2025 Targeted Therapies of Lung Cancer (TTLC) - Posters-PP01.10 Outcomes after Radiation Therapy for Oligoprogressive Disease in Patients with EGFR-mutant Metastatic Non-Small Cell Lung Cancer on Osimertinib

PP01.10 Outcomes after Radiation Therapy for Oligoprogressive Disease in Patients with EGFR-mutant Metastatic Non-Small Cell Lung Cancer on Osimertinib

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This study focused on the outcomes of radiation therapy (XRT) for patients with oligoprogressive disease (OPD) in EGFR-mutant metastatic non-small cell lung cancer (NSCLC) who were treated with osimertinib at Memorial Sloan Kettering Cancer Center. The cohort consisted of 81 patients, with a median age of 65 years, predominantly female and White. Osimertinib is a first-line treatment for EGFR-mutant advanced NSCLC, but resistance, often manifesting as OPD, emerges within two years.<br /><br />The study examined progression-free survival (PFS) and overall survival (OS) as primary endpoints, observing how XRT might prolong the clinical benefit of osimertinib. The median PFS was 6.9 months, and the median OS was 24.4 months. The median time on osimertinib post-XRT was 9.7 months. After XRT, 88% of patients experienced disease progression, with further systemic therapies undertaken by 62% of these patients.<br /><br />Interestingly, univariate analyses showed no significant associations between PFS and several baseline demographic, clinical, or molecular factors, suggesting that PFS was independent of pre-XRT duration on osimertinib, lesion characteristics, or molecular features. However, exon 19 deletions and T790M mutations in EGFR were positively correlated with improved OS, whereas atypical EGFR mutations were linked with poorer OS.<br /><br />This study underscores the potential of XRT to extend progression-free and overall survival in patients with oligoprogressive EGFR-mutant NSCLC on osimertinib. It highlights the need for further research to optimize the timing and application of local therapies and to better understand clinical and genomic predictors of treatment benefit.

Asset Subtitle

Sarah Lochrin

Keywords

radiation therapy

oligoprogressive disease

EGFR-mutant NSCLC

osimertinib

progression-free survival

overall survival

exon 19 deletions

T790M mutations

local therapies

clinical predictors