Black men with prostate cancer have historically been found to have worse outcomes compared to other racial/ethnic groups. This finding has primarily been attributed to differences in genetics, health care access, and socioeconomic status. We sought to validate this relationship between race and prostate cancer specific mortality (PCSM) in a large national cohort of American veterans. We used a nationwide database of the Veterans Health Administration (VHA) by means of the VA Informatics and Computing Infrastructure (VINCI). Our initial query captured 82,886 patients who were diagnosed with prostate cancer from 2000 to 2015 and had received radiation therapy as part of their initial treatment. To control for possible confounders, patients who received brachytherapy, surgery, or had metastatic disease at diagnosis were excluded. Covariates included age at diagnosis, T stage, Gleason score, PSA at diagnosis, administration of ADT, Charlson Comorbidity Index (CCI) score, tobacco/alcohol history, marital status, employment status, and median income. Patients who lacked data for covariates were excluded. We compared baseline characteristics between blacks and other racial/ethnic groups with Pearson’s chi-squared and Mann-Whitney U tests. We compared PCSM and non-prostate cancer mortality (NPCM) between groups using multivariable Cox proportional hazards models. Our final study cohort included 27,753 patients, of which 8,453 (30.5%) were black. At time of diagnosis, blacks were younger (64 vs 67, p<0.001), had a higher PSA (12.6 vs 10.2, p<0.001), and were more likely to have a CCI score of 2+ (24.5% vs 19.8%, p<0.001). Additionally, they were more likely to have T1 disease (72.6% vs 62.3%, p<0.0001) and slightly more likely to receive ADT (47.5% vs 46.1%, p=0.037). Blacks were less likely to have Gleason 8+ disease (20.6% vs 22.5%, p<0.001). Controlling for potential confounders, we found improved PCSM among blacks (HR 0.86, 95% CI 0.77 to 0.97, p=0.012). Increasing age, PSA, T stage, Gleason score, and CCI score were associated with worse PCSM. In addition to improved PCSM, we also found that black patients had improved NPCM compared to other racial/ethnic groups (HR 0.812, 95% CI 0.76 to 0.87, p<0.0001). Our discovery of improved prostate cancer specific mortality and non-prostate cancer mortality among black veterans demonstrates a unique racial disparity paradox that has not been seen in the general population. Further research is required to determine if our results are driven by systematic differences in the cohort or in VHA care delivery.
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