Epidermal growth factor receptor tyrosine kinase inhibitors for de novo T790M mutation: A retrospective study of 44 patients

Background This study aimed to evaluate possible treatment strategies for patients with de novo T790M mutation‐positive (T790M+) non‐small‐cell lung cancer (NSCLC). Methods Patients diagnosed with de novo T790M+ NSCLC and treated with epidermal growth factor receptor tyrosine kinase inhibitors (EGFR‐TKIs) between 2011 and 2018 at a regional hospital in Taiwan were retrospectively reviewed. Their clinicopathological characteristics and subsequent treatment information were collected, and potential prognostic factors were identified using univariate and multivariate analyses. Results All tumors with T790M mutations coexisted with sensitizing mutations. Through the last follow‐up in May 2021, afatinib and osimertinib demonstrated better progression‐free survival (PFS, p