P1.18-25 The Impact of Radiation Pneumonitis on Prognosis of Patients with Locally Advanced Non-Small Cell Lung Cancer Treated with Chemoradiotherapy

Abstract

Concurrent chemoradiotherapy (CRT) is the standard treatment for patients with locally advanced non-small cell lung cancer (LA-NSCLC). The radiation pneumonitis after CRT is one of the most serious problems in clinical practice. Moreover, the prognosis of the patients with driver mutation who received CRT remains unclear. The medical records of LA-NSCLC patients treated with CRT at Hirosaki University Hospital and Aomori Prefectural Central Hospital between January 2008 and June 2018 were reviewed. This study was approved by the ethics committee of Hirosaki University Graduate School of Medicine (No. 2018-1157). A total of 257 patients were enrolled. The median age was 67 years (range, 36-84). One hundred six patients (41.2%) had adenocarcinoma, 130 (50.6%) squamous cell carcinoma, and 21 (8.2%) NSCLC not otherwise specified. Response rate was 79.4%. Median progression free survival (PFS) was 13.6 months (95%CI: 11.3-17.8 months) and median overall survival (OS) was 64.2 months (95%CI: 47.5-122.5). There was no difference in PFS between the histological subtypes. Thirteen patients had EGFR mutation. The median PFS after CRT was not significantly different between EGFR mutant and wild type (9.0 vs 11.9 months, p= 0.831). The 2- and 5-yrear OS rate was 66.4% and 47.5%, respectively. Pneumonitis within 42 days after CRT was observed in 84 patients (32.7%), of whom 28 (10.9%) showed grade 3 or over. After 42 days of CRT, 133 patients (51.8%) developed pneumonitis. The patients with radiation pneumonitis within 42 days after CRT had a significantly shorter OS than those who developed pneumonitis after 42 days (38.6 vs 122.5 months, p=.0002). Pulmonary emphysema and fibrosis on baseline CT were correlated with radiation pneumonitis of grade 3 or more. Radiation over 60 Gy significantly prolonged OS than the lower dose (median OS: 64.3 vs 10.1 months, p=0.0002). Early pneumonitis after CRT might be suggestive of a poor prognosis, and the EGFR mutation status might not affect PFS after CRT.