Number of lymph nodes examined and prognosis of TNM stage II colorectal cancer

Abstract

Purpose : The diagnosis of lymph-node-negative colorectal cancer should imply a good prognosis, but the outcome for TNM stage II patients remains spotty. We determined whether the number of lymph nodes found affects this prognosis. Materials and Methods : Data on TNM stage II or III patients who underwent surgery for colorectal cancer between 1981 and 2000 was taken from a database and surgery compared using Kaplan-Meier curves and the log-rank test. Multivariate analysis was conducted using a Cox regression model. Results : We analyzed 229 TNM stage II cases and, for comparison, 204 stage III cases. Lymph node retrieval in stage II cases was affected by patient age (P = 0.0035), emergency operation (P = 0.0010), and tumor site (P = 0.0030). In stage III cases, lymph node retrieval was affected by gender (P = 0.0108) and invasion depth (P = 0.0085). Decreased lymph node detection was associated with an increased hazard ratio among 229 TNM stage II patients. Five-year survival for patients with stage III tumors with only 1-3 positive lymph nodes (61.6%) was similar to that of patients with stage II tumors who had 11 or fewer lymph nodes (68.5%). Conclusions : The prognosis of TNM stage II colorectal cancer depends on the number of lymph nodes found and, presumably those with stage II tumors and only a few nodes found routinely be provided postoperative chemotherapy. ©2006 The Japanese Society of Gastroenterological Surgery.