A case report of a dramatic response to Afatinib in a patient with advanced adenosquamous carcinoma lung cancer (ASC) harboring EGFR L861R

Lung cancer is a malignant tumor with high incidence and mortality in China. Furthermore, non-small cell lung cancer(NSCLC) accounts for more than 85%. About 30-40% of Asian populations carry epidermal growth factor receptor (EGFR) gene mutations. EGFR mutations mainly occur in exon 18-21, and the common mutations are exon 19 deletions (19del), L858R, which are all sensitive to EGFR tyrosine kinase inhibitors(EGFR-TKIs). Nevertheless, the efficiency of the EGFR-TKIs on EGFR L861R remains unknown. In this article, we report a patient with adenosquamous carcinoma lung cancer(ASC) harboring EGFR L861R who was treated with afatinib and obtained progression-free survival(PFS) for more than 24 weeks.