Examining racial disparities in male breast cancer.

6555 Background: Male breast cancer (MBC) accounts for approximately 1% of all breast cancers. Racial disparities have not been examined in MBC. Methods: Within a large, integrated health delivery system, all adult female and male patients who were diagnosed with breast cancer from 01-01-2010 to 12-31-2018 were examined. Bivariate analysis was performed to examine clinical and demographic factors associated with breast cancer-related mortality. We conducted more detailed chart review in the MBC-only group (data period 01-01-2010 to 12-31-2019) to assess the mean time to treatment (from diagnosis to surgery, surgery to chemotherapy, and surgery to radiation) stratified by race using bivariate (t-test, one way ANOVA) analyses. Results: 32,848 female breast cancer and 226 MBC patients were evaluated; MBC patients represented 0.63% of all breast cancer patients. Between males and females, there was no statistically significant difference in race, with an overall distribution of 62% White, 19% Asian, 8% Black, and 11% Hispanic. To our knowledge, this is the largest and most racially diverse sample of MBC patients to date. MBC patients at diagnosis were significantly older (p <.0001), more obese (p < 0.0018), and sicker according to the Charlson Comorbidity Index (CCI) (p < 0.0001) compared to female breast cancer patients. Males were more likely to be diagnosed at an advanced stage (19.2%) compared to females (12.5%) (p = 0.0037). With a mean follow up of 5 years, overall mortality was statistically significantly worse in MBC (23.0%) compared to female breast cancer patients (12.0%) (p < 0.0001). Furthermore, breast cancer-related mortality was significantly higher in males (8.1%) than in females (4.5%) (p = 0.0124). In the MBC-only analysis, stage at diagnosis was not influenced by patient race. Asian and White MBC patients had the shortest mean time from diagnosis to surgery (27 and 29 days, respectively), with Hispanic MBC patients experiencing the longest time to surgery (46 days). Black MBC patients experienced the shortest mean time to chemotherapy after surgery (39 days), whereas Asian MBC patients experienced the longest time to chemotherapy (50 days). In survivorship, Black and Asian patients were least likely to undergo screening mammography (33.3%, and 43.3%, respectively), compared to 52% of White and 50% of Hispanic MBC patients. Ultimately, 13% of Asian and 11% of Hispanic MBC patients died of breast cancer, compared to 6.7% of Black and 6.2% of White MBC patients. Conclusions: While we found no statistically significant differences in mortality by race among MBC patients, our findings indicate that non-white patients had longer time to treatments, less survivorship screening, and worse disease related mortality than their white counterparts. Future study can elucidate these racial inequalities, enabling more equitable breast cancer treatment among patient subgroups.