Lymph node ratio versus TNM system as prognostic factor in colorectal cancer staging. A single Center experience

Objective: This study aims to establish the actual validity of the lymph node ratio (LNR) as a prognostic factor for colorectal cancer patients, and to verify differences of survival and disease-free interval. Methods: Patients referred with colorectal cancer who underwent potentially curative surgery between January 1997 and December 2011 were included. Lymph node ratio, TNM staging and survival were extracted from surgical, histological and follow-up records.Results: Two hundred eigthy six patients with different stages of colorectal cancer underwent surgery, with comparison of survival prediction based on lymph node ratio and TNM staging. The overall survival rate was 78.3%, the recurrence rate was 11.9% and the mortality rate was estimated as 21.7%. Univariate analysis in relation to survival was significant for the following variables: serum level of CEA, CA 19.9 value, degree of histological differentiation, and tumor growth. There weren't any statistically significant differences for the LNR (LNR = 0.16: p = 0.116). The TNM system was effective both in discriminating between survival stages (Stage II vs. Stage III: p = 0.05) and in differentiating sub-groups (p = 0.05).Conclusions: LNR alone could not be considered a better prognostic factor than the TNM system. However, future studies are needed in a larger number of patients with a standardized surgical, pathological and medical protocol.