A Pilot Study of Male Breast Cancer in the Veterans Affairs Healthcare System

Abstract

We report our findings on a hospital-based retrospective pilot cohort with case-controls study, which we carried out to examine genetic, environmental, and occupational risk factors in men with breast cancer. 86 men with breast cancer were diagnosed in eight VA medical centers that agreed to collaborate on this project. A case-control analysis was conducted on a subset of the male breast cancer cases (n = 44) and age- and ethnicity-matched controls (n = 77). We compared host characteristics, comorbidities, and medications intake between cases and controls by using Chi-square analysis and Fisher's exact test. The descriptive analysis showed that the majority of veterans with male breast cancer were non-Hispanic white (60%), older than 65 years at diagnosis (56%), and more likely estrogen receptor positive (45%). World War II veterans represented the largest group (22%), followed by the Vietnam era veterans (10%). Thirty-three percent reported a positive family history of cancer, while 18% had another primary cancer diagnosis. Prior alcohol (43%) and tobacco use (56%) was substantial among these patients. Twenty percent of patients were overweight or obese and 55% had comorbid diseases with heart disease being the most prevalent, followed by diabetes mellitus. The case-control analysis yielded a significantly greater proportion of cases with gynecomastia (p < 0.0001), a positive family history of cancer (p = 0.0028), history of antibiotic use (p = 0.0112), and history of tobacco use (p = 0.0143) compared to controls. The findings of this hospital-based pilot study indicate case-control differences in gynecomastia and family history of cancer. The pilot study lacked sufficient power to determine a true association between the variables of interest and warrants a large-scale collaborative study between the VA medical centers.