Afatinib as first‐line treatment for advanced lung adenocarcinoma patients harboring HER2 mutation: A case report and review of the literature

HER2 mutations are a rare group of driving genes that respond to HER2 targeted therapy, particularly afatinib. No more than 20 such cases have been reported, but afatinib was used after first‐line chemotherapy. We present the case of a never‐smoking female patient diagnosed with stage IV lung adenocarcinoma harboring a Her2 exon 20 inserted mutation who achieved a durable response (12 months) to first‐line afatinib treatment. We review the literature concerning afatinib therapy in this rare cohort of mutated lung cancer patients.