Tamoxifen reduces the risk of benign breast disease

Tamoxifen appears to reduce the risk of benign breast disease and may result in fewer biopsies, according to an analysis of data from a major randomized clinical trial of tamoxifen. The findings appear in the February 19 issue of the Journal of the National Cancer Institute.

Tamoxifen was shown in the Breast Cancer Prevention Trial to reduce the incidence of invasive and noninvasive breast cancer by as much as 50% compared to placebo. Other studies have suggested that tamoxifen can also decrease the size of benign breast lesions, which have been associated with a modest increase in the risk for developing invasive breast cancer.

To examine the effect of tamoxifen on the risk of developing benign breast lesions, Elizabeth Tan-Chiu, M.D., of the Cancer Research Network in Plantation, Fla., and her coworkers from the National Surgical Adjuvant Breast and Bowel Project examined the incidence of benign breast disease among 13,203 women treated with either tamoxifen or a placebo as part of the Breast Cancer Prevention Trial. The authors also noted how many biopsies each group of women underwent.

Overall, tamoxifen treatment reduced the risk of benign breast disease by 28%. Women in the tamoxifen group were less likely to develop several types of benign diseases–adenosis, cysts, duct ectasia, fibrocystic disease, hyperplasia, and metaplasia–than women in the placebo group. Tamoxifen therapy also reduced the risk of fibroadenoma and fibrosis–two conditions that often result in biopsies. In fact, women in the tamoxifen group underwent 29% fewer biopsies than women in the placebo group. The authors note that the reduction in risk was mostly seen in women younger than age 50.

The authors conclude that, in the Breast Cancer Prevention Trial, “tamoxifen not only reduced the risk of invasive and noninvasive breast cancer but also reduced the risk of benign breast disease and the morbidity and costs of repeated diagnosis and treatment that are associated with it.”

They point out, however, that tamoxifen treatment carries risks, such as stroke and endometrial cancer, and they add that they do not advocate the indiscriminate use of tamoxifen for the treatment of benign breast disease.

Contact: Lori Garvey, National Surgical Adjuvant Breast and Bowel Project, 412-330-4621; fax: 412-330-4645, lori.garvey@nsabp.org

Tan-Chiu E, Wang J, Costantino JP, Paik S, Butch C, Wickerham DL, et al. Effects of tamoxifen on benign breast disease in women at high risk for breast cancer. J Natl Cancer Inst 2003;95:302–7.

Note: The Journal of the National Cancer Institute is published by Oxford University Press and is not affiliated with the National Cancer Institute. Attribution to the Journal of the National Cancer Institute is requested in all news coverage.