Predictors of lung injury during durvalumab maintenance therapy following concurrent chemoradiotherapy in unresectable locally advanced non‐small cell lung carcinoma

BACKGROUND: Based on the results of the PACIFIC trial, maintenance with durvalumab has emerged as the standard treatment following concurrent chemoradiotherapy in patients with unresectable locally advanced non‐small cell lung carcinoma (NSCLC). However, adverse events attributed to durvalumab, especially lung injuries, including immune‐related adverse events, and radiation pneumonitis, are concerning. This study retrospectively investigated the factors related to lung injury in patients receiving the PACIFIC regimen. METHODS: Patients with unresectable locally advanced NSCLC who received durvalumab maintenance therapy following concurrent chemoradiotherapy at Yokohama City University Medical Centre between July 2018 and March 2022 were included. Clinical data, volume of normal lung receiving 20 or 5 Gy or more (V20 or V5), planning target volume (PTV), and relative lung parenchyma volume in emphysematous lung receiving 20 or 5 Gy or more (RLPV20 or 5; V20 or V5/100‐percentage of low‐attenuation volume) were evaluated. RESULTS: Performance status (PS), V20, V5, PTV, RLPV20, and RLPV5 were significantly higher in the lung injury group in the univariate analysis. Furthermore, RLPV20 was the most significant factor in the lung injury group in the multivariate analysis comprising PS, PTV, V20, and RLPV20. CONCLUSION: RLPV20 and RLPV5 are useful in estimating lung inflammation. RLPV20 could be considered the most reliable risk factor for maintenance therapy with durvalumab following concurrent chemoradiotherapy in patients with unresectable locally advanced NSCLC.