CLINICAL FACTORS PREDECTING T790M MUTATION IN NON-SMALL CELL LUNG CANCER PROGRESSED AFTER FIRST- AND SECOND-GENERATION TKI TREATMENT

Abstract

Objective: We aimed to identify the T790M mutation rate and clinical factors predicting the occurrence of acquired T790M mutations in advanced non-small cell lung cancer (NSCLC) patients with epidermal growth factor receptor (EGFR) mutations after first- and second-generation tyrosine kinase inhibitor (TKI) treatment. Method: The EGFR-mutant NSCLC patients who experienced progression after first- and second-generation TKI treatment and underwent testing for EGFR using plasma samples between January 2021 and April 2023 were enrolled. The T90M mutation rate and related clinical factors were evaluated. We utilized the Chi-square test or Fisher’s exact test for univariate analysis and multivariable logistic binary regression for multivariate analysis. Results: A total of 247 patients were eligible for the study. Patients harbored the exon 19 deletion mutation (Del19), exon 21 L858R point mutation, and uncommon mutations in 63.2%, 34.4%, and 2.4% of cases, respectively. The overall T790M mutation rate was 33.6%. In multivariate analyses, the Del19 mutation versus L858R mutation, duration of first-line TKI exceeding 12 months versus below 12 months, and solitary lesion progression versus multiple lesion progression were identified as favorable prognostic factors for the occurrence of T790M mutation. Conclusion: Patients with EGFR exon 19 deletion, a prolonged treatment duration of first-line EGFR-TKI, and solitary lesion progression pattern are more likely to acquire the T790M mutation, as detected by the PCR method in plasma samples.