Clinical impact of rebiopsy among patients with epidermal growth factor receptor‐mutant lung adenocarcinoma in a real‐world clinical setting. Issue 6 (2nd February 2021) - Nam, Yunha
Abstract: Background: In this study, we investigated the risk factors of acquired T790M mutation among patients with lung adenocarcinoma with epidermal growth factor receptor (EGFR) tyrosine mutation who were treated with EGFR‐tyrosine kinase inhibitors (TKIs). The aim was to identify the clinical impact of rebiopsy. Methods: This multicenter, retrospective cohort study was conducted in South Korea from January 2007 to June 2017. Patients with adenocarcinoma with EGFR mutation who underwent rebiopsy and were treated with EGFR‐TKIs were included. Results: Of a total of 352 patients, T790M mutation was identified in 156 (41.9%) at the time of rebiopsy. The median duration from initial biopsy to rebiopsy was 17 months. Univariate logistic regression analysis revealed associations of exon 19 deletion (odds ratio [OR], 1.643; p = 0.026), absence of L858R (OR, 0.627; p = 0.042), and previous EGFR‐TKI treatment duration (OR, 1.039; p < 0.001) with T790M mutation. Previous EGFR‐TKI treatment duration (OR, 3.580; p < 0.001) was independently associated with T790M mutation. A multivariate Cox proportional hazard model revealed that brain metastasis at initial diagnosis (hazard ratio, 1.390; p = 0.050) tended to be associated with T790M mutation. Among the patients with T790M mutation at rebiopsy, the osimertinib user group ( n = 90) had a better one‐year survival (68.7 vs. 58.3%, p = 0.048) than the osimertinib nonuser group ( n = 66). Conclusions: Rebiopsy might affect the clinical course of patients with EGFR ‐mutant adenocarcinoma who receive EGFR‐TKIs. Abstract : In this multicenter retrospective study, whereas exon 19 deletion, the absence of L858R, previous EGFR‐TKI treatment duration and brain metastasis at initial diagnosis were associated with acquired T790M mutation, a previous EGFR‐TKI treatment duration was independently associated with acquired T790M mutation. However, the acquired T790M mutation group had improved survival compared to the T790M mutation‐negative group. In particular, the osimertinib user group had a better one‐year survival than the nonuser group among patients with acquired T790M mutation.