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

Abstract

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 I-III 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 I-III colon cancer. All 8901 patients in Denmark diagnosed with adenocarcinoma of the colon and treated with curative resection in the period 2003-2008 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.