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.