. For instance, HRT users may be routinely advised by prescribing physicians to participate in screenings . Unfortunately, we could not control for the number of previous mammographies. This would lead to overestimated risk estimates. In addition, the possibility cannot be excluded e.g. that the women and/or their physicians were aware of "warning signs"  that may have led to the decision not to use HRT in the year prior to final BC diagnosis. This exposure indication bias may have worked differentially, i.e. more often in later confirmed cancer cases than in controls. Stratification by index dates (increasing lag times) would help to identify the effect of such a bias that was not observed in our study. In most of our analyses we chose to disregard exposure at least 6 month prior to diagnosis/interview. Other authors decided to lag exposure by one year for the same reasoning .An important paper was recently published closely related with this methodological discussion . The WHIWith regard to lifetime history of exposure, we were unable to compare mutually exclusive groups of different HRT formulations. Even if the hypothesis were acceptable that substantial differences in BC risk associated with different estrogens, progestins, and combinations would still be detectable despite dilution by overlapping exposure to different formulations during the lifetime, we cannot be certain. There is much room for speculation.Despite some advantages of our study over many others in considering time-dependent exposure during the lifetime, or in introducing different lag times to perform stratified analyses, we don't know the impact of the above-mentioned biases on the observed risk estimates. Our interpretation of the low BC risk estimates in our observational study and of the high potential for residual confounding and bias is that we cannot distinguish between causality and bias/confounding. In other words, the slightly increased BC risk estimates associated with HRT use might well be explained by bias and confounding despite all efforts to account for them. On the other hand, we cannot exclude a slightly increased risk of breast cancer associated with use of HRT either. In addition, we also cannot exclude a slightly higher BC risk for users of continuous-combined than of sequential formulation although the differences were small, i.e. possibly too small to be clinically relevant and too much room for bias to be causal.Taking the results at face value, ever-use of HRT is associated with a slightly increased risk of breast cancer. No significant trend of increasing BC risk with increasing duration of HRT use was observed in aggregate. There was, however, some evidence that the risk of BC might increase with longer use of some HRT formulation groups. Neither time since first use nor time since last use of HRT showed any association with BC risk. Many established BC risk factors significantly modified the effect of HRT on BC risk. Apparently, BC risk did not vary markedly among different HRT formulations . This should be interpreted with great caution because of mutually not exclusive HRT user profiles (subgroups) and small numbers. However, there might be differences that were not detectable in our study due to the "limited solution of the epidemiological microscope".We do not feel comfortable distinguishing between causal associations of BC risk and HRT use in our study and the effects of residual confounding and bias.A pharmaceutical company that produces HRT products financially co-sponsored this study.JCD: contributed to design the study, wrote the first draft of the manuscript, and was involved in the data analysis; LAJH: responsible for the design the study and prepared the data analysis plan, responsible for writing the manuscript; SM: responsible for the collaboration with the tumor centers and quality checks and management of the initial database, contributed to the manuscript; DMT: responsible for final data management and data analysis; contributed to the manuscript; AA: responsible for development of all questionnaires (together with SM), contributed to organizing field work and quality checks, contributed to the manuscript.The pre-publication history for this paper can be accessed here:


To evaluate the risk of endometrial cancer subsequent to breast cancer, a case-control study was carried out in Denmark. Between 1943-1977, 115 cases of histologically confirmed endometrial carcinoma developed more than 3 months after the diagnosis of a primary breast cancer in 51,638 women. A total of 235 breast cancer patients with no second primary cancer were matched to the cases on age, calendar year of diagnosis, and survival with an intact uterus. Identification of cases and controls relied upon records available in the Danish Cancer Registry. Information on risk factors and reproductive histories was abstracted from hospital records. Increased relative risks (RR) for endometrial cancer were associated with menopausal oestrogen use (RR = 4.9), nulliparity (RR = 2.1), late age at natural menopause (RR = 2.9), and pelvic irradiation (RR = 1.4). No association was apparent for drugs used to treat breast cancer. This study indicates that breast and endometrial cancer share several common aetiologic factors and that studies of second primary cancers have the potential to provide information on risk factors other than those associated with therapy.