Contralateral Prophylactic Mastectomy among Women with Pathogenic Variants in : Overall Survival, Racial, and Ethnic Differences.

Background: Patients with unilateral breast cancer carrying pathogenic variants in have the option to undergo contralateral prophylactic mastectomy (CPM). However, differences in CPM use and survival outcomes following CPM are poorly understood in this high-risk population, in part due to a lack of data from contemporary clinical cohorts. The objective of this study was to evaluate post-CPM overall survival (OS) and related racial/ethnic differences in a contemporary clinical cohort.

Methods: We retrospectively reviewed the medical records of women with a personal history of unilateral breast cancer carrying pathogenic variants in who were diagnosed between 1996 and 2012. Genetic test results, self-reported demographic characteristics, and clinical factors were abstracted from electronic medical records.

Results: Of 144 BRCA-positive patients, the majority were White (79.2%,  = 114). Overall, 56.1% ( = 81) of all carriers chose to undergo CPM, with no racial/ethnic difference in CPM election ( = 0.78). Of 81 patients who underwent CPM, there is strong evidence of a difference in survival between the racial/ethnic groups, with White patients having the highest OS compared to non-White patients ( = 0.001). Of the 63 patients who did not undergo CPM, there is no racial/ethnic difference in overall survival ( = 0.61). In multivariable cox regression, adjusted for demographic and clinical characteristics, OS was significantly lower among non-Whites than in Whites (HR = 0.39,  = 0.04).

Conclusions: Evaluation of a contemporary clinical cohort of BRCA-positive women with unilateral breast cancer showed no racial/ethnic difference in CPM use, but there was a significant difference in post-CPM overall survival.