The U.S. Preventive Services Task Force (USPSTF) has recommended that women with a high risk of breast cancer but who haven’t been diagnosed be offered medicines that can lower that risk.
The recommendations were published online on Sept. 24, 2013. Read “Medications for Risk Reduction of Primary Breast Cancer in Women: U.S. Preventive Services Task Force Recommendation Statement.”
The U.S. Preventive Services Task Force is a group of experts that makes recommendations to the U.S. Department of Health and Human Services on policies to prevent diseases. The task force reviewed many studies on medicines to reduce breast cancer risk to develop its recommendation statement. The recommendations are the same as the last statement released in 2002.
The recommendations say that doctors should offer the medicines tamoxifen and Evista (chemical name: raloxifene) to women aged 35 and older with a high risk of breast cancer who have never been diagnosed to reduce their risk. The task force didn’t recommend that women at average or low risk of breast cancer be offered these medicines.
Both Evista and tamoxifen are SERMs (selective estrogen receptor modulators). SERMs block the action of estrogen in breast and certain other cells by sitting in the cells’ estrogen receptors. SERMs don’t affect all estrogen receptors the same way because they’re selective (as the name says). In bone cells, SERMs interact with the receptors the way estrogen does and strengthen bones. In breast cells, SERMs block the receptors’ interaction with estrogen and limit cell growth.
Tamoxifen and Evista are pills taken by mouth.
In July 2013, the American Society of Clinical Oncology (ASCO) released new guidelines on using hormonal therapy medicines to reduce risk on postmenopausal women with higher-than-average risk. Besides tamoxifen and Evista, the ASCO guidelines recommend that doctors talk to high-risk postmenopausal women about using the aromatase inhibitor Aromasin (chemical name: exemestane) to reduce risk. Aromasin works by stopping the body from producing estrogen, which limits the amount of estrogen available to stimulate hormone-receptor-positive breast cancer cells to grow.
The hormonal therapy medicines don’t lower the risk of hormone-receptor-negative breast cancer.
Tamoxifen, Evista, and Aromasin all may cause side effects, some of them severe. Hot flashes and night sweats are side effects of all three medicines, though they’re more common with tamoxifen and Evista. Joint pain is a more common side effect of Aromasin. Aromasin also may weaken bones and make women more likely to break a bone. All three medicines can sometimes cause dangerous blood clots in rare cases. This complication is more common with tamoxifen and Evista.
Studies show the effectiveness of these medicines, but other research has found that they’re not widely prescribed by doctors or taken by women at high risk of breast cancer because of concerns about side effects.
Right now, most doctors use some form of the Gail model, a standard breast cancer risk assessment tool. The Gail model assesses breast cancer risk based on a series of personal health questions that women and their doctors answer together. The questions ask about risk factors such as age, child-bearing history, family history of breast cancer, and breast biopsy results. The result is a Gail score, which estimates the risk of developing invasive breast cancer in the next 5 years. Some more recent versions of the Gail model also include alcohol use, menopausal status, and body mass index. Some doctors wonder if genetic testing or other information should be added to the Gail model. More research needs to be done to figure out the most accurate way to assess a woman’s risk of breast cancer.
If you have a higher-than-average risk of breast cancer, it makes sense to do everything you can to keep your risk as low as it can be. There are lifestyle choices you can make, including:
- maintaining a healthy weight
- exercising regularly at the highest intensity possible
- limiting or avoiding alcohol
- limiting processed foods and foods high in sugar
- eating healthy, nutrient-dense food
- not smoking
You and your doctor also may be considering medicine to reduce your risk. Talk to your doctor about your preferences as well as the risks and benefits of each medicine. If you’re a postmenopausal woman and already taking tamoxifen or Evista and having unacceptable side effects, you may want to ask if Aromasin might be a better option for you. Together, you can make the best choice for your unique situation.
You can learn more about tamoxifen, Evista, and Aromasin in the Breastcancer.org Hormonal Therapy section.
Editor's Note: Research presented at the 2013 San Antonio Breast Cancer Symposium showed that Arimidex (chemical name: anastrozole) can lower the risk of first-time, hormone-receptor-positive breast cancer in postmenopausal women at high risk who haven’t been diagnosed. Arimidex isn’t approved by the U.S. Food and Drug Administration for this use, but doctors may consider it a good alternative to other hormonal therapies approved to reduce risk in high-risk women.