Women 65 and older are less likely to survive breast cancer than their younger counterparts, two recent studies suggest.
The studies, published in the Journal of Clinical Oncology and the Journal of the American Medical Association, used previously collected data to study relationships between age and breast cancer outcome.
Background of Studies
Starting in the 1990s, breast cancer survival rates began to rise. These studies looked at whether those rates were uniform among different age groups. By finding differences, researchers can focus future study on those with greatest need.
Because more Americans are living longer, older people are of special concern. Risk of developing breast cancer increases with age, with about one-fifth of all U.S. breast cancer diagnoses in women over 75. Yet many older women cannot take part in or are excluded from clinical research, so we know little about the unique biology and challenges of breast cancer in this group.
Study 1: Age and Hormone-Sensitive Breast Cancers
This study looked at data from 9,766 women who took part in the Tamoxifen Exemestane Adjuvant Multinational (TEAM) clinical trial. Participants were postmenopausal and had early-stage, hormone-positive breast cancer. They were randomly assigned to take either five years of the aromatase inhibitor exemestane (Aromasin) alone or two to three years of tamoxifen, followed by two to three years of exemestane.
The original trial showed the two treatments worked equally well, so researchers believed the trial data could shed light on differences in breast cancer survival among three age groups: under 65, 65 to 74, and 75 or older.
After an average of 5.1 years, participants 65 and older were more likely to have died of breast cancer than those in the youngest age group. Older participants also were more likely than women under 65 to have had a breast cancer recurrence. These differences remained true even when researchers accounted for other issues that influence breast cancer outcome, such as tumor size and cancer traits.
Study 2: Age and All Breast Cancers
For this study, researchers compared the rate of breast cancer deaths in all Americans to the rate in people newly diagnosed with breast cancer. They gathered data from two large federal databases, National Vital Statistics and SEER. The analysis covered more than 219,000 women age 20 or older diagnosed with invasive breast cancer between 1980 and 1997. The researchers found:
- After 1990, women age 20 to 49 had the largest decrease in rate of breast cancer death, at 2.49 percent per year, compared to 1.14 percent per year for women 75 or older
- From 1980 to 1997, women 75 or older had a decrease in the absolute risk of breast cancer death after 10 years of just 7.5 percent; women 65 to 74 had a decrease in risk of 12.5 percent, and women 50 to 64 had a 15.3 percent drop in risk
Although future study is needed, the researchers said possible reasons for these differences in outcomes include:
- Differences in the biology of breast cancer in older people
- Doctors giving lower doses of chemotherapy because older people are more vulnerable to side effects
- Not taking hormonal therapies as prescribed
- Choosing treatments differently than other age groups because of concerns about quality of life and ability to live independently
- Taking non-cancer medicines that may interfere with the effectiveness of cancer treatment
What This Means for You
To get the most from your treatment, talk with your doctor or nurse about all medicines you take. Make a list before your appointments, and keep it up to date. Your providers, family or friends can help you write your list.
Take your treatment as prescribed, and talk with your care team or pharmacist if you’re having trouble doing so. They can help you think of ways to remember to take your medicines or manage side effects. If you are having trouble paying for treatment, they can also help you with resources.
Studies mentioned in this article:
BD Smith, et al. Improvement in Breast Cancer Outcomes Over Time: Are Older Women Missing Out? J Cl