Evidence of the effect of 'specialization' on the management, surgical outcome and survival from colorectal cancer in Wessex

Background: A prospective audit of the management of colorectal cancer was established to investigate factors associated with variation in survival observed within the former Wessex region (population three million). Methods: Some 5173 patients (4562 surgically treated) with colorectal cancer diagnosed between 1991 and 1994 were followed for 5 years. Details of referral, diagnosis, surgical treatment, postoperative complications and outcomes were collected. The association between surgical outcomes and survival and both case volume and specialization (defined to include membership of the Association of Coloproctology of Great Britain and Ireland) was explored, accounting for variables with prognostic significance. Results: There was a statistically significant association between high-volume operators (more than 50 operations per year) and specialization. The greatest benefit was observed with respect to specialists versus non-specialists, in terms of a lower postoperative mortality rate (odds ratio 0.67 (95 per cent confidence interval (c.i. 0.53 to 0.84))), lower anastomotic leak rates (odds ratio 0.46 (c.i. 0.31 to 0.66)), higher local recurrence-free survival (hazard ratio 0.56 (0.44 to 0.71)) and better long-term survival (hazard ratio 0.76 (c.i. 0.71 to 0.83)). Conclusion: There is a stronger association between surgical specialization in coloproctology and beneficial outcome than with high-volume caseloads. This is not entirely accounted for by case-mix or patient population, and is seen following colonic and rectal surgery and among patients with advanced disease.