Disease-free survival difference between African Americans and whites after radical prostatectomy for local prostate cancer: a multivariable analysis.

OBJECTIVES: Age-adjusted mortality rates (per 100,000) for men with prostate cancer from 1991 through 1997 reported by the Surveillance, Epidemiology, and End Results national registry have consistently demonstrated that African-American men (AAM) have twice the death rate of white men (WM). However, there has been considerable controversy as to how this relates to progression-free survival among these men. In an attempt to address this controversy of localized prostate cancer, we report on a multivariable analysis of survival data of a large number of AAM and WM who underwent radical prostatectomy.
METHODS: The study cohort was composed of 791 men whose only prostate cancer treatment was radical prostatectomy performed between July 1990 and December 1999. The variables analyzed were age, preoperative prostate-specific antigen level, pathologic grade and stage, and race/ethnicity. Pathologic examination of all specimens was performed in a uniform manner according to an established protocol. Multivariable analysis based on Cox's proportional hazards regression model was performed to assess whether a significant difference in progression-free survival time between AAM and WM persisted after controlling for the main effects of other prognostic factors.
RESULTS: The study cohort consisted of 229 AAM and 562 WM. Our results indicated that all variables, except age, had highly significant effects on progression-free survival, even in the presence of other predictors.
CONCLUSIONS: The effects of age, preoperative serum prostate-specific antigen level, and pathologic grade and stage did not account for the racial disparity in progression-free survival among men diagnosed with clinically localized prostate cancer and treated with radical prostatectomy.