Upfront surgery for clinical N1 stage II non-small cell lung cancer.

PURPOSE: To identify the high-risk subgroup of outcomes following upfront surgery for clinical (c)-N1 stage II non-small cell lung cancer (NSCLC). METHODS: Between 2009 and 2022, 140 patients underwent upfront lung resection of more than one lobe with mediastinal lymphadenectomy for cN1 stage II NSCLC. The subjects of this retrospective study were 129 of these patients, whose cN1 node was confirmed pathologically as metastasis after surgery. “Continuous cN1” was an N1 node directly involving the primary tumor. Disease-free survival (DFS) and overall survival (OS) were estimated using log-rank tests. RESULTS: Continuous cN1 was detected in 55 patients (43%). Lobectomy, bilobectomy, and pneumonectomy were performed in 95 (74%), 20 (16%), and 14 (11%) patients, respectively. Bronchoplasty and vascular plasty were performed in 43 patients (33%) and 25 patients (19%), respectively. The pathological nodal status was pN1 only in 92 patients (71%) and pN2 with pN1 in 37 patients (29%). Multivariate analysis identified that a solid component size > 40 mm was an independent predictor of poor DFS (p = 0.020) and OS (p = 0.001). CONCLUSIONS: A solid component size of > 40 mm was a poor prognostic factor for the DFS and OS of patients with cN1 stage II NSCLC, suggesting that induction therapy should be considered for this subgroup.