NEW GUIDELINES FOR CHEMOPREVENTION OF BREAST CANCER

The US Preventive Services Task Force (USPSTF) has now issued final recommendations on chemoprevention for women at high risk for breast cancer in a report published onlineSeptember 24 in the Annals of Internal Medicine.

This final version follows an earlier draft of these recommendations, published in April alongside a systemic review of the literature, which found a "broad benefit" from prophylactic use of tamoxifen or raloxifene in women who had never had breast cancer.

Data from clinical trials showed that tamoxifen reduced the incidence of invasive breast cancer by 7 cases in 1000 women over 5 years, compared with placebo, and that raloxifene reduced the incidence by 9 cases. Both drugs also reduced the incidence of fractures, but both were associated with adverse events, including thromboembolic events, cataracts, and an increased risk for endometrial cancer.

The USPSTF recommends that clinicians "engage in shared, informed decision making for women who are at increased risk for breast cancer about medications to reduce their risk."

"For women who are at an increased risk of breast cancer and at low risk for adverse medication effects, clinicians should offer to prescribe risk-reducing medications, such as tamoxifen or raloxifene," the task force states. This is a grade B recommendation, which means there is "high certainty that the net benefit is moderate or there is moderate certainty that the next benefit is moderate to substantial."

However, routine use of these drugs in women who are not at increased risk for breast cancer is not recommended.

Recently, the American Society of Clinical Oncology also issued guidelines on chemoprevention for breast cancer, and recommended that tamoxifen and raloxifene "should be discussed as an option."

Also Recommended in Britain

Chemoprevention of breast cancer with tamoxifen and raloxifene is recommended for women in England and Wales who have a high risk for breast cancer in an updated guideline from the National Institute of Clinical Excellence.

Putting the recommendations into practice is another story, however. So far, there has been little use of chemoprevention for breast cancer, with few women who could benefit from this intervention choosing to take these drugs.

Ann Intern Med. Published online September 24, 2013. Full text