Factors contributing to the racial differences in prostate cancer mortality

OBJECTIVE To analyse, in a retrospective cohort study, differences in rates of surgical treatment for prostate cancer between African-Americans and White Americans, and to evaluate the extent to which these differences are associated with disparities in survival rates between these groups. PATIENTS AND METHODS Clinical, pathological, and demographic data from 4279 men diagnosed with clinically localized prostate cancer between 1980 and 1997 were used. The variables assessed included age, disease stage, tumour grade, comorbidities, treatment method, and socio-economic status (SES). Kaplan-Meier survival curves were generated and compared using log-rank tests. The Cox proportional hazards method was used for analyses involving adjustments for potential confounding factors. RESULTS The surgical treatment rate was 17% for African-American and 28% for White patients (P < 0.001). In those patients treated conservatively or by radiation therapy, both crude and cancer-specific survival rates were lower for African-Americans than for Whites (P < 0.001). However, for patients undergoing surgery, differences in survival between African-Americans and Whites were not statistically significant. According to our models, SES explained 50% and surgical treatment rates approximate to 34% of the differences in survival between African-Americans and Whites. CONCLUSIONS This analysis suggests that the lower prostate cancer survival rates for the African-Americans in the present population can be largely explained by differences in SES and lower surgical treatment rates. Efforts to increase awareness of treatment options among African-American patients may be a way of improving survival in this group.