The number of lymph node metastases influences survival and International Union Against Cancer tumor-node-metastasis classification for esophageal squamous cell carcinoma: does lymph node yield matter?

摘要

In a recent paper in Diseases of the Esophagus, Zhang and colleagues conclude that "The number of lymph node metastases influences survival and International Union Against Cancer tumor-node-metastasis classification for esophageal squamous cell carcinoma." However, in their subgroup of patients, the average lymph node yield (LNY) is less than 4 (1146 patients with 4270 LNs harvested), and the number is too low to appropriately evaluate the International Union Against Cancer (UICC) tumor-node-metastasis classification for esophageal cancer. The current UICC classification demands for six LNs for pathologic lymph node (pN) staging.2 It is considered that the minimal regional LNY of six LNs as recommended by the UICC for esophageal carcinoma is far too low to appropriately stage the disease.3 Based on an international study including 3651 patients, Peyre et al.4 concluded that the number of LNs removed is an independent predictor of survival after esophagectomy for cancer, and to maximize this survival benefit, a minimum of 23 regional LNs must be removed. In Dr Rizk's analysis,5 a total of 4627 patients who had esophagectomy alone for esophageal cancer were identified from the Worldwide Esophageal Cancer Collaboration database.