Workload and surgeon's specialty for outcome after colorectal cancer surgery

A large body of research has focused on investigating the effects of healthcare provider volume and specialization on patient outcomes including outcomes of colorectal cancer surgery. However there is conflicting evidence about the role of such healthcare provider characteristics in the management of colorectal cancer. To examine the available literature for the effects of hospital volume, surgeon caseload and specialization on the outcomes of colorectal, colon and rectal cancer surgery. We searched Cochrane Central Register of Controlled Trials (CENTRAL), and LILACS using free text search words (as well as MESH-terms). We also searched Medline (January 1990-September 2011), Embase (January 1990-September 2011) and registers of clinical trials, abstracts of scientific meetings, reference lists of included studies and contacted experts in the field. Non-randomised and observational studies that compared outcomes for colorectal cancer, colon cancer and rectal cancer surgery (overall 5-year survival, five year disease specific survival, operative mortality, 5-year local recurrence rate, anastomotic leak rate, permanent stoma rate and abdominoperineal excision of the rectum rate) between high volume/specialist hospitals and surgeons and low volume/specialist hospitals and surgeons. Two review authors independently abstracted data and assessed risk of bias in included studies. Results were pooled using the random effects model in unadjusted and case-mix adjusted meta-analyses. Overall five year survival was significantly improved for patients with colorectal cancer treated in high-volume hospitals (HR=0.90, 95% CI 0.85 to 0.96), by high-volume surgeons (HR=0.88, 95% CI 0.83 to 0.93) and colorectal specialists (HR=0.81, 95% CI 0.71 to 0.94). Operative mortality was significantly better for high-volume surgeons (OR=0.77, 95% CI 0.66 to 0.91) and specialists (OR=0.74, 95% CI 0.60 to 0.91), but there was no significant association with higher hospital caseload (OR=0.93, 95% CI 0.84 to 1.04) when only case-mix adjusted studies were included. There were differences in the effects of caseload depending on the level of case-mix adjustment and also whether the studies originated in the US or in other countries. For rectal cancer, there was a significant association between high-volume hospitals and improved 5-year survival (HR=0.85, 95% CI 0.77 to 0.93), but not with operative mortality (OR=0.97, 95% CI 0.70 to 1.33); surgeon caseload had no significant association with