African-American men and prostate cancer-specific mortality: a competing risk analysis of a large institutional cohort, 1989-2015

Abstract

Significant racial disparities in prostate cancer (PCa) outcomes have been reported, with African-American men (AAM) more likely to endure adverse oncologic outcomes. Despite efforts to dissipate racial disparities in PCa, a survival gap persists and it remains unclear to what extent this disparity can be explained by known clinicodemographic factors. In this study, we leveraged our large institutional database, spanning over 25 years, to investigate whether AAM continued to experience poor PCa outcomes and factors that may contribute to racial disparities in PCa. A total of 7307 patients diagnosed with PCa from 1989 through 2015 were included. Associations of race and clinicodemographic characteristics were analyzed using chi-square for categorical and Mann-Whitney U-test for continuous variables. Racial differences in prostate cancer outcomes were analyzed using competing risk analysis methods of Fine and Gray. Median follow-up time was 106 months. There were 2304 deaths recorded, of which 432 resulted from PCa. AAM were more likely to be diagnosed at an earlier age (median 60 vs. 65 years, P = <0.001) and were more likely to have ≥1 comorbidities (13.6% vs. 7.5%, P < 0.001). In a multivariate competing risk model, adjusted for baseline covariates, AAM experienced significantly higher risk of PCSM compared to NHW men (HR, 1.62, 95% CI, 1.02-2.57, P = 0.03) NHW. Among men diagnosed at an older age (>60 years), racial differences in PCSM were more pronounced, with AAM experiencing higher rates of PCSM (HR, 2.05, 95% CI, 1.26-3.34, P = 0.003). After adjustment of clinicodemographic and potential risk factors, AAM continue to experience an increased risk of mortality from PCa, especially older AAM. Furthermore, AAM are more likely to be diagnosed at an early age and more likely to have higher comorbidity indices.

Keywords: African-American men; competing risk analysis; disparity; other cause mortality; prostate cancer; prostate cancer-specific mortality.

Figure 1

Consort diagram for the inclusion and exclusion criteria. *In consort diagram indicated the other race that were excluded in the analysis.

Figure 2

Kaplan–Meier curve for prostate cancer‐specific mortality within the strata of race.

Figure 3

Kaplan–Meier curve for racial difference in prostate cancer‐specific mortality among men with age at diagnosis >60 years.

Figure 4

Kaplan–Meier curve for racial difference in prostate cancer‐specific mortality among men with age at diagnosis ≤60 years.