Brain metastasis effectively treated with erlotinib following the acquisition of resistance to gefitinib: a case report

INTRODUCTION: Non-small-cell lung cancer harboring an activated epidermal growth factor receptor mutation exhibits a good response to epidermal growth factor receptor-tyrosine kinase inhibitors; however, clinicians often experience treatment failure following the development of resistance to epidermal growth factor receptor-tyrosine kinase inhibitor. CASE PRESENTATION: We here report a case of a 56-year-old Japanese woman with non-small-cell lung carcinoma with a secondary T790M mutation associated with resistance to epidermal growth factor receptor-tyrosine kinase inhibitor that maintained sensitivity of brain metastases to epidermal growth factor receptor-tyrosine kinase inhibitor. An autopsy showed that the primary focus had a T790M mutation; however, no mutations of T790M were found in the brain metastases. CONCLUSION: This case demonstrates the detection of T790M was associated with the clinical responsiveness to epidermal growth factor receptor-tyrosine kinase inhibitor.