Effect of visceral obesity on Lymph node metastasis in colon cancer

Abstract

Background and Aims Obesity is an established risk factor for colorectal cancer (CRC). However, the relationship between visceral obesity and CRC outcome including lymph node metastasis has not been well studied. The goal of this study was to determine the impact of visceral obesity on lymph node metastasis and overall survival (OS) in CRC. Methods This study reviewed medical records for 379 consecutive patients who underwent radical resection for CRC between 2003 and 2008. Metastatic lymph node ratio (MLR) was defined as the number of involved nodes by tumor divided by the total number of resected lymph nodes. Visceral (VFA) and subcutaneous fat areas (SFA) were determined by measuring abdominal fat volume distribution via CT scan, and visceral obesity was defined as a VFA to total fat area ratio [V/T] > 0.29. Results Two hundred and seventy-eight patients were divided into two groups: VFs (V/T ≤ 29%) and VFv (V/T > 29%). Thirty-five of 81 patients (43.2%) in the VFs group and 47 of 197 patients (23.9%) in the VFv group had an MLR ≥ 18% (P = 0.001). In a multivariate analysis, there were positive associations between MLR and undifferentiated histologic grade, lympho-vascular invasion, and peri-neural invasion, and an inverse association between MLR and V/T (OR = 0.413, 95% CI = 0.216 – 0.789, P = 0.007). Furthermore, patients with visceral obesity tended to have significantly better OS than patients with non-visceral obesity. Conclusion Higher V/T ratio, a measure of visceral obesity, was significantly associated with decreased MLR and better OS for CRC.