Perioperative outcomes and lymph node assessment after induction therapy in patients with clinical N1 or N2 non-small cell lung cancer

Background: Induction therapy has been shown to benefit patients with resectable stage-2 or stage-3 nonsmall cell lung cancer (NSCLC). We aimed to determine if induction chemotherapy (CTx) with or without radiation therapy (+/- RT) for NSCLC with clinical lymph node (LN) involvement (cN1 or cN2) affects LN dissection or perioperative outcomes during robotic-assisted video thoracoscopic (RAVTS) lobectomy. Methods: We retrospectively analyzed patients who underwent RAVTS lobectomy for NSCLC over 45 months. We assessed clinical LN status by CT scan, PET scan, endobronchial ultrasound, and/or mediastinoscopy. We grouped patients with cN1 or cN2 as: "no induction therapy", "induction CTx alone" (ICTx), or "induction CTx + RT" (ICTx + RT). Intraoperative estimated blood loss (EBL), operative times, tumor size, LN status, and restaging were noted. Results: Of 256 NSCLC patients who had lobectomy, there were 52 cN1 or cN2 patients, of whom 39 patients had "no induction", 7 had ICTx, and 6 had ICTx + RT. Higher rates of recurrent laryngeal nerve (RLN) injury, tracheal/bronchial injury, and pulmonary embolism were observed with ICTx +/- RT (P=0.02, 0.04, and 0.02, respectively). Total number of complications was not significantly different, nor were perioperative outcomes, such as EBL, operative time, and in-hospital mortality. Fewer N2 LN stations were assessed after ICTx +/- RT (3.7 +/- 0.2 vs. 4.2 +/- 0.2 stations; P=0.04), but total number of LNs reported were not significantly different (13.0 +/- 2.3 vs. 16.2 +/- 1.0 LNs, P=0.22). Of "no induction" patients, 15.4% were upstaged pathologically; no patients were upstaged after induction therapy. While 30.8% of ICTx +/- RT patients were downstaged, 38.5% of "no induction" patients were also downstaged on final pathology. Conclusions: Induction CTx +/- RT for cN1 or cN2 NSCLC patients did not affect EBL, operative times, or in-house mortality after RAVTS lobectomy. Patients undergoing RAVTS lobectomy after ICTx+ RT may be at greater risk for RLN injury, tracheal/bronchial injury, and pulmonary embolism. Fewer N2 LN stations, but not numbers of LNs, are assessed after ICTx +/- RT. Induction therapy does not lead to increased downstaging.