Lymph node metastatic patterns and the development of multidisciplinary treatment for esophageal cancer.

Abundant lymphatic flow and the anatomical location of the esophagus can result in the widespread distribution of lymph node metastasis of esophageal cancer from the cervical to the abdominal field. Historically, the Japan Esophageal Society and American Joint Committee on Cancer offer two different classifications of lymph node group location surrounding the esophagus. The location of sentinel lymph nodes in midthoracic esophageal cancer reflects the variety of lymphatic drainage routes. In fact, in cT1N0 esophageal cancer, pathological lymph node metastasis has been observed from the cervical to the abdominal field, and the locations were shown to be closely linked to the primary tumor location in advanced stages. While the impact of histology on the distribution of LN metastasis has been extensively debated, a recent prospective study on esophagogastric junction cancer found that metastatic patterns did not differ by histology. Thoracic duct lymph nodes were defined as one of the regional lymph node stations in the mediastinum. Although lymph node metastasis around the thoracic duct has occasionally been observed, the oncologic impact of thoracic duct lymph node dissection has not been fully elucidated. To eradicate tumors locoregionally, three-field lymph node dissection, a strategy for extended lymph node clearance, has been established. In esophagectomy, three-field lymph node dissection is defined as a procedure for complete regional cervico-thoraco-abdominal lymph node dissection. However, its therapeutic efficacy must be evaluated based on the balance between oncological outcomes and possible added surgical risk. To further improve survival, multidisciplinary treatment consisting of surgery, chemotherapy, and radiotherapy has been established worldwide as a standard treatment for esophageal cancer. Now that neoadjuvant therapy followed by esophagectomy is the standard, adding adjuvant therapy including immunotherapy could be a promising treatment option. The ideal combination of various multidisciplinary treatment approaches and extensive LN dissection need to be established to improve the oncological outcomes for EC patients.