Additional lymphadenectomy might not improve survival of patients with resectable metastatic colorectal adenocarcinoma of T4 stage, proximal location, poor/undifferentiation, or N3/N4 stages: a large population-based study

This study was performed to evaluate the prognostic effect of lymphadenectomy on outcomes in patients with resectable metastatic colorectal adenocarcinoma (mCRC). We selected patients with mCRC from 2004 to 2013 from Surveillance, Epidemiology, and End Results Program (SEER) database. Kaplan-Meier analysis, univariate Cox regression and multivariate Cox regression analysis were performed to assess the clinical value of lymphadenectomy on overall survival (OS) and cause-specific survival (CSS) of patients with resectable mCRC. A total 24178 eligible patients were included, 23056 (95.36%) of which received lymphadenectomy. Results showed that lymphadenectomy was an independent protective factor for survival of patients with mCRC overall [OS (HR: 0.86, 95%CI: 0.79-0.93, P=0.002) and CSS (HR: 0.85, 95%CI: 0.78-0.93, P