Objective.-To evaluate long-term survival of black and white prostate cancer patients in an equal-access medical care system to help distinguish biological from medical and social explanations of mortality differences. Design and Setting.-Retrospective study of US Department of Defense tumor registry patients with prostate cancer. Ethnicity, age, diagnosis, staging, risk factors, treatment, and survival end points were extracted. Patients.- Prostate cancer patients (N=1606; 7.5% black, 92.5% white) who were active- duty personnel, dependents, or retirees eligible for care in the military medical system. Main Outcome Measures.-Racial differences in tumor stage and grade, risk factors, recurrence, and treatment wait time (time between initial diagnosis and initial treatment); influence of stage, grade, treatment, wait time, age, and race on survival. Results.-No differences were found in behavioral risk factors or tumor grade or size, but blacks entered active treatment (P<.001) and exhibited a higher relative risk of cancer (P=.01) in younger age groups, presented with higher stage (P<.001), and demonstrated increased progression in distant metastatic disease (P=.01). No significant differences were detected in overall wait time. When adjusted for stage, no difference was found in type of treatment. Overall, stage, grade, and age were found to affect survival (P=.04 to P<.001), but race did not. When analyzed by stage, blacks demonstrated a clear trend of longer survival for distant metastatic disease (P=.04 to P=.06). This trend was confirmed using Kaplan-Meier estimates (P=.04, likelihood ratio). Conclusions.-This analysis suggests that in an equal-access medical care system there are no stage-specific differences in treatment between black and white prostate cancer patients. Survival among blacks is similar to that among whites and may surpass it for high-stage disease.
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