Mode of lymph node metastases in esophageal cancer induced in rabbits with Vx2 carcinoma.

We carried out experimental studies in which Vx2 carcinoma was inoculated submucosally into the esophagi of 57 rabbits. The purpose was to clarify the mode of tumor growth and lymph node metastasis of esophageal cancer. The inoculation was given into five different segments of the esophagus and the cardia in six different groups of rabbits: the cervical (Ce), the cervicothoracic junction (Ce=Iu), the upper thoracic (Iu), the middle and lower thoracic (ImEi) and the abdominal (Ea) segments and the cardia (C). The lymph node metastatic pattern of the Vx2 carcinoma was then observed. The Ce and Ce=Iu located carcinomas metastasized mainly above the tracheal bifurcation; the ImEi located carcinomas metastasized equally above and below the tracheal bifurcation. In cases of the Ea and C located carcinomas, the lymph node metastasis was restricted to the abdomen when serosal invasion was excluded but it spread widely from the abdomen to the neck when serosal invasion was positive. Thus, in experimentally-induced carcinoma, tracheal lymph node metastasis occurred with a high frequency. As intraoperative assessment is closely related to anatomical factors and operative risk, care should be taken that such assessments are thoroughly carried out.