Incidence and Risk Factors of Symptomatic Radiation Pneumonitis in Non–Small-Cell Lung Cancer Patients Treated with Concurrent Chemoradiotherapy and Consolidation Durvalumab

Consolidation durvalumab therapy following concurrent chemoradiotherapy is a new standard treatment for unresectable locally advanced non-small-cell lung cancer. Understanding the risk of radiation pneumonitis (RP) in this setting is important for both radiation treatment planning and the monitoring and management of patients. We found that elevations in lung volume receiving >= 20 Gy increased the RP risk. Introduction: Data on the risk factors for symptomatic radiation pneumonitis (RP) in non-small-cell lung cancer (NSCLC) patients treated with concurrent chemoradiotherapy (CCRT) and consolidation durvalumab are limited; we aimed to investigate these risk factors. Materials and Methods: This multicenter retrospective study, conducted at 15 institutions in Japan, included patients who were >= 20 years of age; who started definitive CCRT for NSCLC between July 1, 2018, and July 31, 2019; and who then received durvalumab. The primary endpoint was grade 2 or worse (grade 2+) RP.Results: In the 146 patients analyzed, the median follow-up period was 16 months. A majority of the patients had stage III disease (86%), received radiation doses of 60 to 66 Gy equivalent in 2-Gy fractions (93%) and carboplatin and paclitaxel/nab-paclitaxel (77%), and underwent elective nodal irradiation (71%) and 3-dimensional conformal radiotherapy (75%). RP grade 2 was observed in 44 patients (30%); grade 3, in four patients (3%); grade 4, in one patient (1%); and grade 5, in one patient (1%). In the multivariable analysis, lung V20 was a significant risk factor, whereas age, sex, smoking history, irradiation technique, and chemotherapy regimen were not. The 12-month grade 2+ RP incidence was 34.4% (95% confidence interval [CI], 26.7%-42.1%); the values were 50.0% (95% CI, 34.7%-63.5%) and 27.1% (95% CI, 18.8%-36.2%) in those with lung V20 >= 26% and < 26%, respectively (P=.007). Conclusion: The incidence of grade 2+ RP was relatively high in this multicenter real-world study, and its risk increased remarkably at elevated lung V20. Our findings can aid in RP risk prediction and the safe radiotherapy treatment planning. of grade 2+ RP was relatively high in this multicenter real-world study, and its risk increased remarkably at elevated lung V20. Our findings can aid in RP risk prediction and the safe radiotherapy treatment planning. (C) 2021 Elsevier Inc. All rights reserved.