Women with the BRCA 1 or 2 mutations may benefit from the use of tamoxifen, even if they are estrogen negative, but the evidence so far is not convincing. According to research in the Journal of Clinical Oncology, use of tamoxifen reduced the risk of cancer in the opposite breast by more than half among both BRCA1 and BRCA2 mutation carriers no matter what the receptor status was of the original tumor.
The study looked at information on 1,583 BRCA1 and 881 BRCA2 mutation carriers who took tamoxifen after their breast cancer diagnosis; of these 24 percent of the BRCA 1 took tamoxifen and 52 percent on the BRCA 2 carriers took tamoxifen.
This is an intriguing study and I would not make much of it until or unless a clinical study is started to look at the issue more closely in a more controlled environment. The numbers of women on tamoxifen were small in the research, because tamoxifen has not been recommended for TNBC and many cases of cancer among those with the BRCA mutations are TNBC. Also, we’re not sure how other variables were controlled, or if they were, so those could play a part. So I would not start thinking tamoxifen is a benefit to TNBC—there’s way too many questions right now, and the side effects of tamoxifen are significant. The general recommendation is not to use tamoxifen for TNBC, and that recommendation still stands.
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