Extent of mediastinal node metastasis in clinical stage I non-small-cell lung cancer: The role of systematic nodal dissection

Objective: To determine the extent of lymph node metastasis in clinical stage I non-small-cell lung cancer (NSCLC). Methods: We performed a retrospective review of 524 patients with clinical stage I NSCLC who underwent lobectomy with systematic nodal dissection. Results: The nodal status was NO in 409 patients (78%), N1 in 44 (8%), N2 in 67 (13%), and N3 in four (0.8%). Thirty-six patients had single-level mediastinal nodal metastases and 35 had multi-level metastases. The incidence of N2/3 disease in patients with adenocarcinoma/squamous cell carcinoma/other histologic types according to tumor size was 0/0/0%, respectively, in tumors less than or equal to 10 mm in diameter, 12/0/0% in tumors 11-20 mm in diameter, 14/4/23% in tumors 21-30 mm in diameter, and 26/14/20% in tumors > 30 mm in diameter. Nodal metastases to the upper mediastinum from middle or lower lobe lesions were frequently observed in 51 N2 adenocarcinomas, whereas those to the lower mediastinum from upper lobe lesions were rare. Of 10 N2 squamous cell carcinomas, seven had regional and three had non-regional nodal metastases. The 5-year survival rate was 68, 43, and 30% in N0, N1, and N2: respectively (P < 0.01, N0 versus N1, N0 and N2). Conclusions: Systematic mediastinal nodal dissection should be routinely performed for clinical stage I lung cancer to ensure the correct nodal status, but it might be dispensable in the patients with peripheral squamous cell carcinoma 120 mm in diameter, with central squamous cell carcinoma less than or equal to 30 mm, and with adenocarcinoma less than or equal to 10 mm. When systematic nodal dissection cannot be performed, the incidence and extent of nodal metastases should be taken account with respect to histologic type, size, and location of the tumor. (C) 1998 Elsevier Science Ireland Ltd. All rights reserved.