Durvalumab completion and re-administration after grade 2 radiation pneumonitis following concurrent chemoradiotherapy for unresectable stage III NSCLC: a single-center real-world study

This study evaluated the incidence and clinical impact of radiation pneumonitis (RP) in patients with unresectable stage III non-small cell lung cancer (NSCLC) treated with durvalumab following concurrent chemoradiotherapy (CCRT), with a particular focus on durvalumab interruption, re-administration, and overall survival (OS). This retrospective study included patients treated at our institution between April 2018 and June 2024. Durvalumab was administered for up to one year or until discontinuation due to adverse events or disease progression. RP was graded according to CTCAE version 5.0. Associations between grade ≥ 2 RP and clinical or treatment-related factors were assessed using univariate and multivariate analyses. Survival outcomes were analyzed using the Kaplan–Meier method and Cox proportional hazards models. Among 101 patients, 48 (47.5%) developed grade ≥ 2 RP (grade 2: 41.6%; grade 3: 4.0%; grade 4: 2.0%). Lung V20 > 30% was independently associated with grade ≥ 2 RP. Durvalumab interruption occurred in a subset of patients with grade 2 RP; among these patients, 25 (59.5%) were able to undergo durvalumab re-administration, with RP recurrence observed in only one patient after re-administration. The 2-year and 3-year OS rates were 75.1% and 60.9%, respectively. Completion of durvalumab was the strongest independent predictor of OS (hazard ratio 0.14; P = 0.00007), whereas grade ≥ 2 RP itself was not significantly associated with OS. In this real-world cohort, completion of durvalumab consolidation after CCRT was strongly associated with improved OS in patients with stage III NSCLC. Although grade ≥ 2 RP was a frequent complication, temporary interruption and re-administration were feasible in selected patients. However, these findings should be interpreted cautiously because of the retrospective design and potential residual confounding.