Extent of Lymph Node Dissection in Patients with Small-Sized Peripheral Non-Small Cell Lung Cancer during Intentional Segmentectomy

PURPOSE: Segmentectomy and mediastinal lymph node dissection (MLND) are becoming standard procedures for small-sized (<2 cm) peripheral non-small cell lung cancer (NSCLC). Although the benefits of the less resected lung are proven, the extent of lymph node dissection remains unchanged. METHODS: We studied 422 patients who underwent lobectomy with MLND (lobe specific or systemic) for small peripheral NSCLC with clinical N0 disease. Patients with middle lobectomy (n = 39) and a consolidation-to-tumor (C/T) ratio ≤0.50 (n = 33) were excluded. We investigated the clinical factors, lymph node metastasis distributions, and lymph node recurrence patterns of 350 patients. RESULTS: Thirty-five (10.0%) patients had lymph node metastasis; none with C/T ratio <0.75 had lymph node metastasis and lymph node recurrence. None had solitary lymph node metastasis in the outside lobe-specific MLND. Six patients had mediastinal lymph node metastasis at the initial site of recurrence; none had mediastinal lymph node recurrence outside the lobe-specific MLND, except for two patients with S6 primary disease. CONCLUSION: NSCLC patients with small peripheral tumors and a C/T ratio <0.75 during segmentectomy may not require MLND. The optimal MLND for patients with a C/T ratio ≥0.75, except for those with S6 primary, may be lobe-specific MLND.