Persistent N2 Following Induction Is Not a Contraindication to Surgery for Lung Cancer.

BACKGROUND: Surgery for potentially resectable stage IIIA-N2 non-small cell lung cancer(NSCLC) is controversial. For some, persistent N2 disease following induction therapy is a contraindication to resection. We examined outcomes of a well-selected surgical cohort of post-induction IIIA-N2 NSCLC patients with persistent N2 disease. METHODS: We retrospectively reviewed all resected clinical IIIA-N2 NSCLC patients from 2001-2018. Thorough pre-operative staging, including invasive mediastinal staging, was performed. Those with non-bulky N2 disease, appropriate restaging, and potential for a margin-negative resection were included. Post-resection, patients were classified as having persistent N2 disease or mediastinal downstaging (N2-\u3eN0/N1). Persistent N2 patients were further classified as uncertain resection[R(un)] or complete resection(R0) per IASLC definition. Kaplan-Meier survival analysis was utilized. RESULTS: 54 patients met inclusion criteria. Post-induction, 31(57%) patients demonstrated persistent N2 disease, 23(43%) patients had mediastinal downstaging. 98.1% underwent pre-induction invasive mediastinal staging. The majority had clinical single-station N2 disease(75.9%). 100% underwent margin-negative resections. Eight patients were reclassified as R(un) due to positive highest sampled mediastinal station. The median overall survival for persistent N2, was 26 and 69 months for R(un) and R0, respectively. Overall survival for the downstaged group was 67 months (p=0.31). CONCLUSIONS: Overall survival for patients with non-R(un), persistent N2 (true R0), was similar to those with mediastinal downstaging. Well-selected patients with persistent N2 disease experience reasonable survival post-resection and should have surgery considered as part of their multimodality treatment. This study underscores the importance of classifying the extent of mediastinal involvement for persistent N2 patients, supporting the proposed IASLC R(un) classification