Therapeutic Outcomes of Osimertinib in EGFR - Mutant Non-Small Cell Lung Cancer With Brain Metastases: Results From a Retrospective Study at Vietnam National Cancer Hospital.

IntroductionThis study aimed to evaluate the therapeutic effect of osimertinib and further to compare the results of osimertinib plus brain radiation vs. osimertinib monotherapy in advanced EGFR-mutant non-small cell lung cancer (NSCLC) patients with brain metastases (BMs).MethodsA retrospective study was conducted involving 62 advanced EGFR-mutant NSCLC patients with BMs who were treated with first-line osimertinib at the Vietnam National Cancer Hospital between April 2019 and December 2023. Patients were categorised in two treatment groups: (1) osimertinib alone (33 patients) and (2) osimertinib combined with locoregional therapy, including stereotactic radiosurgery or whole-brain radiotherapy (29 patients). Endpoints included objective response rate (ORR), central nervous system response rate (CNS-ORR), progression-free survival (PFS), overall survival (OS).ResultsThe systemic ORR was 91.9% and the disease-control rate (DCR) was 96.8%. The CNS-ORR was 91.9% and the CNS-DCR was 100%. The median PFS and median OS achieved were 24.5 and 35.2 months, respectively. There was no significant difference in outcomes between patients in either treatment group with respect to CNS-ORR ( = 1.0), mean best percentage change from baseline in CNS target lesion size ( = .376), median PFS ( = .656), intracranial progression-free survival (iPFS) ( = .706), or OS ( = .734). The occurrence of any-grade adverse events (AEs) did not differ significantly between the two treatment groups ( = .762). However, in the osimertinib plus brain radiation cohort, 3/29 (10.3%) patients experienced radiotherapy-related AEs (2 cases of brain necrosis, 1 case of leukoencephalopathy), which consisted of one case of grade 3 brain radiation necrosis.ConclusionOsimertinib shows favorable real-world outcomes in improving PFS, OS, and CNS-ORR in advanced EGFR-mutant NSCLC Vietnamese patients with BMs, with no clear additional benefit from combining with brain radiotherapy.