Background: The purpose of this prospective study was to examine the influence of hospital caseload on long-term outcome following standardization of rectal cancer surgery at a national level.
Methods: Data relating to all 3388 Norwegian patients with rectal cancer treated for cure between November 1993 and December 1999 were recorded in a national database. Treating hospitals were divided into four groups according to their annual caseload: hospitals in group 1 (n = 4) carried out 30 or more procedures, those in group 2 (n = 6) performed 20-29 procedures, group 3 (n = 16) 10-19 procedures and group 4 (n = 28) fewer than ten procedures.
Results: The 5-year local recurrence rates were 9.2, 14.7, 12.5 and 17.5 per cent (P = 0.003) and 5-year overall survival rates were 64.4, 64.0, 60.8 and 57.8 per cent (P = 0.105) respectively in the four hospital caseload groups. An annual hospital caseload of less than ten procedures increased the risk of local recurrence compared with that in hospitals where 30 or more procedures were performed each year (hazard ratio 1.9 (95 per cent confidence interval (c.i.) 1.3 to 2.7); P < 0.001). Overall survival was lower for patients treated at hospitals with an annual caseload of less than ten versus hospitals with 30 or more (hazard ratio 1.2 (95 per cent c.i. 1.0 to 1.5); P = 0.023).
Conclusion: The rate of local recurrence was higher for hospitals with a low annual caseload of less than ten procedures than for hospitals with a high treatment volume of 30 or more. Patients treated in small hospitals also had a shorter long-term survival than those treated in large hospitals.