An increased number of negative lymph nodes is associated with a higher immune response and longer survival in colon cancer patients.

BACKGROUND: The purpose of the present study was to examine the relationship among the number of negative lymph nodes (LNs), the local and systemic immune response, and survival in patients with colon cancer. PATIENTS AND METHODS: One thousand one hundred and fifty-seven patients with colon cancer who underwent surgery at Sun Yat-sen University Cancer Center between 2009 and 2014 were included. We examined negative LNs in relation to the local and systemic immune response, including percentage carcinoma, neutrophil and lymphocyte infiltration, Crohn's-like reaction, neutrophil to lymphocyte ratio, platelets, and C-reactive protein (CRP). Disease-free survival and overall survival were also examined. We performed subgroup analysis based on the distribution of negative LNs. RESULTS: An increased number of negative LNs was associated with greater neutrophil invasion (p=0.001), more lymphocyte invasion (p=0.001), and more Crohn's-like reaction (p=0.001). No significant correlation was observed between negative LNs and the neutrophil to lymphocyte ratio. More than 12 negative LNs were associated with increased platelets and CRP levels. A higher number of negative LNs was independently associated with longer disease-free survival in stage I+II patients (p=0.004) and stage III patients (p=0.015), while negative LNs were also independent prognostic factors in stage IV patients (p=0.007). CONCLUSION: Our study suggests that negative LNs are indicators of the immune response and are associated with a better prognosis in patients with colon cancer.