Lymph Node Ratio Improves TNM and Astler-Coller's Assessment of Colorectal Cancer Prognosis: an Analysis of 761 Node Positive Cases

Prognosis assessment of node-positive colorectal cancer patients by Astler-Coller (AC) and TNM classifications is suboptimal. Recently, several versions of lymph node ratio (LNR; ratio metastatic/examined nodes) have been proposed but are still mostly unused. The prognostic value of several criteria, including LNR (two classes-LNR1 and LNR2-identified by a 15 % cut-off) was studied in 761 consecutive patients, from 2000 through 2010. The relationships between total examined nodes, N, T and LNR were also analysed. LNR1 and LNR2 patients' survival was analysed within AC and TNM subgroups, and then coupled with them. Age, tumour location and LNR are independent factors predicting survival. The relationships between LNR, N stage and T stage with examined nodes suggest confusing factors. LNR allows for identification of subgroups with different survival within AC and TNM classifications (p < 0.0001). Patients with LNR class discordant from AC stage (LNR1-C2 and LNR2-C1) have a similar 5-year survival (54 and 57 %, respectively). LNR2 and TNM stage IIIC define a poor 5-year prognosis (33 %). LNR is a powerful prognosis predictor, easily integrated with TNM and AC classifications to improve prognosis assessment and facilitate clinical use. Possible confusing factors should be considered in future studies.