Factors determining survival in resected N2 lung cancer.

This retrospective study was based on 237 patients with non-small cell lung cancer (NSCLC) and nodal N2 disease. All accessible mediastinal lymph nodes (LN) were removed and classified according to their anatomical location in LN chains. The pulmonary resections performed were: pneumonectomy (n = 187), lobectomy (n = 44) and segmentectomy (n = 4). There was solitary nodal chain involvement by metastasis in 141 cases, two chains in 72 cases and three or more in 24; "skip" metastases were present in 26.6%. N2 disease would have been missed in 45 cases of single chain involvement (31.9%) if routine removal of mediastinal nodes had not been performed. The overall 5-year survival rate was 18.8%. Survival was not influenced by site, size or extension (T) of tumor, tumor histology or the presence of vascular invasion. The prognosis was significantly worsened by the presence of microscopic residual disease (30 cases) and of satellite nodules (23 cases). Survival was significantly improved when metastases involved a single LN chain (26.3 versus 8.3%, P = 0.0003). The location and number of involved nodes in the chain, "skip" metastases and the presence of extracapsular spread of carcinoma did not influence the prognosis. Routine mediastinal LN dissection is necessary to improve survival and for classification of lung cancer. Anatomic description allows better understanding of N2 disease which is not a contraindication to surgery when a gross complete resection can be achieved.