Background — Hospital and surgeon (provider) volume are associated with clinically significant outcomes for many types of surgery. Volume-outcome studies in patients undergoing radical cystectomy for bladder cancer have focused primarily on postoperative mortality. In the current study, the authors assessed the effect of cystectomy provider volume on long-term mortality.
Methods — Using administrative databases, 2535 patients who underwent cystectomy by 199 surgeons in 90 hospitals in Ontario, Canada, between 1992 and 2004 were identified. The impact of provider volume on overall survival (OS) was assessed using Cox proportional hazards models fully adjusted for patient and tumor characteristics. Separate models were fit to examine the effect of surgeon and hospital volume. To confirm that the impact of volume on OS was independent of the effect of volume on short-term mortality, analyses were repeated excluding those patients experiencing postoperative deaths.
Results — Of 2535 patients, 1796 (70.9%) died during the study period. Both higher hospital volume (hazards ratio [per unit increase in average annual number of procedures], 0.995; 95% confidence interval, 0.990-1.000 [P5.044]) and higher surgeon volume (hazards ratio, 0.984; 95% confidence interval, 0.975-0.994 [P5.002]) were found to be significantly associated with improved OS. Excluding post-operative deaths did not alter the results. Further analyses revealed that the benefit of high volume was attained by receiving care from either high-volume hospitals or high-volume surgeons.
Conclusions — High-volume providers were associated with improved long-term mortality rates compared with low-volume providers. This finding was independent of the effect of volume on perioperative mortality, suggesting that provider volume effects continue to manifest long after surgery.
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