Mediastinal lymph node metastasis in patients with clinical stage I peripheral non-small-cell lung cancer.

Our aim in this study was to determine the mediastinal areas where lymphadenectomy should be done at the time of surgical resection of clinical stage I lung cancer. Between 1984 and 1994, 575 patients with clinical stage I non-small-cell lung cancer underwent lobectomy and systematic mediastinal lymphadenectomy. Mediastinal lymph nodes were pathologically positive for disease in 79 patients (14%), and positive nodes appeared normal intraoperatively in 54 patients (68%). Thirty-three percent of those patients with positive N2 (mediastinal) nodes had negative lobar (N1) nodes. In cancer of the right upper lobe, all N2 cases had the lymph node metastases in the superior mediastinal compartment. In cancer of the right middle lobe, all N2 cases but one had the metastases in subcarinal or anterior mediastinal nodes. In cancer of the right lower lobe, all N2 cases but one the metastases in subcarinal nodes. In cancer of the left upper lobe, all N2 cases had the lymph node metastases in the subaortic compartment. In cancer of the left lower lobe, all N2 cases but one had the lymph node metastases in the subcarinal area or subaortic compartment. In conclusion, systematic staging of mediastinal lymph nodes is necessary for all patients with resectable clinical stage I lung cancer. The location of the primary tumor determines the mediastinal areas where lymphadenectomy should be done to examine all lymph nodes.