Factors contributing to persistent rates of contralateral prophylactic mastectomy in breast cancer patients: Examination of 1051 mastectomies across a single health system

The American Society of Breast Surgeons (ASBrS) outlined definitive guidelines for contralateral prophylactic mastectomy (CPM) in 2016. Despite this, rates of CPM have remained steady. The objective of this study was to identify factors contributing to persistent over-delivery of CPM. Breast cancer patients across 8 hospitals in a single healthcare system from 2014 to 2018 were retrospectively reviewed. The patients were divided according to whether they received nonindicated CPMs versus other mastectomy types. Nonindicated CPM were those procedures not meeting ASBrS consensus guidelines for recommended patients. CPM rate was calculated for each year in the study period. Patient, disease, provider, and system level factors were obtained. Bivariate analysis was used to identify variables for inclusion in a backward multivariable model. A total of 1,051 patients were analyzed. Nonindicated CPM rates by year remained steady throughout the time period (P = .391). In multivariable regression, patient, disease, and provider level factors were associated with odds of undergoing CPM. Every unit increase in age was associated with a 4% reduction in odds of undergoing CPM (CI 0.941-0.986). Stage 3 breast cancer compared to stage 1 had 53% lower odds of CPM (CI 0.288-0.757). Implant-based breast reconstruction had 2.9-fold higher odds of CPM compared to no reconstruction (CI 1.476-5.551). No system level factors were statistically significant. CPM rates have not notably decreased since the ASBrS consensus statement with certain patient and provider factors impacting persistent overuse of CPM. These results inform oncologic and reconstructive providers of factors contributing to continued use of a nonindicated procedure.