Racial disparities in prostate cancer incidence rates by census division in the United States, 1999-2008.

BACKGROUND

Black men have a higher incidence of prostate cancer than white men in the U.S., but little is known whether incidence or racial differences vary geographically. Understanding these differences may assist future studies on causes of prostate cancer. To address such, we leverage the unique resource of the National Program of Cancer Registries (NPCR) combined with Surveillance, Epidemiology and End Results (SEER).

METHODS

Prostate cancer counts and population denominators by race (black, white), age, calendar year, and U.S. census division, for the period 1999-2008, were extracted from NPCR and SEER. We calculated age-standardized incidence rates (ASR) and estimated annual percent changes (EAPC) by race and census division. We assessed black-to-white incidence rate ratios (BWIRR) by census division and by calendar period.

RESULTS

This analysis included 1,713,471 prostate cancer cases and 1,217 million person-years. Black ASRs ranged from 176 per 100,000 person-years in Mountain division to 259 in Middle Atlantic. BWIRRs ranged from 1.20 in Western divisions to 1.72 in Southeastern divisions. EAPCs indicated that prostate cancer incidence is not decreasing in East South Central, unlike all other divisions. White EAPCs displayed similar variations by census division, resulting in modest temporal changes in BWIRRs.

CONCLUSIONS

Within the U.S., there exists significant geographic variability in prostate cancer incidence rates. Although there are large geographic differences in BWIRRs, temporal trends are fairly stable. This may indicate that primary factors affecting prostate cancer incidence rates vary geographically but affect both black and white men to a similar degree.