Afatinib and osimertinib in lung adenocarcinoma harbored EGFR T751_I759delinsS mutation: A case report.

Tyrosine kinase inhibitors (TKIs) of epidermal growth factor receptor (EGFR) are the standard treatment for lung cancer patients with activating EGFR mutation. The traditional direct polymerase chain reaction (PCR) has lower sensitivity in the detection of EGFR mutations in patient tissue samples. Whilst PCR amplification kits increase the sensitivity in detecting some types of EGFR mutations, not many types of rare mutations are found. Here, we report a patient who had lung adenocarcinoma harboring EGFR T751_I759delinsS mutation and had good response to afatinib initially and osimertinib after developing resistance to afatinib. This rare EGFR mutation was not detected by Scorpion and ARMS method but was found using the next-generation sequencing method. There are less prospective trials in the treatment of lung adenocarcinoma with very rare EGFR mutations. Our case report could therefore provide clinical experience to the clinicians in the management of their patients.