Study: Tamoxifen May Help Women With BRCA2 Gene Mutation

Tamoxifen may help prevent breast cancer in healthy women with the BRCA2 gene mutation but may not be helpful for women with the BRCA1 gene defect, according to researchers at the University of Washington, University of Pittsburgh and National Cancer Institute in Bethesda, Maryland.

In their study published in the Journal of the American Medical Association, investigators report that tamoxifen can reduce the risk of breast cancer by 62 percent in women with the BRCA2 mutation, a rarer mutation found in only 7 percent of the women studied.

Because BRCA2-linked tumors are estrogen-positive and BRCA1 tumors are estrogen-negative, tamoxifen is less effective in BRCA1 tumors, as tamoxifen inhibits the growth of cancer cells that are estrogen sensitive, according to the researchers.

Investigators analyzed blood samples from 288 women, ages 35 and older, who took tamoxifen or a placebo for five years. Only 19 of the women had BRCA1 or BRCA2 gene mutations. Three of the women in the study who had BRCA2 gene mutations who used tamoxifen developed breast cancer during the study, compared with 8 women who were taking a placebo.

Five women with the BRCA1 mutation taking tamoxifen developed breast cancer and three of the BRCA1 women taking a placebo developed the disease.

This study does not address the treatment of existing breast cancer with tamoxifen, which has been shown to be beneficial in helping to reduce tumor recurrence in women with estrogen-positive tumors who have BRCA1 or BRCA2 gene mutations, said the researchers.

Other Sources: Journal of the American Medical Association