The effect of hospital and surgeon volume on racial differences in recurrence-free survival after radical prostatectomy.
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OBJECTIVE: This study investigates associations between hospital and surgeon volume, and racial differences in recurrence after surgery for prostate cancer. METHODS: Data from the 1991 to 2002 Surveillance, Epidemiology, and End-Results-Medicare database were examined for 962 black and 7387 white men who received surgery for prostate cancer within 6 months of diagnosis during 1993-1999. Cox regression models were used to estimate the relationships between volume (grouped in tertiles), recurrence or death, and race, controlling for age, Gleason grade, and comorbidity score. RESULTS: Prostate cancer recurrence-free survival rates improved with hospital and surgical volume. Black men were more likely to experience recurrence than white men [hazard ratio (HR) = 1.34; 95% confidence interval (CI): 1.20-1.50]. Stratification by hospital volume revealed that racial differences persisted for medium and high volume hospitals, even after covariate adjustments (medium HR = 1.30, 95% CI: 1.04-1.61; high HR = 1.36, 95% CI: 1.07-1.73). Racial differences persisted within medium and high levels of surgeon volume as well (medium HR = 1.43, 95% CI: 1.10-1.85; high HR = 1.57, 95% CI: 1.14-2.16). CONCLUSIONS: High hospital and physician volumes were not associated with reduced racial differences in recurrence-free survival after prostate cancer surgery, contrary to expectation. This study suggests that social and behavioral characteristics, and some aspects of access, may play a larger role than organizational or systemic characteristics with regard to recurrence-free survival for this population.