Status of Involved Lymph Nodes and Direction of Metastatic Lymphatic Flow Between Submucosal and T2-4 Thoracic Squamous Cell Esophageal Cancers

Background Three-field lymph node dissection for thoracic esophageal cancer is associated with high morbidity and reduced quality of life after surgery. Consequently, minimized lymphadenectomy would be desirable, if appropriate. In the present study, we retrospectively analyzed the status of involved nodes and the direction of metastatic lymphatic flow from tumors into involved nodes to determine whether submucosal squamous cell esophageal cancers are potential candidates for minimized lymphadenectomy. Methods We enrolled 199 patients who received esophagectomy with extensive lymph node dissection between 1989 and 2005 and retrospectively analyzed their prognoses, distribution of solitary metastatic lymph nodes, and the direction of metastatic lymphatic flow from the tumor, taking into consideration tumor location and depth. Results Of these patients with submucosal cancers, 83% had 1 or 2 involved nodes, and their esophageal cancer-specific 5-year survival rate was 66%. Solitary lymph node metastasis did not occur in neck lymph nodes in lower thoracic submucosal esophageal cancers, and the direction of metastatic lymphatic flow from the tumor was almost always in one direction. By contrast, T2–4 cancers with 2–4 involved nodes had bidirectional metastatic lymphatic flow from the tumor. Conclusions There was a difference in the status of lymph node metastasis and the direction of metastatic lymphatic flow from tumors into involved nodes between submucosal and T2–4 thoracic squamous cell esophageal cancers. This analysis may be useful for developing an approach to minimized lymphadenectomy for thoracic esophageal cancers.