P2.02-053 Does the Method of Mediastinal Staging Cause the Mediastinal Nodal Clearance Following Trimodality Therapy?

Abstract

Outcomes of trimodality therapy for patients with persistent N2 have been well-known as grave. The aim of our study was to investigate whether the method of mediastinal staging could influence the mediastinal nodal clearance following trimodality therapy. We retrospectively reviewed medical records of 574 patients with clinical stage IIIA-N2 non-small cell lung cancer who underwent surgery after neoadjuvant CCRT from 1997 to 2013. Clinical outcomes were analyzed and compared in those who had EBUS (n = 147), Mediastinoscopy (n = 341), and others (n = 86) after neoadjuvant CCRT in a single institution. The median number of dissected lymph node during the operation was 20 (range, 0-50) in EBUS, 14 (range, 1-52) in mediastinoscopy, and 18 (range, 4-40) in others (p<0.001). The median number of lymph node metastases was 2 (range, 0-23) in EBUS, 1 (range, 0-26) in mediastinoscopy, and 0 (range,0-14) in others (p<0.001). There were no differences of age, sex ratio, cell type, surgical extent, clinical T stage, and bulk N2 between these groups. The mediastinal nodal clearance rate (ypN0/1) after surgery was 36 % (54/147) in EBUS, 58% (198/341) in mediastinoscopy, and 60.5% (52/86) in others (p<0.001). The ypN0 rate was 28.6% (42/147) in EBUS, 41.9% (143/341) in mediastinoscopy, and 51.2% (44/86) in others (p=0.001). We found that the mediastinal nodal clearance rate (ypN0/1) after surgery was higher in mediastinoscopy than in EBUS. The method of mediastinal staging could influence ypN stage following trimodality therapy.