Volume-outcome analysis of colorectal cancer-related outcomes

Background: Significant associations between caseload and surgical outcomes highlight the conflict between local cancer care and the need for centralization. This study examined the effect of hospital volume on short-term outcomes and survival, adjusting for the effect of surgeon caseload. Methods: Between 1998 and 2002, 8219 patients with colorectal cancer were identified in a regional population-based audit. Outcomes were assessed using univariable and multivariable analysis to allow case mix adjustment. Surgeons were categorized as low (26 or fewer operations annually), medium (27-40) or high (more than 40) volume. Hospitals were categorized as low (86 or fewer), medium (87-109) or high (more than 109) volume. Results: Some 7411 (90.2 per cent) of 8219 patients underwent surgery with an anastomotic leak rate of 2.9 per cent (162 of 5581), perioperative mortality rate of 8.0 per cent (591 of 7411) and 5-year survival rate of 46.8 per cent. Medium- and high-volume surgeons were associated with significantly better operative mortality (odds ratio (OR) 0·74, P = 0.010 and OR 0.66, P = 0.002 respectively) and survival (hazard ratio (HR) 0.88, P = 0.003 and HR 0.93, P = 0.090 respectively) than low-volume surgeons. Rectal cancer survival was significantly better in high-volume versus low-volume hospitals (HR 0.85, P = 0.036), with no difference between medium- and low-volume hospitals (HR 0·96, P = 0·505). Conclusion: This study has confirmed the relevance of minimum volume standards for individual surgeons. Organization of services in high-volume units may improve survival in patients with rectal cancer.