Prognostic Value of Examined and Metastatic Lymph Nodes in Chinese Esophageal Squamous Cell Carcinoma Patients Received Lymphadenectomy

Data were collected on a large multi-institution dataset consisting of ESCC patients who underwent surgery between January 2003 and December 2013 at ten institutions in the People's Republic of China. The datasets were approved for research by the institutional review board of each participating center. Prior to surgery, all patients received computerised tomography (CT) of the chest and abdomen and EUS as part of their routine staging workup. Patients received whole body FDG-PET to eliminate the possibility of distant metastases if the attending physician considered it was necessary. All patients in the dataset received a surgical R0 resection; patients who received an R1 or R2 resection were excluded. Notably, there is nothing approaching a consensus on the extent of lymph node dissection for ESCC patients. Patients who received neoadjuvant therapy were excluded due to the influence of neoadjuvant therapy on lymph node status and pathologic T stage. The primary endpoints were overall survival (OS), which was defined as the time between surgical resection and death from any cause, and cancer-specific survival (CSS), defined as the time from surgical resection to death caused by ESCC. After receiving esophagectomy, patients were followed up by clinical examination every three months for the first year, every three to six months for the second year, and every six to twelve months from then on.