Demographic differences in prostate cancer incidence and stage: An examination of population diversity in California

Introduction: Geographic and racial/ethnic variability in prostate cancer incidence rates and stage distribution ma;ri be partly attributed to differences in screening and ear ly detection. Methods: Using California Cancer Registry data we aimed to characterize variability in prostate cancer rates statewide and to examine differences in the stage at diagnosis of prostate cancer by racial/ethnic group statewide and by census tract per capita income in San Diego County. We calculated annual average (1988-1991) age-adjusted incidence rates per 100,000 (AAIR) of prostate cancer for 49,880 men over age 34 years. Racial/ethnic groups were compared using incidence rate ratios (IRR) (AAIR localized plus regional stages AAIR distant stage). Results: Statewide, Caucasians showed a higher IRR [6.16, 95% confidence interval (CI), 6.00-6.30] than did African Americans (2.34, 95% CI, 1.89-2.89), Hispanics (3.84, 95% CI; 3,63-4.05), or Asian/others (3.61, 95% CI, 1.80-7.22). Within San Diego County, Caucasians living in higher per capita income census tracts (greater than or equal to 65th percentile) had a significantly higher IRR (8.80, 95% CI 7.84-9.89) than did lower-income tracts (5.68, 95% CI, 5.13-6.30). Conclusion: Findings from the present and similar studies suggest that outcomes research is needed to determine the impact of these demographic differences on prostate cancer mortality and quality of life. This is particularly important given the current controversy regarding the treatment of clinically localized prostate cancers, increasingly found through early detection, which often involve difficult choices between aggressive therapies including prostatectomy or watchful waiting.