P1.07-017 Indications for Adjuvant Mediastinal Radiation in Surgically Resected Small Cell Lung Cancer

Abstract

Adjuvant mediastinal radiation (AMR) is an adjunctive therapy for patients with surgically resected small cell lung cancer (SCLC). However, little data guides its use. We sought to examine whether there was a survival benefit associated with AMR for resected SCLC patients and to define sub-populations who should be selected for AMR. Patients undergoing resection (lobectomy, pneumonectomy and sublobar resection) for SCLC were identified in the National Cancer Database, 2004 – 2013. Kaplan-Meier survival curves and Cox proportional hazards were used to evaluate the impact of receipt of AMR on survival. Hazard ratios were adjusted for patient comorbidity and demographic information, as well as tumor stage, grade, histology, margin status and receipt of adjuvant chemotherapy. 3,113 patients were identified. Those receiving AMR were younger, more likely to have greater pathologic T- and N- stage, more likely to undergo sublobar resection and have a positive margin. Kaplan-Meier curves showed better median survival for patients with N1-3 disease who received AMR. After adjustment, Cox models showed lower risk of death for N1, N2/3 and sublobar resection with AMR (HR0.79 CI0.65 – 0.96, p=0.02; HR 0.60 CI0.48 – 0.75, p<0.0001). In the overall cohort, AMR was not associated with better survival in node-negative patients. AMR was, however, associated with improved survival for patients receiving sublobar resection (HR0.72 CI0.58 – 0.92, p=0.006). AMR has significant benefit for node-positive patients after resection for SCLC, especially those with pN2 or pN3. Patients undergoing sublobar resection may benefit from AMR.