Black-white differences in survival from late-stage prostate cancer

To examine differences between African Americans (Blacks) and non-Hispanic Whites in risk of death after diagnosis of later-stage prostate cancer in a large sample of patients from US population-based cancer registries. The theory that Black patients with advanced cancer have a lower survival rate compared to their White counterparts, based on a single clinical trial, was tested with large samples of patients.

The Cox proportional hazards regression model was used to compare survival rates among 24,136 non-Hispanic White, and 3,817 Black prostate cancer patients diagnosed between 1988 and 1997, whose cancer had spread beyond the prostate capsule, and who resided in 9 geographic areas covered by the National Cancer Institute's Surveillance, Epidemiology and End Results (SEER) Program of population-based cancer registries. Other analyses involved 5- and 10-year relative survival rates (RSRs) among non-Hispanic White and Black patients diagnosed with distant-stage prostate cancer from 1973 to 1994 (with almost all patients having had a chance to survive for at least 5 years).

The risk of death from prostate cancer was only slightly higher for Blacks than for Whites (adjusted hazard rate ratio = 1.05), when age, extent of disease, tumor grade, marital status, and surgery were included in the Cox proportional hazards regression model. Five- and 10-year RSRs were about 2%-22% higher for Blacks and Whites in strata defined by extent of disease, or among patients with distant stage cancer, but differences were small among married patients.

The findings do not indicate substantial Black-White differences in survival rates of later-stage prostate cancer patients, after adjusting for clinical characteristics and marital status.