ASCO updated guideline on pharmacologic interventions for breast cancer risk reduction

Guideline updated for pre- and postmenopausal women.

The American Society of Clinical Oncology recently updated its clinical practice guideline on breast cancer risk reduction. The updated guideline states that postmenopausal women who are at an increased risk for breast cancer could benefit from taking tamoxifen or raloxifene.

The guideline was updated based on data from relevant randomized trials published since 2002. Breast cancer incidence was the primary outcome of interest; secondary outcomes of interest were breast cancer mortality and adverse events. An expert panel updated the guidelines to reflect these findings.

For women at increased risk for breast cancer, tamoxifen 20 mg/day for five years is recommended to reduce the risk for invasive ER-positive breast cancer for at least 10 years. It is noted in the recommendation that there is no known benefit to taking tamoxifen for longer than five years.

The newly updated guideline also states postmenopausal women with an elevated risk for breast cancer may help reduce their risk with raloxifene 60 mg per day for five years. Formerly, the guideline recommended only tamoxifen for breast cancer risk reduction among these women.

Additionally, according to study findings reviewed by the expert panel, the risk for thromboembolic disease, benign uterine conditions and cataracts was lower in patients assigned raloxifene vs. tamoxifen. Also, postmenopausal women with osteoporosis, in whom reducing breast cancer risk is a secondary benefit, may use raloxifene for longer than five years.

“Women taking these drugs will need to consider both the benefits and adverse effects of each agent,” Kala Visvanathan, MD, MHS, assistant professor, John Hopkins Bloomberg School of Public Health and School of Medicine, said in a press release.

Visvanathan stressed the importance of women discussing their options with their health care providers.

Long term follow-up information on the risks and benefits of tamoxifen-use for breast cancer risk reduction was provided within the guidelines. According to the guideline, raloxifene was not recommended for premenopausal women, and women with history of blood clot or stroke should not take raloxifene or tamoxifen.

Another important aspect of the guideline is the recommendation against the use of aromatase inhibitors or retinoids, outside of a clinical trial, to reduce the risk for breast cancer.

Finally, Visvanathan stressed the importance of calculating breast cancer risk in all women periodically due to increasing lifelong risk and the need for health providers to give women at increased risk the opportunity to consider available risk reduction options. The National Cancer Institute’s Breast Cancer Risk Assessment Tool defines which women have an elevated risk for developing breast cancer using a woman’s age, race and medical history.

Tools and resources, such as the decision aid tool which helps explain the risks and benefits of breast cancer chemoprevention using charts and diagrams, are available on the ASCO website.