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.