Cancer Preventive Rx Too Risky for Most

Breast cancer risk reduction medications not recommended for average risk women

/ Author:  / Reviewed by: Joseph V. Madia, MD Beth Bolt, RPh

(RxWiki News) Women who are at high risk of developing breast cancer may be prescribed risk-reducing medications. Because some of these medicines have serious side effects, recommendations regarding who should take them have changed.

The US Preventive Services Task Force (USPSTF) announced that it does not recommend routine use of tamoxifen (brand names Nolvadex, Soltamox, Tamofen, Tamoxen) and raloxifene (Evista) to reduce breast cancer risks in women who don’t have elevated risks for the disease.

The USPSTF further recommends that physicians should carefully review the risks and benefits of these medications in women who have higher risks of breast cancer because of family history or other factors.

Clinicians should offer risk-reducing medications to women who have a five-year breast cancer risk of 3 percent or higher and who have low risks of harmful medication side effects, the USPSTF now recommends.

"Find out the exact nature of your cancer risks."

The new USPSTF recommendation is an update of a 2002 recommendation on the use of medication to reduce breast cancer risks.

The recommendation comes after the group conducted a systematic review of clinical trials and reviewed 13 breast cancer risk assessment models. The group also looked at a meta-analysis of all trials on the relative benefits and harms of tamoxifen and raloxifene.

These two medications have been shown in randomized, controlled trials to reduce the risks of breast cancers driven by the hormone estrogen. Both medications work to block estrogen activity.

Studies found that over a five-year period, tamoxifen and raloxifene reduced invasive breast cancer by seven to nine cases per 1,000 women.

Tamoxifen reduced a greater number of breast cancer cases than did raloxifene. Tamoxifen also reduced the incidence of breast cancer in high-risk premenopausal women, the meta-analysis found.

Risks of non-vertebral fractures were reduced by tamoxifen, and raloxifene reduced the risks of vertebral fractures.

Those were the benefits of these two medications.

In terms of potential harms, both medications increased the risk for venous thromboembolic events (VTEs) — blood clots that form in the veins of the legs or pelvis that can break off and cause strokes. The medicines have been linked to 4 to 7 VTE events per 1,000 women over five years.

Tamoxifen also increased the risk of endometrial cancer by four cases per 1,000 women.

Risks of cataracts were higher in women who took tamoxifen.

Both medications were associated with hot flashes.

Breast cancer risks include: increasing age, race/ethnicity (African-American women are at higher risk than white women), age at first period and childbirth, first-degree (mother, sister, child) relatives with breast cancer, personal history of breast biopsy, ductal carcinoma in situ or lobular in situ, body mass index (BMI; amount of body fat), age at menopause, breast density, hormone replacement therapy use, smoking and alcohol use history, physical activity and diet.

Women who have a personal history of breast cancer, have had radiation treatment to the chest or may carry mutations in the BRCA genes are at high risk of developing breast cancer.

Adam Brufsky, MD, PhD, professor of medicine at the University of Pittsburgh, told dailyRx News, “This is what a lot of us are doing at this time. It is important that women be counseled with the correct figures for absolute risk reduction of breast cancer as well as absolute risk of side effects when making a decision to start a preventive therapy like this.”

The new USPSTF recommendations were published September 23 in the Annals of Internal Medicine.

Review Date: 
September 23, 2013
Last Updated:
September 24, 2013