The relation between lymph node status and survival in Stage I-III colon cancer: results from a prospective nationwide cohort study

Aim This study involved a large nationwide Danish cohort to evaluate the hypothesis that a high lymph node harvest has a positive effect on survival in curative resected Stage IIII colon cancer and a low lymph node ratio has a positive effect on survival in Stage III colon cancer. Method Analysis of overall survival was conducted using a nationwide Danish cohort of patients treated with curative resection of Stage IIII colon cancer. All 8901 patients in Denmark diagnosed with adenocarcinoma of the colon and treated with curative resection in the period 20032008 were identified from the Danish Colorectal Cancer Group (DCCG). The impact of lymph node count and lymph node ratio was analysed. Results Overall 5-year survival was 56.8 and 66.6%, (P<0.0001) for lymph node counts of fewer than 12 and 12 or more, respectively. The percentages of lymph node positive patients in the two groups were 29.8 and 40.3% (P<0.0001), respectively. When putting the Stage III patients into four subgroups according to the lymph node ratio (cut-off points 1/12, 1/4 and 1/2) we found an overall 5-year survival rate of 68.1, 57.2, 49.3 and 32.4% (P<0.0001). Lymph node count and lymph node ratio were independent prognostic factors in multivariate analysis. Conclusion High lymph node count was associated with improved overall survival in colon cancer. Lymph node ratio was superior to N-stage in differentiating overall survival in Stage III colon cancer. Stage migration was observed.