Effect of centralization on complex surgical care: A population-based case study of radical cystectomy

Introduction: We sought to determine whether non-mandated or passive centralization of radical cystectomy (RC) to higher-volume centers leads to enhanced processes of care and outcomes. Methods: This is a population-based, retrospective, cohort study that used the Ontario Cancer Registry (OCR) to identify all incident patients who underwent RC from 1994-2013. Electronic records of treatment were linked to OCR; pathology records were obtained for all cases and reviewed by a team of trained data abstractors. The primary objective was to describe annual provider RC volumes. Secondary objectives included investigating process and outcome measures. Results: For the 5574 patients identified, the mean annual surgeon volume and hospital volume of RC from 1994 2008 was 4.5 (95% confidence interval [CI] 4.4-4.7) and 12.2 (95% CI 11.8-12.5), respectively. From 2009-2013, these volumes significantly increased to 6.8 (95% CI 6.5-7. 1) and 16.4 (95% CI 15.8-16.9). Process variables improved over time, including the use of neoadjuvant chemotherapy. Over the study period, there was a substantial improvement in cancer-specific survival (CSS): hazard ratio (HR) 0.60 (95% CI 0.53-0.67) for 2009-2013. During the most recent era, there was still evidence of a provider volume effect on both process measures and CSS. Conclusions: There has been recent passive centralization of RC to higher-volume providers in the province of Ontario, with measurable improvements in processes of quality care. Although centralization was also associated with improvement in CSS, in the most recent era, there continues to be low-volume providers with a residual volume-outcome effect.