Impact of the number of resected lymph nodes on postoperative survival of patients with node-negative oesophageal squamous cell carcinoma

Abstract

Research on the number of resected lymph nodes (LNs) in the cases of node-negative oesophageal squamous cell carcinoma (ESCC) is inadequate. This study was designed to analyse the prognostic impact of the number of resected LNs on node-negative ESCC. Node-negative ESCC patients (n = 666) who underwent oesophagectomy between January 1990 and December 2005 were classified into three groups according to the number of LNs resected during surgery (≤8, 9-15 and ≥16). Kaplan-Meier curves and stratified analyses according to the American Joint Committee on Cancer staging were used to compare oesophageal cancer-specific survival (CSS). Cox regression and stratified analyses were used to identify the independent prognostic factors related to postoperative survival. CSS rates increased with the number of negative resected LNs (P < 0.01). Three- and 5-year survival rates were 67.8 and 59.8%, respectively, for patients with ≥16 resected LNs, 64.8 and 53.8%, respectively, for patients with 9-15 resected LNs and 55.3 and 43.6%, respectively, for patients with ≤8 resected LNs. Multivariate analysis showed that the number of resected nodes [P < 0.01, relative risk (RR) = 1.0, 95% confidence interval (CI) 1.0-1.0] was an independent factor for CSS among node-negative ESCC patients. Further stratified analysis revealed that the number of resected LNs was an independent factor for survival in Stage IIA ESCC patients (P < 0.01, RR = 0.9, 95% CI 0.9-1.0). The number of resected LNs is an independent prognostic factor for the survival of node-negative ESCC patients. The minimum resection number recommended for accurate staging is 16.