Abstract
BACKGROUND: Breast cancer is rare in men. This population-based study aimed to determine outcomes of male breast cancer in relation to residence and other variables. METHODS: In this retrospective cohort study, men diagnosed with breast cancer in Saskatchewan during 2000-2019 were evaluated. Cox proportional multivariable regression analyses were performed to determine the correlation between survival and clinicopathological and contextual factors. RESULTS: One hundred-eight eligible patients with a median age of 69 years were identified. Of them, 16% had WHO performance status ≥ 2 and 61% were rural residents. The stage at diagnosis was as follows: stage 0, 7%; I, 31%; II, 42%; III, 11%; IV, 8%. Ninety-eight percent had hormone receptor-positive breast cancer. The median disease-free survival of urban patients was 97 (95% CI: 50-143) vs. 64 (46-82) months of rural patients (p = 0.29). The median OS of urban patients was 127 (94-159) vs. 93 (32-153) months for rural patients (p = 0.27). On multivariable analysis, performance status ≥ 2, hazard ratio (HR) 2.82 (1.14-6.94), lack of adjuvant systemic therapy, HR 2.47 (1.03-5.92), and node-positive disease, HR 2.32 (1.22-4.40) were significantly correlated with inferior disease-free survival in early-stage invasive breast cancer. Whereas stage IV disease, HR 7.8 (3.1-19.5), performance status ≥ 2, HR 3.25 (1.57-6.71), and age ≥ 65 years, HR 2.37 (1.13-5.0) were correlated with inferior overall survival in all stages. CONCLUSIONS: Although residence was not significantly correlated with outcomes, rural men had numerically inferior survival. Poor performance status, node-positive disease, and lack of adjuvant systemic therapy were correlated with inferior disease-free survival.