Women at high risk of breast cancer should discuss with their doctors the use of so-called chemopreventive drugs to reduce that risk, according to a new practice guideline issued by the American Society of Clinical Oncology.
The guideline updates one issued in 2009, said Dr. Kala Visvanathan, director of the clinical cancer genetics and prevention service at the Johns Hopkins Sidney Kimmel Comprehensive Cancer Center, who co-chaired the guidelines panel.
"It's a stronger recommendation for discussion of these agents," she said. The new guideline also adds another drug option for breast cancer risk reduction.
The guideline was published online in the Journal of Clinical Oncology.
The key points include a recommendation to discuss the use of tamoxifen (Nolvadex, Tamofen, others) with premenopausal women at high risk, and tamoxifen and raloxifene (Evista) with postmenopausal women. The guideline adds another alternative, exemestane (Aromasin), for postmenopausal women.
Visvanathan and other panel members looked at 19 published articles to assess the use of the drugs to reduce breast cancer risk.
The panel recommended various doses of the drugs, taken daily for five years, to reduce risk. Tamoxifen and raloxifene target estrogen receptors and work to reduce the risk of estrogen receptor-positive, or ER-positive, cancers, which need estrogen to grow.
Exemestane lowers the amount of estrogen in the body. It is not yet approved by the U.S. Food and Drug Administration for breast cancer prevention, but a study has found it can reduce risk by up to 70 percent over three years.
The guideline is meant for women who are cancer-free but at high risk for breast cancer, Visvanathan said. "We aren't talking about breast cancer survivors and we aren't talking about all women," she said. The guideline recommends only discussing the drugs with a doctor, not that women at high risk should absolutely take them, she added.
Women should talk about the risks and benefits of the drugs to reduce breast cancer risk and then decide, she said.
Who might fit this profile of high risk? A woman in her 40s who has a condition called atypical hyperplasia, an abnormality in breast cells that has been linked to higher risk of breast cancer, should discuss the use of the drugs, Visvanathan said. So should a woman in her 50s with a family history of breast cancer and who has never given birth.
Women with the BRCA1 and BRCA2 gene mutations, known to boost breast cancer risk, should also discuss the drugs with their doctor, she said, "although they have other preventive options as well."