(HealthDay News) — Oophorectomy is associated with a decrease in mortality in women with breast cancer and a BRCA1 mutation, and women with estrogen receptor-negative breast cancer and a BRCA1 mutation should undergo the procedure shortly after diagnosis, according to research published online April 23 in JAMA Oncology.
Researchers followed 676 women who had early-stage breast cancers and were carriers of BRCA1 or BRCA2 mutations. The women had received treatment for breast cancer, including mastectomy and lumpectomy. Roughly half had undergone an oophorectomy.
Overall, 77.4% of women survived over the 20-year follow-up from time of diagnosis, the findings showed. In women who underwent oophorectomy, the adjusted hazard ratio for breast cancer-specific mortality was 0.38 (95% confidence [CI], 0.19–0.77; P=0.007) for BRCA1 carriers and 0.57 (95% CI, 0.23–1.43; P=0.23) for BRCA2 carriers. For women with estrogen receptor-positive breast cancer, the hazard ratio for breast cancer-specific mortality was 0.76 (95% CI, 0.32–1.78; P=0.53), and for women with estrogen receptor-negative breast cancer, the hazard ratio was 0.07 (95% CI, 0.01–0.51; P=0.009).
On average, oophorectomy was done six years after the breast cancer diagnosis, but earlier oophorectomy conferred a greater reduction in breast cancer death risk. The protective effect of oophorectomy was especially strong if women had estrogen receptor-negative breast cancer after age 50.