Investigating Black-White differences in prostate cancer prognosis: A systematic review and meta-analysis

The case-fatality rate following a diagnosis of prostate cancer is higher for Black men compared to White men. How this elevated rate arises is uncertain, with differences in disease biology, presentation, treatment and comorbidity having been suggested. A systematic search was conducted for articles that reported ethnic differences in overall-survival, prostate cancer specific survival (PSS) or biochemical recurrence. 48 articles met the inclusion criteria. Black men had worse overall survival (risk ratio 1.35, 95% CI 1.23-1.48) but this was not due to comorbidity alone as PSS and risk of biochemical recurrence were also elevated (1.29, 95% CI 1.13-1.47 and 1.34, 95% CI 1.23-1.46, respectively). Studies adjusting for clinical predictors and socioeconomic variables no longer supported a difference in overall survival (1.01, 95% CI 0.88-1.16), but continued to find an increased risk amongst Black men for PSS (1.13, 95% CI 1.00-1.27) and biochemical recurrence (1.25, 95% CI 1.11-1.41). Similar results were seen for studies from the pre-PSA era and free-health care settings. In contrast to others, studies of metastatic cancer did not find evidence of Black-White differences (p for interaction = 0.01). In conclusion, Black men had a poorer prognosis which was not fully explained by comorbidity, PSA screening, or access to free health care, although few studies measure these factors well. Either management differences for local disease and/or biological differences may be behind Black-White differences in prostate cancer prognosis.