Poorer Survival of Male Breast Cancer Compared with Female Breast Cancer Patients May Be Due to Biological Differences

Objective: The objective of the study was to compare disease-free survival and overall survival in a group of matched males and females with breast cancer, and to analyze possible treatment- and gender-related differences. Methods: We retrospectively analyzed the data of 150 operable male breast cancer patients treated in our hospital from December 1980 to June 2012. Each male breast cancer patient recorded in the database was matched with two female breast cancer patients of equal stage. Prognosis in terms of disease-free survival and overall survival was evaluated. Results: The mean age at diagnosis was 58.6+9.7 years for males and 57.2+10.3 years for females. The median follow-up was 69 months for males and 81 months for females. Significant differences were identified for tumor location, hormone receptor status, molecular subtypes and hormone therapy between the two groups. Monofactorial analysis demonstrated that tumor size, lymph node state, American Joint Committee on Cancer stage, molecular subtypes and adjuvant chemotherapy treatment were prognostic factors in male breast cancer patients. The 5- and 10-year disease-free survival rates were 65.6 and 40.1% for males, and 74.9 and 51.5% for females, respectively. The 5- and 10-year overall survival rates were 72.9 and 53.9% for males, and 83.2 and 68.5% for females, respectively. There was significantly difference in disease-free survival and overall survival between the two matched groups (P ¼ 0.002). Conclusions: Male breast cancer patients had inferior outcome despite of equal stage in comparison with matched female breast cancer patients, which demonstrates that biological differences may contribute to the worse prognosis.