USPSTF updates guidelines on medication for breast cancer risk reduction

In an update of its 2002 recommendation on use of medications for breast cancer risk reduction, the U.S. Preventive Services Task Force (USPSTF) is encouraging informed decision-making and cautioning against use of medications for prevention in women who are not at increased risk of the disease.

Published in Annals of Internal Medicine, the new recommendations are based on a systematic review of evidence on the effectiveness and adverse effects of tamoxifen and raloxifene in reducing risk of breast cancer. They apply to women aged 35 and older with no prior diagnosis of breast cancer, ductal carcinoma in situ, or lobular carcinoma in situ.

The USPSTF Panel found adequate evidence that tamoxifen and raloxifene reduce incidence of invasive breast cancer by 7 to 9 events per 1000 women over 5 years, and the impact was greater for tamoxifen. The drug also fpimd tp reduce incidence of invasive breast cancer in premenopausal women at increased risk. Women with an estimated 5-year risk of  >3% are the most likely to benefit from risk-reduction medication.

However, both tamoxifen and raloxifene do carry potential risks. The drugs increased the likelihood of venous thromboembolism by 4 to 7 events per 1000 women over 5 years. Risk of endometrial cancer with tamoxifen was increased by 4 cases per 1000 women. Women aged 50 and older and those with a uterus were more likely to suffer from these adverse effects.

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