Citations

PURPOSE BRCA carriers face high risks of developing both breast and ovarian/fallopian tube cancers (hereafter referred to as ovarian ). Among BRCA carriers with ovarian cancer, it is not clear whether the risk of breast cancer is sufficiently high that risk-reducing mastectomy should be offered. This study aimed to assess the risk of breast cancer BRCA carriers after a diagnosis of ovarian cancer. METHODS We included women with a pathogenic/likely pathogenic variant in BRCA1 or BRCA2 , a diagnosis of ovarian cancer, and no other cancer history and no risk-reducing bilateral mastectomy. Women were followed for incident breast cancer from the date of ovarian cancer diagnosis or the date of baseline questionnaire, whichever came last. The 5-, 10-, and 15-year cumulative risks of breast cancer were compared for women with ovarian cancer and an age-matched set of control women without ovarian cancer. RESULTS A total of 960 participants with ovarian cancer were identified (814 BRCA1 and 146 BRCA2 carriers). After a mean follow-up of 4.9 years, 41 women (4.3%) developed breast cancer, at a mean age at diagnosis of 57.5 years (range, 39-74). Actuarial cumulative breast cancer risks after ovarian cancer were 4.4%, 8.9%, and 11.5% at 5, 10, and 15 years, respectively. Only three breast cancer–related deaths occurred. Among 741 age-matched BRCA carriers without ovarian cancer, actuarial cumulative risks of breast cancer were 20.9%, 38.6%, and 47.2% at 5, 10, and 15 years, respectively. The hazard ratio for breast cancer, after an ovarian cancer diagnosis, compared with no ovarian cancer, was 0.18 ([95% CI, 0.12 to 0.27]; P < .0001). CONCLUSION After ovarian cancer, BRCA carriers have a relatively low risk of breast cancer. Risk-reducing mastectomy should not be recommended routinely, but might be considered for long-term survivors. Magnetic resonance imaging surveillance and/or mammography is a realistic alternative.

Abstract Background: The lack of consensus on whether bilateral oophorectomy impacts risk of developing breast cancer among BRCA1 mutation carriers might be attributed to various biases, specifically, cancer-induced testing bias due to inclusion of prevalent cases. We conducted two complementary matched case–control analyses to evaluate the association of oophorectomy and BRCA1 breast cancer. Methods: A research questionnaire was administered every two years to collect information on exposures and disease. In the first analysis, we limited the study to prevalent breast cancer cases (diagnosed prior to study entry; n = 2,962) who were matched to controls on year of birth and country of residence (n = 4,358). In the second approach, we limited to 330 incident cases (diagnosed in the follow-up period) and 1,548 matched controls. Conditional logistic regression was used to estimate the adjusted odds ratios (OR) and 95% confidence intervals (CI) of invasive breast cancer. Results: In the first approach, there was a significant inverse association between oophorectomy and the risk of developing breast cancer [OR = 0.43; 95% confidence interval (CI), 0.34–0.55; P &lt; 00001]. In the second approach, there was no association between oophorectomy and risk (OR = 1.21; 95% CI, 0.87–1.70; P = 0.26). Conclusions: The inclusion of women with a personal history of breast cancer prior to ascertainment likely impacts upon the association of oophorectomy and BRCA1 breast cancer risk. Impact: Oophorectomy is unlikely a determinant of breast cancer risk in BRCA1 mutation carriers but should be offered at age 35 to reduce the risk of ovarian and fallopian tube cancer.