Chemoprevention for Women at High Risk for Breast Cancer

Zosia Chustecka

April 16, 2013

Chemoprevention with tamoxifen and raloxifene is now recommended for women at highest risk for breast cancer by the US Preventive Services Task Force (USPSTF), but is still not recommended for women at low or average risk.

This advice updates the 2002 recommendation, and comes in a draft recommendation published on the USPSTF Web site.

The draft recommendation is based on a systemic review published in the April 16 issue of the Annals of Internal Medicine, which concludes that there is broad benefit from these agents. Tamoxifen reduced the incidence of invasive breast cancer by 7 cases in 1000 women over 5 years, compared with placebo, and raloxifene reduced the incidence by 9 cases. Women at the highest risk for breast cancer and the lowest risk for adverse effects will benefit the most, as reported by Medscape Medical News.

In the draft recommendations, the USPSTF advises that for women at the highest risk for breast cancer, clinicians engage in shared decision making about medications to reduce their risk. For women at highest risk for breast cancer and at low risk for adverse effects related to the medication, clinicians should offer to prescribe a risk-reducing medication, such as tamoxifen or raloxifene.

These recommendations are category B, which indicates that there is "high certainty that the net benefit is moderate or there is moderate certainty that the net benefit is moderate to substantial."

Women are considered high risk if they have a family history of breast cancer, are 40 to 70 years of age, do not have signs or symptoms of breast cancer, and have never been diagnosed with breast cancer or ductal carcinoma in situ. However, women are excluded if they have a history of blood clots, including deep vein thrombosis, blood clots in the lung, strokes, and ministrokes.

"There are several serious harms associated with tamoxifen and raloxifene, which is why doctors must engage in a conversation with their patients and discuss the harms and benefits of these medications," said USPSTF member Wanda Nicholson, MD, MPH, MBA. "Because of these harms, the Task Force recommends against the use of these medications for women who are not at increased risk for breast cancer."

The USPSTF notes that its recommendation is consistent with advice issued by the American College of Obstetricians and Gynecologists and the American Cancer Society, and is consistent with accepted clinical practice.

The draft recommendation is open for public comment until May 13. The USPSTF notes that it will consider all public comments as it develops the final recommendation.


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