Association of African-American ethnic background with survival in men with metastatic prostate cancer

Background: African-American men have earlier onset of prostate cancer, hig her prostate-specific antigen (PSA) levels, more advanced stage at diagnosi s, and higher mortality than white men. It is not known whether the poorer survival of African-American men with prostate cancer reflects their later stage at diagnosis or differences in the basic biology of their disease. To evaluate this question, we examined outcomes of African-American and white men with metastatic prostate cancer in the context of a randomized clinica l trial. Methods: Southwest Oncology Group Study 8894 was a randomized phas e III trial that compared orchiectomy with or without flutamide in men with metastatic prostate cancer. Using data from 288 African-American and 975 w hite men in the trial, we conducted a proportional hazards regression analy sis to determine if ethnicity was an independent predictor of survival. All statistical tests were two-sided. Results: African-American men were more likely than white men to have extensive disease and bone pain and had poore r performance status, younger age at study entry, higher Gleason score, and higher PSA levels, After adjustment for these prognostic variables, the ha zard ratio (HR) for all-cause mortality for African-American men relative t o white men was 1.23 (P = .018), Further adjustment for initial quality-of- life assessments also resulted in higher HRs associated with African-Americ an ethnicity relative to white ethnicity (HR = 1.39; P = .007), Conclusions : African-American men with metastatic prostate cancer have a statistically significantly worse prognosis than white men that cannot be explained by t he prognostic variables explored in this study. These data should give incr eased impetus for efforts to detect the disease early in African-American m en and for the development of more effective therapies based on potential b iologic differences in this ethnic group.