The significance of lymph node status as a prognostic factor for esophageal cancer

The revision of the TNM Classification of Malignant Tumors, 7th Edition, suggests the lymph node (LN) status to be the most significant risk factor in esophageal cancer. This article reviews the current status of LNs as indicators of prognosis. The significance of the number of metastatic LNs, the number of resected LNs, and a novel index, the "LN ratio" (metastatic LNs/removed LNs) in patients with esophageal cancer, were reviewed. The number of metastatic LNs independently predicted the prognosis of both overall survival and relapse-free survival. The number of positive LNs was also the best predictive marker of survival. Furthermore, overall survival significantly depended on the number of surgically removed LNs, and the LN ratio closely correlated with survival. The LN status is considered to be the most significant information that can be used to predict the prognosis. However, there are many issues that still need to be resolved. Better knowledge of the N-status is therefore needed to effectively utilize this information. Further research should focus on the N-status of patients with esophageal cancer.