[Regional lymph node staging and establishment of prognostic model for stage III( colon cancer]

To evaluate the clinical value of different regional lymph node staging system and to establish a predictive prognostic model for stage III( colon cancer.

A total of 256 Patients with stage III( colon cancer from January 1999 to December 2008 were identified from the China Medical University Cancer and underwent radical surgery. Based on information on regional lymph nodes, lymph nodes were staged LNR staging using pN stage in the 7th edition of the AJCC, the jN stage of the JGR, and LNR-stage on the basis of Log-rank statistics, respectively. Using the linear trend chi-square test, likelihood ratio Chi-square test, concordant index(c-index) to evaluate the homogeneity, monotonicity, and discrimination power of the staging system. Univariate and multivariate analyses were used to determine the clinical and pathological prognostic impact factors. After relevant diagnostic models were established, the Akaike Information Criterion (AIC) value was calculated to compare and identify the best diagnostic model.

Log-rank statistics found that 0.11 and 0.39 were the optimal cut-off point. LNR staging system included LNR1 (LNR<0.11), LNR2 (0.11,0.39), and LNR3(0.39,1). The concordance indices were 0.624 for pN, 0.611 for jN, and 0.700 for LNR. The heterogeneity was the lowest for LNR. Cox regression model was used to establish prognostic models for pN, jN, and LNR, and the AIC was 99.937, 71.631, and 65.548, respectively. The prognostic value was the highest for LNR.

LNR staging is the ideal staging system for stage III( colon cancer patients, which is better than the latest version of the current AJCC pN stage and JGR jN staging.