Oncological outcomes after lobe-specific mediastinal lymph node dissection via multiport video-assisted thoracoscopic surgery

OBJECTIVES: We retrospectively investigated oncological outcomes after video-assisted thoracoscopic surgery (VATS) lobectomy with lobe-specific mediastinal lymph node dissection (MLND). METHODS: Between April 2008 and December 2016, a total of 660 patients underwent VATS lobectomy with lobe-specific MLND for clinical T1-3N0M0 non-small-cell lung cancer, of which 54 (8.2%) patients had pathological node-positive disease (18 N1 and 36 N2). We evaluated their oncological outcomes. RESULTS: The predominant histological type was adenocarcinoma (87%). Six (33%) patients in the pN1 and 11 (31%) patients in the pN2 received adjuvant chemotherapy. The median follow-up period was 51.6months. Postoperative recurrence was observed in 5 (28%) pN1 and 22 (61%) pN2 patients. One (6%) pN1 and 12 (33%) pN2 patients experienced locoregional recurrence. None of the pN1 patient experienced local recurrence at the dissected zone, whereas 11 (31%) pN2 patients had lymph node recurrence, including four at the dissected area and three in the area omitted from dissection in the lobe-specific MLND. The 5-year overall survival rates were 88.1% in the pN1 patients and 80.0% in the pN2 patients; the 5-year recurrence-free survival rates were 63.9% in the pN1 patients and 34.8% in the pN2 patients. In pN2 patients, pathological T classification was a prognostic factor for overall survival (P<0.001) and recurrence-free survival (P=0.034), and single-station N2 disease was also prognostic factor for overall survival (P=0.023). CONCLUSIONS: Recurrence at the omitted zone is an issue for this type of MLND. For pN1 patients, adequate MLND is an important factor for curative treatment. However, for pN2 patients, systemic treatment after recurrence may also contribute to survival.