Great efficacy of afatinib on a patient with lung adenocarcinoma harboring uncommon EGFR delE709_T710insD mutations: a case report.

EGFR)-targeted drugs have been the first-line treatment for patients with -mutant non-small cell lung cancer (NSCLC), especially exon 19 deletions and L858R mutation in exon 21. However, there is insufficient evidence for other less common types of mutations, such as delE709_T710insD (del 18). Recent studies have revealed that these rare genotypes could be targetable if appropriate mutations, such as delE709_T710insD (del 18). Recent studies have revealed that these rare genotypes could be targetable if appropriate EGFR tyrosine kinase inhibitors are selected. Here we reported a stage Ⅳ NSCLC patient with delE709_T710insD mutation who responded well to afatinib, a second-generation TKI. Afatinib had taken good control of the patient's brain metastasis with a progression-free survival of 11 months and an overall survival exceeded 21 months, although he had received multi-line therapy. This case demonstrates delE709_T710insD is a rare but potentially afatinib responsive mutation in NSCLC, which may contribute to changes in clinical practice and further research into the precise detection and treatment of rare mutations in .