Trend and survival benefit of contralateral prophylactic mastectomy among men with stage I-III unilateral breast cancer in the USA, 1998-2016

Purpose Our study aimed to explore temporal trends and survival benefit of contralateral prophylactic mastectomy (CPM) in male breast cancer (MBC). Methods Men with stage I-III unilateral breast cancer between 1998 and 2016 were identified from the surveillance, epidemiology, and end results (SEER). We compared CPM rate over the study period using the Cochrane-Armitage test for trend. Logistic regression model was used to test for factors predicting CPM. Survival analysis was conducted in patients who underwent CPM or unilateral mastectomy (UM) with a first diagnosis of unilateral breast cancer. Kaplan-Meier curve and univariate and multivariable Cox proportional hazards regression analyses were performed to compare overall survival (OS) and breast cancer-specific survival (BCSS) between CPM and UM groups. Propensity score matching was adopted to balance baseline characteristics. Results 5118 MBC cases were included in the present study, with 4.1% (n = 209) patients underwent CPM. The proportion of men undergoing CPM increased from 1.7 in 1998 to 6.3% in 2016 (P < 0.0001). Young age, recent years of diagnosis, higher tumor grade and lower T stage were significantly associated with CPM. A cohort of 3566 patients were enrolled in survival analysis with a median follow-up of 65 months. CPM was associated with better OS (HR 0.58, 95% CI 0.37-0.89, P = 0.022) rather than BCSS (HR 0.57, 95% CI 0.29-1.11, P = 0.153) compared with UM. In propensity score-matched model, CPM was not an independent prognostic factor for OS (HR 0.83, 95% CI 0.46-1.52, P = 0.553) and BCSS (HR 0.98, 95% CI 0.39-2.47, P = 0.970). Conclusion Our study revealed a dramatic increase in CPM utilization among MBC, especially in young patients. However, CPM provides no survival benefit for MBC compared with UM, indicating the decision of CPM should be fully discussed.

Automated summary

This study aimed to explore the temporal trends and survival benefits of contralateral prophylactic mastectomy (CPM) in male breast cancer (MBC) patients between 1998 and 2016. The results showed a significant increase in CPM utilization, especially in young patients, but CPM did not provide a survival benefit compared to unilateral mastectomy (UM) in MBC patients.