2008 full free text: multinational study - Hormone Therapy and the Risk of Breast Cancer in BRCA1 Mutation Carriers - JNCI

Hormone Therapy and the Risk of Breast Cancer in BRCA1 Mutation Carriers -- Eisen et al. 100 (19): 1361 -- JNCI Journal of the National Cancer Institute

"In conclusion, these data are reassuring in suggesting that HT is probably not contraindicated in women with a BRCA1 mutation. Although the data cannot yet be considered definitive, we observed a statistically significant reduction in the risk of breast cancer following HT use, in both the unadjusted and adjusted analyses. It is important that these findings be replicated. The observed associations were not different for women who used estrogen alone or estrogen plus progesterone. There was little difference in the observed ORs associated with less than 3 years and 3 or more years of exposure, and therefore it is not possible for us to recommend an optimum duration of use. We did not include patients with BRCA2 mutations in this study because the sample size was small. It is important that these data be confirmed in other populations, including in women with BRCA2 mutations. It is also important to evaluate the other risks and benefits associated with HT use in women at high risk for breast cancer."

CONTEXT AND CAVEATS

Prior knowledge:
Use of hormone therapy (HT) after menopause may increase the risk of breast cancer in the general population. The effects of HT in women with mutations in the BRCA1 gene, however, are not known.

Study design:
Case–control study of postmenopausal women who carry a BRCA1 mutation to compare the risks of breast cancer among those who used HT and those who did not.

Contribution:
In this study of BRCA1 mutation carriers, a decrease in breast cancer risk was observed among those who took HT compared with those who did not.

Implications:
HT use does not appear to be associated with an increased risk for breast cancer among postmenopausal women who carry a BRCA1 mutation. Indeed, in this study, it was associated with a decreased risk among such women.

Limitations:
The study was relatively small, women who had undergone preventive mastectomy or used tamoxifen were excluded, and the results depended on the participants’ recall of HT use. An average of approximately 5.6 years had elapsed between breast cancer diagnosis and the completion of the questionnaire, so if BRCA1 mutation carriers who previously took HT have shorter survival after breast cancer diagnosis than those who did not take HT, this would have skewed the results in the negative direction that was observed.

From the Editors