Experimental study of lymph node metastasis in thoracic esophageal carcinoma--regarding lymph node metastasis and changes in lymphatic flow by ultrafine charcoal in rabbit esophageal carcinoma model]

Esophageal carcinoma models were created by transplanting VX2 cells to rabbit esophagus endoscopically. By injecting finely divided activated charcoal into normal rabbit esophagus and tumor sites of esophageal carcinoma model, lymph flow was observed directly. Existence of lymph node metastasis was studied in detailed pathology. In 30 rabbits with upper esophageal carcinoma, lymph node metastasis was seen in 77%. Metastasis to bilateral intrathoracic paratracheal lymph node was seen in 50%, and also concentration of lymphatic flows from tumor site was seen. However, there were no metastasis and no lymph flow to abdominal lymph nodes. While, metastasis to cervical lymph nodes showed around 13%. Esophageal lymphatic flows were also seen reaching the cervical area along the esophagus. In 40 models with mid lower esophageal carcinoma, lymph node metastasis were seen in 88%. Metastasis to right and left thoracic paratracheal lymph nodes was 75% and 53%, respectively, and 25% of metastasis went to cardia lymph nodes. The lymph flows were going up and down around these lymph nodes, and reaching to lymph nodes at upper highest mediastinum or left gastric artery. The metastatic rate to the cervical lymph nodes was about 5%. There were no significant differences in lymphatic metastasis between right and left mediastinum. These findings suggest the necessity of radical dissection for both sides of the mediastinum.