A case of lung adenocarcinoma wtih exon19 and T790M mutations in EGFR having good response to erlotinib after gefitinib treatment failure

: A 83-year-old woman was referred to our hospital due to an abnormal shadow in the right lower lung field and pleural effusion on chest X-ray. Cytology of the pleural fluid showed adenocarcinoma. EGFR sequencing showed exon19 and T790M mutations. Gefitinib was prescribed as first-line treatment for stage IV(pulmonary metastasis)lung adenocarcinoma from March 2011. The response to the treatment was improved pleural effusion and shrunken tumors. She showed recurrence 13 months after administration of gefitinib. Erlotinib was given as second-line treatment from May 2012. She showed good response with shrinkage of the pulmonary metastases, and was alive with no sign of recurrence for 3 months after administration of erlotinib.