Prognostic Impact of Distribution of Lymph Node Metastases in Stage III Colon Cancer

Complete mesocolic excision (CME) with central vascular ligation (CVL) is a well-known concept in colon cancer surgery. However, data on the oncological benefits of CVL are scarce. The objective of this study was to evaluate the prognostic significance of the distribution of lymph node metastases (LND) in patients with stage III colon cancer who underwent CME with CVL. In total, 446 consecutive patients who underwent curative resection for stage III colon cancer from 2005 to 2011 were analyzed. Patients were classified as having LND1 (metastases in pericolic nodes), LND2 (metastases in intermediate nodes), or LND3 (metastases in main nodes). Survival outcomes were compared among the three groups. LND1, LND2, and LND3 were identified in 299 (67.0 %), 122 (27.4 %), and 25 (5.6 %) patients, respectively. The 5-year overall survival and relapse-free survival (RFS) of all patients were 86.7 and 76.2 %, respectively. The 5-year RFS of patients with LND1, LND2, and LND3 were 82.8, 65.4, and 52.0 %, respectively (p < 0.0001). Multivariate analysis showed that LND2 was an independent prognostic factor for RFS (p = 0.0185), although the significance of LND3 was marginal (p = 0.0621). Among patients with pN1, the 5-year RFS of patients with LND1 and LND2+3 were significantly different (84.4 vs. 71.5 %, respectively, p = 0.0102), and similar tendency was found between patients with pN2-LND1 and pN2-LND2+3 (72.6 vs. 53.1 %, p = 0.0428). The high 5-year survival rates of patients with stage III colon cancer, even those with LND2 and LND3, would justify CVL as the standard procedure for advanced colon cancer.