Comparison of Survival Outcomes in Young Patients With Breast Cancer Receiving Contralateral Prophylactic Mastectomy Versus Unilateral Mastectomy

Abstract

BackgroundContralateral prophylactic mastectomy (CPM) has been performed for several decades in patients with unilateral breast cancer (BC). However, the survival benefits of CPM are controversial, particularly in young women. Materials and MethodIn this retrospective study, the clinical total of 69,000 young female patients (age ≤ 40 years) who were diagnosed to have unilateral BC and underwent unilateral mastectomy (UM) or CPM between January 1, 2000 and December 31, 2019 were retrieved from the Surveillance, Epidemiology, and End Results (SEER) database. Propensity score matching (PSM) was performed to minimize selection bias and overcome differences in tumor characteristics between the CPM and UM groups. Overall survival (OS) and BC-specific survival (BCSS) were assessed using Kaplan–Meier curves and compared across groups using log-rank test. Multivariable Cox proportional hazards regression analysis was performed to estimate hazard ratios (HRs). ResultsA total of 36,528 patients (21,600 and 14,928 patients in the UM and CPM groups, respectively) were included in follow study. The CPM group showed a higher 5-year OS rate (82.1% vs. 75.8%) and a higher 5-year BCSS rate (83.5% vs. 77.7%) than the UM group. Multivariate Cox analysis after PSM (n = 13,089) showed that CPM significantly decreased 25% risk of all-cause mortality (OS, HR: 0.75, 95% confidence interval [CI]: 0.70-0.80; P < .001) and 25% risk of BC-specific mortality (BCSS, HR: 0.75, 95% CI: 0.70-0.80; P < .001) in young BC patients as compared to UM. ConclusionThis study suggests that CPM improved OS and BCSS benefits in young BC patients as compared to UM. Randomized clinical trials with a larger sample size are required in the future to confirm these results.