Gender Disparity in Breast Cancer: A Veteran Population-Based Comparison.
Background: Male breast cancer (MBC) comprises <1% of all cancers and continues to rise. Because of rarity, there is paucity in the literature; therefore, management of MBC is generalized from female breast cancer (FBC).
Methods: Data from 152 VA Medical Centers were used to analyze the database of Veteran patient with breast cancer diagnosed between 1998 and 2016 using biostatistical software (SAS 9.3). Our primary objective is to compare patient's demographics, breast cancer characteristics, and outcomes for male and female Veterans. Finding: In total, 8864 patients' records were reviewed;1528 MBC were compared with 7336 FBC with a mean follow up time of 5.5 years (SD 4.17). The mean age at diagnosis was 68.6 years and 57.3 years for MBC and FBC, respectively (P < .0001). Higher numbers of MBC patients (95%) were >50 years of age compared to FBC patients (72%). More MBC patients (16.8 vs. 9.1% and 9 vs. 4%) presented with higher disease stage (III and IV, respectively). Estrogen receptor-positive tumors were more common in MBC (59 versus 52%). Hormonal treatment was received by 27% of MBC versus 19% FBC; chemotherapy 21.3% versus 41.5% and radiation 23.5% versus 60.9%. Forty-two percent MBC and 20% FBC Veterans died during study. Male patients had higher death rate 1.285 (95% CI: 1.150, 1.434, P < .0001) compared to females after adjusting data for age, race, stage, and grade. Interpretation: To the best of our knowledge, this is the largest comparison series of MBC and FBC to date in the Veterans population. The higher mortality rate in MBC patients may be due to late presentation, higher stage at the time of diagnosis and/or tumor biology. Veteran's exposures to hazardous materials during their military deployments as an additional factor for worse prognosis need further investigation.