[Evaluation of hilar and mediastinal lymph node metastases in resected cases of bronchogenic carcinoma].

To establish a reasonable regional lymph node dissection as curative operation for lung cancer, hilar and mediastinal lymph node metastases were analyzed. From 1982 to December, 1990, 404 patients underwent pulmonary resection with complete mediastinal node dissection. There were 194 adenocarcinomas, 175 squamous cell carcinomas, 14 large cell carcinomas, 13 small cell carcinomas and 8 others. The rates of hilar (N1) and mediastinal lymph node (N2) metastasis were 12.4% and 28.9% in adenocarcinoma, 12.6% and 30.3% in squamous cell carcinoma, 14.2% and 28.6% in large cell carcinoma and 15.4% and 30.8% in small cell carcinoma. In cases with adenocarcinoma, there was a close relationship between mediastinal metastasis and grade. No lymph node metastasis was seen in cases with tumor less than one cm in diameter. However, mediastinal node metastasis was found in cases with one cm or more in diameter of primary lesion and rates of metastasis were increased in proportion to tumor size. Because considerable metastases are found in the mediastinal lymph nodes and exact diagnosis of node metastasis before and during operation is difficult, complete mediastinal node dissection is still standard as curative resection for resectable lung cancer except lesion less than one cm in diameter or early hilar type squamous cell carcinoma.