Lymph node counts, rates of positive lymph nodes, and patient survival for colon cancer surgery in Ontario, Canada: A population‐based study

BACKGROUND AND OBJECTIVES: This study assessed lymph node counts, lymph node status (positive or negative), and survival among patients undergoing colon cancer surgery in Ontario, Canada. METHODS: We obtained data from the Ontario Cancer Registry on 960 patients who underwent a major colon cancer resection in years 1991-1993. Patients and hospitals were ranked by lymph node count to correlate lymph node counts and lymph node status. For node-negative patients we assessed the influence of patient, hospital, and tumor factors on lymph node counts and survival. RESULTS: The rate of node-positive patients was similar among the lymph node count groups. For example, the odds ratio of a patient being node positive if the lymph node count was 10-36 versus 1-3 was 1.0 (CI 0.6-1.6, P = 0.42). Among node-negative patients, survival was improved for patients with a high (10-36) versus low (1-3) lymph node count (HR 0.6, CI 0.4-1.0, P = 0.03). No patient, hospital, or tumor factors predicted both a higher lymph node count and improved survival. CONCLUSIONS: In this population-based study of patients undergoing colon cancer surgery, higher lymph node counts did not correlate with increased rates of node-positive status.