A Randomized Controlled Trial to Improve Lymph Node Assessment in Stage II Colon Cancer

HYPOTHESIS Physicians seem to learn best from their peers, yet the impact of opinion leaders on physician behavior is unclear. Because colon cancer staging has been identified as being suboptimal in Ontario, Canada, we sought to evaluate the influence of expert and local opinion leaders for colon cancer on optimizing colon cancer lymph node assessment. DESIGN, SETTING, PARTICIPANTS A cluster-randomized trial including all hospitals in Ontario that identified a local opinion leader with intervention between January 5 and June 17, 2004. INTERVENTION All 42 centers received a standardized lecture about colon cancer lymph node assessment delivered by an expert opinion leader in colon cancer. The 21 intervention hospitals also received academic detailing of a local opinion leader by the expert opinion leader and a toolkit. MAIN OUTCOME MEASURES Mean number of lymph nodes assessed in patients with stage II colon cancer and the proportion of cases staged with a minimum of 12 lymph nodes before and after a standardized lecture were assessed. RESULTS Patient demographic and tumor factors were similar in both groups before and after the standardized lecture. Lymph node assessment significantly improved after the standardized lecture at intervention and control sites (P