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The impact of oophorectomy on survival after breast cancer in BRCA1 and BRCA2 mutation carriers.
J Clin Oncol 32:5s, 2014 (suppl; abstr 1507)
Abstracts that were granted an exception in accordance with ASCO's Conflict of Interest Policy are designated with a caret symbol (^).
Background: Oophorectomy is often recommended to women with BRCA-associated breast cancer in order to prevent a second primary breast cancer and ovarian cancer. However, it is unclear if oophorectomy has an impact on survival in women with BRCA-associated breast cancer. The objective of the current study was to estimate the impact of oophorectomy on survival from breast cancer for women with a BRCA1 or BRCA2 mutation Methods: 760 women with Stage I or Stage II breast cancer and a BRCA1 or BRCA2 mutation, between the ages 25 and 65, were followed for up to 20 years from diagnosis. The impact of oophorectomy on survival was evaluated in a Cox proportional hazards model, adjusting for age, gene (BRCA1 versus BRCA2), tumour stage, ER status and other treatments. Results: Of the 760 women, 455 had an oophorectomy, either prior to or after the diagnosis of breast cancer. The 20-year survival for the entire patient cohort was 74.3%. The un-adjusted hazard ratio for death associated with oophorectomy was 0.62 (95% CI: 0.42 to 0.90; p = 0.01) and the adjusted hazard ratio was 0.66 (95% CI 0.42 – 1.02; p = 0.06). The hazard ratio was 0.59 (95% CI: 0.34 – 1.01; p = 0.05) for BRCA1 carriers and was 0.81 (95% CI: 0.35 -1.85; p = 0.61) for BRCA2 carriers. The adjusted hazard ratio was 0.77 (95% CI 47 – 1.28; p = 0.29) for women diagnosed under age 50 and was 0.38 (95% CI: 0.12 to 1.15; p = 0.09) for women diagnosed over age 50. The hazard ratio was 1.21 (95% CI: 0.55 to 2.67; p = 0.65) for women with estrogen receptor-positive breast cancer and was 0.27 (95% CI: 0.11 to 0.67; p = 0.005) for women with estrogen receptor-negative breast cancer. Conclusions: Oophorectomy is associated with a decrease in mortality in women with early-stage breast cancer and a BRCA1 mutation. Women with estrogen receptor-negative breast cancer and a BRCA1 mutation should consider oophorectomy shortly after diagnosis as part of their treatment plan.