Proposal for reasonable mediastinal lymphadenectomy in bronchogenic carcinomas: Role of subcarinal nodes in selective dissection

Objective: The aims of this study were to reveal the characteristics of ski pping N2 lung cancer and to develop a more reasonable approach for dissecti ng mediastinal lymph nodes. Methods: Of consecutive 956 patients who were o perated on for primary lung cancer from 1986 through 1996, 760 (79.5 %) had a diagnosis of non-small cell carcinoma and were subjected to complete res ection of the tumor together with hilar and mediastinal lymphadenectomy. Re sults: Of 141 patients with N2 disease, 53 (37.6%) had skipping metastases, Among 78 patients with N2 cancer of the upper lobe, 37 (47.4%) had skippin g metastases affecting upper or aortic mediastinal nodes whereas none of th em had skipping metastases affecting lower mediastinal nodes. Among 47 pati ents with N2 cancer of the lower lobe, 13 (27.7%) had skipping metastases a ffecting mediastinal bodes. Of these 13 patients, 11 (84.6%) had skipping m etastases affecting the subcarinal node. The remaining 2 patients had a hug e primary tumor. Conclusions: Dissection of the upper part of the mediastin um including the aortic regions should be performed regardless of the opera tive appearance when cancer is located in the upper lobe, but it is not req uired for lower lobe tumors with negative hilar and subcarinal nodes. Disse ction of the subcarinal node in patients with an upper lobe tumor is not ro utinely needed when the nodes in both the hilum and upper mediastinum are i ntact. We consider that the subcarinal node is of significance and skipping metastases should be defined as metastases that skip the subcarinal node i n addition to N1 nodes.