Surgical volume influences survival in patients undergoing resections for stage II colon cancers

There is current interest in the correlation between surgical volume and outcomes. Survival in patients with rectal cancer appears to improve when carried out by surgeons who do high volumes of procedures. A similar correlation for patients with colon cancer has never been clearly established. The aim of this study was to determine whether surgical volume was an independent predictor for survival in patients undergoing surgery for stage II colon cancer. Population-based findings were collected from all patients diagnosed with stage II colon cancer in Western Australia between 1993 and 2003. The Kaplan-Meier product limit estimate of survival was used to calculate overall and cancer-specific survival. The Cox proportional hazards model was used to define the correlation between a number of covariates and survival. The results are recorded as hazard ratio (HR) with 95% confidence intervals (CI). From 1993 to 2003, 1467 patients underwent resections for stage II colon cancers. Significant independent predictors for overall survival were surgeon carrying out more than 25 procedures (P = 0.0001, HR 0.657, 95%CI 0.532-0.811), surgery in a private hospital (P = 0.0001, HR 0.487, 95%CI 0.400-0.594), use of chemotherapy (P = 0.001, HR 0.664, 95%CI 0.496-0.837), age at diagnosis (P = 0.0001, HR 1.014, 95%CI 1.027-1.044) and T staging and vascular invasion (T4 and vascular positive P = 0.001, HR 1.850, 95%CI 1.294-2.645). Surgical volume was a significant independent predictor for survival in patients undergoing resections for stage II colon cancers. Surgeons carrying out only 25 procedures over a 10-year period outperformed surgeons doing fewer cases.