Pyrotinib in the treatment of advanced lung adenocarcinoma with HER2 exon 20 mutation: a case report and literature review

The lung cancer poses a great threat to the patients' health and social activities. Luckily, epithelial growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs) have greatly improved the response of patients getting EGFR-mutated non-small cell lung cancer (NSCLC), but the targeted therapy of human epidermal growth factor receptor 2 (HER2) mutations in lung cancer is still being explored; however, the effectiveness of drugs for HER2-mutant NSCLC is unsatisfactory. This article reported the diagnosis and treatment of a case of advanced lung adenocarcinoma with erb-b2 receptor tyrosine kinase 2 (ERBB2, also known as HER2) exon 20 mutation. A 65-year-old women received concurrent chemoradiotherapy postoperatively after a lesion was found in her lung. A new metastatic lesion then appeared in the lung 8 months later and she diagnosed with stage IV lung adenocarcinoma; The gene detection found the patient carried a nonframeshift insertion mutation of HER2 exon 20, According to the test result, the patient received pyrotinib, and the new lesion in the lung disappeared soon. The progression-free survival (PFS) of the patient was up to 26 months. The clinical study reported a such successful application of pyrotinib in a patient with HER2-mutated advanced lung adenocarcinoma, the case indicated that pyrotinib may provide a longer survival time for such patients.