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Extent of mediastinal lymph node dissection for clinical T1 non-small cell lung cancer.

The present study was designed to determine the extent of lymph node dissection for clinical T1 non-small cell lung cancer without negatively influencing curability. The study included 192 cases with clinical T1 non-small cell lung cancers who underwent lobectomy with mediastinal lymphadenectomy. Among 69 cases with right upper lobe tumors, metastasis was found in subcarinal lymph node in one case only. No metastasis was found in subcarinal node in cases free of metastasis in hilar and/or superior mediastinal nodes. Among 33 cases with right lower lobe tumors, metastasis was detected in the superior mediastinal node only in cases with metastasis in hilar and/or subcarinal nodes. Among 51 cases with left upper lobe tumors, no metastasis was found in the subcarinal node. Among 22 cases with left lower lobe tumors, metastasis was found in the superior mediastinal nodes only in cases with metastasis in hilar and/or subcarinal nodes. We propose the following scheme for the extent of mediastinal node dissection. Dissection of mediastinal node for clinical T1 non-small cell lung cancer cannot be omitted. But, 1) for upper lobe tumors, subcarinal lymphadenectomy could be omitted if no metastasis is found in hilar and superior mediastinal nodes based on gross and microscopic examination of frozen sections. 2) Similarly, for lower lobe tumors, superior mediastinal lymphadenectomy could be omitted if no metastasis is detected in the hilar and subcarinal nodes.