Overall Survival of Black vs White Men Receiving Docetaxel Regimens for Metastatic Castration-Resistant Prostate Cancer
In an analysis reported in the Journal of Clinical Oncology, Halabi et al found that overall survival was improved for black men vs white men receiving regimens containing docetaxel and prednisone for metastatic castration-resistant prostate cancer. As noted by the investigators, several studies have indicated a shorter overall survival for black vs white men with localized prostate cancer.
Study Details
The analysis included individual patient data from 8,820 men with metastatic castration-resistant prostate cancer randomly assigned in 9 phase III trials to docetaxel/prednisone or a docetaxel/prednisone-containing regimen. The primary endpoint was overall survival.
Cox proportional hazards regression analysis was performed to assess the prognostic importance of black vs white race, with adjustment for risk factors common across the trials (ie, age, prostate-specific antigen [PSA], performance status, alkaline phosphatase, hemoglobin, and sites of metastases). Of the 8,820 men, 7,528 (85%) were white, 500 (6%) were black, 424 (5%) were Asian, and 368 (4%) were of unknown race.
Black men were younger and had worse performance status, higher testosterone and PSA levels, and lower hemoglobin levels vs white men (all P < .05). Median follow-up for surviving patients was 31 months.
Overall Survival
Despite differences in risk factors, median overall survival was 21.0 months for black men vs 21.2 months for white men. On multivariate analysis of pooled data from the 9 trials, black men were at significantly lower risk for death (hazard ratio = 0.81, P < .001). Hazard ratios favored black men in 6 of the 9 trials included in the analysis.
Among 4,172 men who were randomly assigned to docetaxel/prednisone alone, median overall survival was 22 months for black men vs 21 months for white men, with a pooled multivariate hazard ratio of 0.79 (95% confidence interval = 0.67–0.93).
The investigators concluded, “When adjusted for known prognostic factors, we observed a statistically significant increased [overall survival] in black vs white men with metastatic castration-resistant prostate cancer who were enrolled in these clinical trials. The mechanism for these differences is not known.”
Susan Halabi, PhD, of Duke University Medical Center, is the corresponding author for the Journal of Clinical Oncology article.
Disclosure: The study was supported by a United States Army Medical Research grant. The study authors’ full disclosures can be found at jco.ascopubs.org.
The content in this post has not been reviewed by the American Society of Clinical Oncology, Inc. (ASCO®) and does not necessarily reflect the ideas and opinions of ASCO®.
