Black men in trials for prostate cancer have greater baseline disease severity but achieve better treatment outcomes than white men
Black men enrolled in clinical trials for prostate cancer appear to have more aggressive disease upon entry yet have better clinical outcomes than their white male counterparts. This was the conclusion of a meta-analysis by a team from Department of Radiation Oncology, University of California, US.
Data from the US suggests that African Americans have the highest death rate and shortest survival of any racial or ethnic group for most cancers. In fact, it has been estimated that 1 in 6 black men will be diagnosed with prostate cancer in their lifetime compared with 1 in 8 white men. The reasons for this disparity remain uncertain although in one study which examined the impact of several factors including access to care and demographics, survival was significantly worse for Black men after adjusting for demographics and comorbidities. Moreover, a further analysis revealed how Black men with intermediate to high risk prostate cancer, were less likely to be treated with curative intent than white men. But when access to care is comparable, research suggests that black men with non-metastatic prostate cancer appeared to have similar stage-for-stage prostate cancer–specific mortality to white men. Although prostate cancer specific mortality (PCSM) is clearly the most important outcome, no studies have examined the impact of race and the early metrics associated with a response to treatment such as biochemical recurrence (BCR) and the development of distant metastasis (DM).
For the present analysis, the US team sought to elucidate whether there were any associations between race and both early and late outcomes in men with localised prostate cancer. They performed a systematic review and meta-analysis of randomised trials which had enrolled a large number of black men. Included studies compared radiotherapy with or without short or long-term androgen deprivation therapy. The primary outcomes of interest were BCR, DM and PCSM and regression analysis with adjustment for several factors, was used to estimate the hazard ratios (HRs) for BCR, DM, PCSM and all-cause mortality (ACM).
Findings
Overall, seven trials were identified and included in the analysis. These trials has a total of 8814 patients with an overall mean age of 69.1 years, of whom, 18.5% (1630) were black men and the median follow-up time was 10.6 years.
The median age of black men was significantly younger (68 vs 71, p < 0.001) than white men although they were also significantly more likely to present with high-risk disease (38.2% vs 30.4%, p < 0.001) with higher prostate specific antigen levels (10.3 vs 8.4, p < 0.001) and Gleason scores of 8 to 10 (16.3% vs 14.1%, p = 0.03).
However, in regression analysis, black race was associated with a lower risk of BCR (HR = 0.88, 95% CI 0.80 – 0.96, p = 0.006), DM (HR = 0.72, 95% CI 0.58 – 0.91, p = 0.005) and PCSM (HR = 0.72, 95% CI 0.54 – 0.97, p = 0.03). Despite these potential racial advantages, there was no significant difference in time to ACM (HR = 0.99, 95% CI 0.92 – 1.07, p = 0.87). There were also no important differences with respect to the type of treatment used.
The authors concluded that while black men appeared to enter trials with high-risk disease features, they had better outcomes than their white counterparts and that black race may be an independent and favourable prognostic variable.
Citation
Ma TM et al. Comparison of Response to Definitive Radiotherapy for Localized Prostate Cancer in Black and White Men: A Meta-analysis JAMA Netw Open 2021
