Assessing the relative influence of hospital and surgeon volume on short-term mortality after radical cystectomy

Objectives: To assess the relationship between surgeon (SV) and hospital volume (HV) on mortality after radical cystectomy (RC). Patients and Methods: We queried the National Cancer Database (NCDB) for adult patients undergoing RC between 2010 and 2013. We calculated average volume for each surgeon and hospital. Using propensity-scored weights for combined volume groups with a proportional hazards regression model, we compared the associations between HV and SV with 90-day survival after RC. Results: A total of 19 346 RCs were performed at 927 hospitals by 2 927 surgeons in the period 2010–2013. The median (interquartile range) HV and SV were 12.3 (5.0–35.5) and 4.3 (1.3–12.3) cases, respectively. For HV, 90-day unadjusted mortality was 8.5% in centres with <5 cases/year (95% confidence interval [CI] 7.7–9.3) and 5.6% in those with >30 cases/year (95% CI 5.0–6.2). For SV, 90-day mortality was 8.1% for surgeons with <5 cases/year (95% CI 7.6–8.6) and 4.0% for those with >30 cases/year (95% CI 2.8–5.2; all P < 0.05). The 30-day mortality rate was lowest for the combined HV–SV groups with HV >30, ranging from 1.6% to 2.1%. Conclusions: In hospitals reporting to the NCDB, volume was associated with improved mortality after RC. These associations appear to be driven by hospital- rather than surgeon-level effects. An elevated SV had a beneficial effect on mortality at the highest-volume hospitals. These findings inform efforts to regionalize complex surgical care and improve quality at community and safety net hospitals.