[Osimertinib Was Effective for Liver Metastasis after Surgery for Lung Cancer with Simultaneous Expression of EGFR L858Ra nd T790M Mutations-A Case Report].

A 63-year-old woman underwent right lower lobectomy and mediastinal dissection for lung cancer. At 5 years and 5 months after surgery, chest computed tomography revealed multiple liver metastasis. EGFR gene mutations of L858R and T790M were detected in both the primary lung cancer lesion and the liver metastasis specimen. Gefitinib was initiated as the first-line treatment, but the tumors increased in size. Osimertinib, as second-line treatment, was remarkably effective against the liver metastatic lesions and it maintained a partial response for approximately 1 year. Thus, osimertinib was effective for liver metastasis of lung cancer with EGFR mutations of L858R and T790M.