1509 Background: Contralateral risk-reducing mastectomy (CRRM) reduces contralateral breast cancer (BC) risk by up to 97%. Few studies have examined the prevalence and predictors of CRRM in BC patients at high familial risk of a second primary BC. Methods: Participants were women with unilateral BC and a strong family history of the disease, including BRCA1 and BRCA2 mutation carriers. Data were collected by interview, self-administered questionnaire, and review of pathology and surgical reports. Associations between having CRRM and potential predictors were assessed using multivariate logistic regression. Results: Of 1018 study participants (median follow-up 5.5 years), 154 (15%) underwent CRRM. The median time from initial BC to CRRM was 1 year. More likely to undergo CRRM were women who were younger at the time of their BC diagnosis (odds ratio [OR] = 0.94 per year of age, p < 0.001), those diagnosed more recently (OR = 1.16 per calendar year, p < 0.001), those who underwent mastectomy rather than breast conservation as their initial definitive BC treatment (OR = 5.2, p < 0.001) and those who underwent risk-reducing salpingo-oophorectomy (OR = 3.4, p < 0.001). BRCA1/2 mutation status and tumor characteristics were not independently associated with CRRM uptake. A contralateral BC event occurred in 177 (20.5%) of the 864 women who did not have CRRM, compared with one chest wall event (0.6%) in the 154 women post-CRRM. Conclusions: Younger women with more recently diagnosed BC treated with mastectomy were most likely to elect CRRM. BRCA1/2 mutation status and the competing risk of BC recurrence and death did not appear to influence decision making. No significant financial relationships to disclose.
Reproductive factors and risk of contralateral breast cancer by BRCA1 and BRCA2 mutation status: results from the WECARE study
