[Clinical analysis of the characteristics of thoracic lymph node metastasis in lung cancer: A report of 318 cases].

BACKGROUND: To investigate the clinical characteristics of thoracic lymph node metastasis in lung cancer. METHODS: Three hundred and eighteen patients with lung cancer underwent pneumonectomy or lobectomy and lymphadenectomy from Jan 2000 to Jan 2002. RESULTS: A total of 1534 groups of lymph nodes were removed. Metastatic frequency of thoracic lymph nodes was 58.5% (186/318), in which N1 was 27.0% (86/318), N2 was 31.4% (100/318). There were higher frequencies of lymph node metastasis in 4, 7, 10, 11 regions around the root of lung. Among the skipping N2 metastasis (14.5%, 46/318), upper lobe cancer led to only upper mediastinal lymph node metastasis, however, lower or right middle lobe cancer caused both upper and lower mediastinal lymph node metastasis. Of the patients with swelling hilar and mediastinal lymph nodes reported by preoperative CT scan, only 48.2% were confirmed with lymph node metastasis by postoperative histopathology; while 22.4% of the patients with normal size lymph nodes had lymph node metastasis. CONCLUSIONS: If there is no hilar and inferior carinal metastatic lymph node in patients with upper lobe cancer, the lower mediastinal lymph node dissection might not be necessary. But systematic mediastinal lymph node dissection should be performed in patients with lower lobe or right middle lobe cancer whether there is hilar or inferior carinal metastatic lymph node or not. The extent of lymph node dissection should not depend on the results of preoperative chest CT scan.