Male breast cancer (MBC) in the VA population: A gender issue?

Abstract

587 Background: The incidence of MBC continues to rise. Few studies have addressed the differences between MBC and female breast cancer (FBC). Treatment for MBC has ben extrapolated from FBC regimens. The VA cancer registry (VACCR) provides a unique source to study MBC. This retrospective analysis aims at comparing the characteristics and outcome of MBC and FBC in the VA population. Methods: We reviewed the VACCR database between 1995 and 2005, for 120 VA medical centers. Primary breast cancer site codes were identified (500–508). Data was entered and analyzed using bio-statistical software SPSS. Results: A total of 3025 patients :612 MBC and 2413 FBC were compared. Mean age at diagnosis was 67 for MBC and 57 for FBC (p <0.005). More MBC patients were black. MBC patients presented with a significantly higher stage of disease, more node positive(N+) and larger tumor size. In MBC, ductal histology was more common while lobular and ductal carcinoma in situ were less common than in FBC. ER + and PR + tumors were significantly more common in MBC (60% vs 52% and 53% vs 47%, P< 0.005). MBC patients received less chemotherapy while no statistical difference in hormonal treatment was observed. The median overall survival (OS) was lower for MBC (7 years vs 9.8 years, p<0.005). OS was not significantly different for stage III and IV while OS was inferior for MBC in stage I (7 yr vs not reached, p 0.005) and stage II (6 vs 8.6yr, p 0.001). In N- tumors, OS was inferior in MBC (6.1 vs 14.6 yr, p<0.005) but not statistically different for N+ tumors . In ER + and PR + tumors, OS was inferior in MBC (7yr vs 8yr and 7.3 yr vs 9.8 yr p<0.005); however, no statistical significance was observed in ER - or PR - tumors. Using Cox regression analysis age, sex, clinical stage, nodal status were statistically independent prognostic factors while race, histology and grade were not. Conclusion: This study suggests differences in the biology, pathology, presentation, and survival between male and female VA breast cancer patients. Survival of MBC patients appears inferior in early stage disease and N- tumors suggesting gender differences in the tumor pathogenesis and biology. In hormone receptor + MBC, survival was also inferior despite similar hormonal treatment practices. This observational study calls for different approach and treatment strategies in MBC. No significant financial relationships to disclose.