Association of EGFR Exon 19 Deletion and EGFR-TKI Treatment Duration with Frequency of T790M Mutation in EGFR-Mutant Lung Cancer Patients

摘要

The most common event responsible for resistance to first- and second-generation (1st and 2nd) epidermal growth factor receptor (EGFR)-tyrosine kinase inhibitor (TKI) is acquisition of T790M mutation. We examined whether T790M is related to clinicopathologic or prognostic factors in patients with relapse of EGFR mutant non-small cell lung cancer (NSCLC) after treatment with 1st or 2nd EGFR-TKIs. We retrospectively reviewed the T790M status and clinical characteristics of 73 patients with advanced or recurrent NSCLC who had been treated with EGFR-TKIs and undergone rebiopsy at Kurume University Hospital between March 2005 and December 2015. T790M mutation was more frequent in patients with EGFR exon 19 deletion mutation (63%, 26/41) than in those with L858R mutation (38%, 12/32) (p?=?0.035). The median total duration of 1st or 2nd EGFR-TKI treatment was significantly longer in patients with T790M mutation than in those without (15.3 months vs 8.1 months, p??0.001). Multivariate analysis revealed that the type of EGFR mutation and the total duration of EGFR-TKI treatment were significantly associated with T790M prevalence. Patients with EGFR exon 19 deletion mutation who receive long-term EGFR-TKI therapy show a high prevalence of T790M mutation. The present data are potentially important for clinical decision-making in NSCLC patients with EGFR mutation.