Black men with newly diagnosed nonmetastatic prostate cancer had no significant difference in prostate cancer–specific mortality compared with white men when treated with a standardized approach and follow-up or at a health care system with standardized access, according to recent research published in.
Robert T. Dess, MD, from the department of radiation oncology at the University of Michigan, Ann Arbor, and colleagues examined data from 296,273 patients in the Surveillance, Epidemiology, and End Results (SEER) cohort, 3,972 patients from the Veterans Affairs (VA) health system, and 5,854 patients in four randomized controlled trials (RCTs) from the National Cancer Institute–sponsored Radiation Therapy Oncology Group between January 1992 and December 2013. Of these, 52,840 patients (17.8%) in the SEER cohort, 1,513 patients (38.1%) in the VA cohort, and 1,129 (19.3%) in the RCT cohort were black men. The mean age across all cohorts was 64.9 years, and the median follow-up was 75 months in the SEER cohort, 97 months in the VA cohort, and 104 months in the RCT cohort.
After adjustment for age in the SEER cohort, black men had a 30% increased risk of prostate cancer–specific mortality (PCSM) compared with white men (subdistribution hazard ratio, 1.30; 95% CI, 1.23-1.37; P less than .001). However, after the researchers performed inverse probability weighting (IPW) to adjust for race-based imbalances such as access to care and standardized treatment, there was a 0.5% increased risk over 10 years (sHR, 1.09; 95% CI, 1.04-1.15; P less than .001) after diagnosis.
In the VA cohort, IPW yielded no significant differences between black men and white men (sHR, 0.85; 95% CI, 0.56-1.30; P = .46), and there was a significantly lower risk for black men in the RCT cohort after IPW (sHR, 0.81; 95% CI, 0.66-0.99; P = .04). With regard to other outcomes, other-cause mortality was significantly higher for black men in the SEER cohort (sHR, 1.30; 95% CI, 1.27-1.34; P less than .001) and in the RCT cohort (sHR, 1.17; 95% CI, 1.06-1.29; P = .002) after IPW.
“Black race remains associated with many factors that negatively affect outcomes, and disparities persist at the population level,” Dr. Dess and colleagues wrote in their study. “Continued efforts are needed to address this clear racial health inequity driven by modifiable nonbiological risk factors.”
The researchers said some residual confounding may exist, but noted the strengths of the study included a diverse cohort with a large range of treatment approaches.
This study was funded in part by the Prostate Cancer Foundation, a grant from the Prostate Cancer National Institutes of Health Specialized Programs of Research Excellence, two grants from the Department of Defense, a grant from NIH, and a grant from the NIH Cancer Center. One or more of the authors reported relationships in the form of grants, personal fees, and consulting fees with numerous companies. The other authors report no relevant conflicts of interest.
SOURCE: Dess RT et al. JAMA Oncol. 2019 May 23. doi: .