Sequential Pneumonitis with Ground-glass Opacity during Durvalumab Therapy after Chemoradiation for Stage III Non-Small Cell Lung Cancer

Abstract Background: To investigate the clinical characteristics, radiographic pattern, and clinical course of radiation pneumonitis and programmed death ligand 1 inhibitor-related pneumonitis in patients with stage III non-small cell lung cancer (NSCLC) after definitive concurrent chemoradiotherapy (CCRT). Methods: We retrospectively reviewed 22 patients who received definitive CCRT and consolidative Durvalumab for NSCLC between February 2018 and December 2019 at our hospital. Chest computed tomography scans were reviewed to assess the incidence, timing, relation to the field of radiotherapy, and radiographic patterns of pneumonitis. Results: Among the 22 patients, six (27.3 %) developed grade 2 radiation pneumonitis. The median time from therapy initiation to pneumonitis was 1.5 months. Three patients had pneumonitis within the radiation treatment field, and the other three had pneumonitis spread outside the field. The radiographic pattern was organizing pneumonia with ground-grass opacity in five patients. All patients received corticosteroid therapy, and no patient experienced progression to grade 5 pneumonitis or recurrent pneumonitis after Durvalumab retreatment. Conclusion: It is essential to understand the mechanism and radiographic pattern of immunotherapy-related pneumonitis and radiation pneumonitis to manage this potentially severe adverse event promptly.