Breast Conservation Surgery for Breast Cancer in Men.

Background: Male breast cancer (MBC) is a rare disease, accounting for 1% of all breast cancers diagnosed in the United States. The rarity of MBC has limited the development of treatment algorithms specific to men. Thus, the standard of care has been mastectomy. The safety and feasibility of breast-conserving surgery (BCS) in MBC are unclear. This study assessed whether overall survival outcomes, local recurrence, and postoperative complications differed between MBC patients who underwent conservative surgery or mastectomy.

Study Design: A retrospective search for men aged ≥18 years diagnosed with breast cancer was conducted using the TriNetX network. Cohort 1 included patients who underwent BCS. Cohort 2 included patients who underwent mastectomy. Propensity score matching was conducted using age, BMI, tobacco use, cancer stage and tumor size (T1-T4), radiation, chemotherapy, hormonal therapy, genetics, and comorbidities. Outcomes of interest were 5-year overall survival (OS), local recurrence (LR), and postoperative complications.

Results: 423 patients underwent BCS, and 1,101 patients underwent mastectomy. After matching, 401 patients per cohort were identified. There was no difference in 5-year OS with the Kaplan-Meier analysis (Cohort 1: 84% vs Cohort 2: 86%, log-rank test p=0.412) or with LR (11% vs 13%, p=0.384). The mastectomy cohort was more likely to have postoperative complications, with a risk of 24% compared with 17% in the BCS cohort (p=0.011).

Conclusions: There is no difference in the 5-year OS and LR rate between MBC patients who undergo BCS or mastectomy. The postoperative complication rate was higher with mastectomies. We conclude that BCS for unicentric male breast cancer is feasible and preferred for T1 and T2 cancers.