Prognostic Impact of Main Lymph Node Metastasis in Patients with Colon Cancer

Background: Although extended lymph node dissection during colon cancer surgery is recommended in both Western and Eastern countries, the perception and clinical significance of main lymph node metastasis (MLNM) remains controversial. Methods: In total, 1557 patients with colon cancer who underwent curative resection with D3 dissection were retrospectively analyzed. Clinicopathological factors associated with MLNM were analyzed. Kaplan–Meier survival analysis and log-rank tests were used to compare the prognosis between the MLNM and non-MLNM groups. Results: Multivariate analysis showed that overall survival (OS) [hazard ratio, 2.117 (0.939–4.774), p = 0.071] and recurrence-free survival (RFS) [hazard ratio, 2.183 (1.182–4.031), p = 0.013] were affected by the MLNM status independent of the TNM stage. Survival analysis demonstrated that among patients with stage III disease, the OS and RFS rates were significantly different between patients with and without MLNM (OS: p = 0.0147, RFS: p = 0.0001). However, the OS and RFS rates were not significantly different between patients who had stage III disease with MLNM and patients who had stage IV disease (OS: p = 0.5901, RFS: p = 0.9610). Conclusions: MLNM is an independent prognostic factor for patients with colon cancer. The addition of the MLNM status to the current TNM classification may enhance the prognostic value of the TNM staging system and the clinical efficacy of adjuvant therapy in patients with colon cancer.