Lymph node ratio as determined by the 7th edition of the American Joint Committee on Cancer staging system predicts survival in stage III colon cancer.

ABSTRACT

BACKGROUND AND OBJECTIVES: The aim of this study was to evaluate the prognostic usefulness of the lymph node ratio (LNR) in stage III colon cancer using the 7th edition of the American Joint Committee on Cancer (AJCC) staging system. METHOD: We analyzed data from 130 consecutive patients with stage III colon cancer. Kaplan-Meier and Cox proportional hazard model analyses were used to evaluate prognostic effects. RESULTS: Quartile analysis indicated that an LNR of 0.1638 was the best cut-off value with regard to predicting disease-free survival (DFS). Six patients had stage IIIA disease, 102 patients had stage IIIB disease, and 22 patients had stage IIIC disease. For patients with stage IIIB disease, the 3-year DFS for an LNR of <0.1638 (N = 87) and an LNR of ≥0.1638 (N = 15) was 79.0% and 50.0%, respectively (P = 0.015). For patients with stage IIIC disease, the 3-year DFS for an LNR of <0.1638 (N = 6) and an LNR of ≥0.1638 (N = 16) was 100% and 28.6%, respectively (P = 0.03). CONCLUSIONS: The authors found that 7th AJCC stage IIIB and stage IIIC patients are heterogeneous groups with respect to DFS, when stratified by LNR, and suggest that an LNR-based algorithm be devised for incorporation into the 7th AJCC staging system.