"Every year many U.S. women get the grim news that they have breast cancer. In  alone according to the American Cancer Society more than  http were given that diagnosis. Each one very likely came as a devastating blow both to the patient and to her family. But what if some of these cases are preventable What if there was a medication that could at least reduce a womans risk of developing breast cancer Such drugs already exist. The Breast Cancer Prevention Trial published results http in  indicating that women who took one of those drugs tamoxifen were half as likely to develop breast cancer as similar women who did not take the drug. Other medications including raloxifene httpen.wikipedia.orgwikiRaloxifene and a class of drugs called aromatese inhibitors httpformularyjournal.modernmedicine.comformularyjournalcontenttagsaromataseinhibitorguidelineaddsaromataseinhibitorbreastcancepagefull do much the same thing though the Food and Drug Administration has not yet approved aromatese inhibitors for this use http Studies estimate httpjnci.oxfordjournals.orgcontent.full that more than  million American women at high risk for breast cancer could benefit from taking a preventive drug. But few women are opting for this protection which goes by the name chemoprevention. A  study found exceptionally low rates of usage. In part this may be because many doctors are not even discussing this option with their patients. A small  study http in the Journal of Womens Health found that only  percent of internal medicine family medicine and gynecology physicians reported having recommended or prescribed these medications to women who might benefit from them. The low uptake of these medications is a missed opportunity says Heidi Nelson a professor of medical informatics and clinical epidemiology at the Oregon Health  Science University in Portland. Many highrisk women ... could reduce their risks for invasive cancer by approximately  to  percent. On the other hand these drugs dont suit everyone and they are not without risks of their own. Because some of the side effects are serious  such as blood clots in the legs and in the lungs and in the case of tamoxifen uterine cancer  only women who are deemed to be at high risk for the disease should consider them. But there are conflicting views on who meets that high risk definition A bit about the drugs Chemoprevention should not be confused with chemotherapy. Although both involve taking drugs chemoprevention medications are taken with the goal of avoiding breast cancer altogether and the subsequent need for chemotherapy later. And they work on the body differently. Chemotherapy kills off cells healthy ones as well as cancercous ones. The chemoprevention drugs by contrast work by blocking estrogen a hormone known to promote the growth of cancer cells in breast tissue. Chemoprevention drugs are called SERMs or selective estrogen receptor modulators and two have been approved specifically for breast cancer prevention tamoxifen which was developed to treat breast cancer after its onset and only later was found to have a preventive benefit and raloxifene which was designed to treat osteoporosis. A  study http in the Lancet analyzed data for more than  women taking tamoxifen or other SERM drugs. The researchers found an overall  percent reduction in new cases of breast cancer  years after women took these drugs compared with women who took a placebo. The effect was even larger during the first five years of the study. Investigators working for the U.S. Preventive Services Task Force an independent group of scientists and clinicians funded by the government echoed these results. After looking at multiple trials of tamoxifen and raloxifene the task force noted http that these drugs reduced new cases of breast cancer significantly from  cases per  women in the control groups to  cases per  women in the treatment groups.  Nelson one of the lead authors of the analysis is confident that these results show a true benefit. Others are more cautious. Kenneth Lin a family physician at Georgetown University who worked on developing the task forces SERM guidelines notes that while SERMs may have reduced new cases they have not been shown to reduce breast cancer mortality in any study or metaanalysis. One possible explanation he says is that these drugs are effective at preventing nonlethal cancers rather than the more serious ones. Not used enough Given that these drugs seem to offer some protection why are they not in widespread use Serious side effects is one reason. Beyond blood clots and uterine cancer other known reactions to the drugs include strokes cataracts bone pain hot flashes nausea and vaginal dryness. For some women the risk of such side effects may be worth taking depending on their particular odds of developing breast cancer. Those odds can be figured by using a commonly used calculator http often called the Gail model that estimates a womans chances of having breast cancer in a fiveyear period and over a lifetime. But this is where it gets more complicated. While many experts agree that women at high risk should consider the medications they do not agree on what Gail score should trigger that consideration. The studies that served as the basis for the FDA approval of the drugs along with recently released guidelines httpjco.ascopubs.orgcontentearlyJCO....full.pdf from the American Society of Clinical Oncology ASCO set the threshold at a fiveyear Gail score of . percent. The Preventive Services Task Force however recommended a threshold of  percent. At that point the panel said http women are likely to have more benefit than harm from using tamoxifen or raloxifene. ASCOs lower cutoff worries some experts. At the . percent highrisk threshold Georgetowns Lin says every woman age  and older would be considered highrisk. That might lead to a situation in which millions of women would be encouraged unnecessarilyto consider this therapy along with its potential harmful effects. Starting a conversation Kala Visvanathan the lead author of the ASCO recommendations and a faculty member at the Johns Hopkins School of Medicine said the cutoffs provide only a rough estimate of risk. It is important to realize she adds that as the risk increases the benefits tend to be greater. This is an evolving field and our goal is to better discern who is at high and low risk of breast cancer and develop a greater range of prevention strategies. An individual risk analysis should prompt conversation between doctor and patient about the potential benefits and the risk of the therapy. Both the ASCO and the task force guidelines recommend such a conversation. The discussion should include the specific risks and benefits associated with each chemopreventive agent according to ASCO. The task force similarly recommends that clinicians engage in a shared informed decision making with women and said that clinicians should offer to prescribe these drugs. Many risk factors increase a womans chances of having side effects. These factors include older age obesity having a history of a blood clot history of any cancer immobility history of certain autoimmune conditions history of using estrogen or oral contraceptives and history of some form of heart disease. Insured women with a high risk for breast cancer and a low risk for side effects who try this therapy will not incur outofpocket costs because this treatment was included in the Affordable Care Act as mandated nocharge preventive care. So what should a woman do Most important become familiar with your family history know your risk factors and discuss them with your primarycare physician. Age and family history cannot be controlled but lifestyle changes  including eating a healthful diet exercising not smoking and not overconsuming alcohol  are eminently doable and can reduce your risk. These basic tenets of leading a healthy lifestyle http have been shown to be important factors in breast cancer prevention. Visvanathan and her colleagues are hopeful that more women will be aware of this option. A discussion on the use of preventive agents needs to become part of routine care in women at high risk she says. We should begin to implement preventive strategies based on what we already know. Mishori is an associate professor of family medicine at the Georgetown University School of Medicine and director of the Health  Media fellowship. Seliby is a family physician and the Health  Media fellow at Georgetown University School of Medicine."