Socioeconomic status, race, and long-term outcomes after radical prostatectomy in an equal access health system: Results from the SEARCH database.

INTRODUCTION: We previously found racial differences in biochemical recurrence (BCR) after radical prostatectomy (RP) persisted after adjusting for socioeconomic status (SES) while SES did not predict BCR. The impact on long-term prostate cancer (PC) outcomes is unclear. We hypothesized higher SES would associate with better long-term outcomes regardless of race.

METHODS: Among 4,787 black and white men undergoing RP from 1988 to 2015 in the SEARCH Database, poverty (primary SES measure) was estimated by linking home ZIP-code to census data. Cox models were used to test the association between SES adjusting for demographic, clinicopathological features, and race with BCR, castration-resistant PC (CRPC), metastases, PC-specific mortality (PCSM), and all-cause mortality. Interactions between race and SES were tested.

RESULTS: Median follow-up was 98 months (Interquartile range: 54-150 months). There were no interactions between race and SES for BCR. Black men had 10%- to 11% increased BCR risk (P < 0.06) while SES was unrelated to BCR. There were interactions between SES and race for CRPC (P = 0.002), metastasis (P = 0.014), and PCSM (P = 0.004). Lower SES was associated with decreased CRPC (P = 0.012), metastases (P = 0.004), and PCSM (P = 0.049) in black, but not white men (all P ≥ 0.22). Higher SES was associated with decreased all-cause mortality in both races.

CONCLUSIONS: In an equal-access setting, lower SES associated with decreased CRPC, metastases, and PCSM in black but not white men. If confirmed, these findings suggest a complex relationship between race, SES, and PC with further research needed to understand why low SES in black men decreased the risk for poor PC outcomes after RP.