Spatial patterns of localized-stage prostate cancer incidence among white and black men in the southeastern United States, 1999-2001.

BACKGROUND: In the United States, prostate cancer incidence is higher among black than among white males, with a higher proportion of blacks diagnosed with advanced-stage cancer.
METHODS: Prostate cancer incidence (1999-2001) and census tract data were obtained for 66,468 cases in four states that account for 20% of U.S. blacks: Georgia, Florida, Alabama, and Tennessee. Spatial clusters of localized-stage prostate cancer incidence were detected by spatial scan. Clusters were examined by relative risk, population density, and socioeconomic and racial attributes.
RESULTS: Overall prostate cancer incidence rates were higher in black than in white men, and a lower proportion of black cases were diagnosed with localized-stage cancer. Strong associations were seen between urban residence and high relative risk of localized-stage cancer. The highest relative risks generally occurred in clusters with a lower percent black population than the national average. Conversely, of eight nonurban clusters with significantly elevated relative risk of localized-disease, seven had a higher proportion of blacks than the national average. Furthermore, positive correlations between percent black population and relative risk of localized-stage cancer were seen in Alabama and Georgia.
CONCLUSION: Association between urban residence and high relative risk of localized-stage disease (favorable prognosis) persisted after spatial clusters were stratified by percent black population. Unexpectedly, seven of eight nonurban clusters with high relative risk of localized-stage disease had a higher percentage of blacks than the U.S. population. IMPACT: Although evidence of racial disparity in prostate cancer was found, there were some encouraging findings. Studies of community-level factors that might contribute to these findings are recommended. Copyright 2010 AACR.