Introduction
NSCLC, cancer, Lung cancer, tumour, deaths
INFILTRATION, ADVERSE EVENTS, CANCER, LUNG CANCER, TUMOUR, NSCLC
Lung cancer is one of the main contributors to the global cancer burden with an estimated 2.21 million new cases and 1.79 million deaths worldwide in 2020 [Assessment of therapeutic efficacy in patients with NSCLC ismainly based on radiographic scans. This evaluation method has its limitations when monitoring immunotherapy response. Checkpoint inhibitors sometimes cause a transient increase in tumour size due to infiltration of immune cells, pseudoprogression and response to ICIs on CT scans can be delayed [Cell‐free DNA (cfDNA) are degraded fragments of cellular DNA, usually 140–200 base pairs in length, found in the circulation of both healthy and diseased individuals [In this study, we investigated the combination of a PD‐L1 inhibitor, atezolizumab and radiotherapy in chemotherapy‐pretreated patients with advanced NSCLC. We here present the clinical outcomes, including therapeutic responses and adverse events, as well as mutations detected in ctDNA, changes in ctDNA during treatment and how they relate to therapy responses at an individual level.