[A Case of Multiple Brain Metastases after Surgery for Lung Cancer Successfully Treated with Osimertinib]

Right upper lobectomy and lymph node dissection was performed on an 85-year-old male clinically diagnosed with primary lung cancer at the age of 78 years. His post-operative pathologic staging was adenocarcinoma pT1aN0M0, StageⅠ A1, and he was positive for the epidermal growth factor receptor(EGFR). Two years post-operation, a PET scan revealed cancer recurrence due to mediastinal lymph node metastasis. The patient received mediastinal radiation therapy followed by cytotoxic chemotherapy. Nine months later, a PET scan revealed bilateral intrapulmonary metastases and metastases to the ribs. He was subsequently treated with first-generation EGFR-TKIs and cytotoxic chemotherapy. However, his performance worsened 30 months later(6 years post-surgery)due to multiple brain metastases and tumor hemorrhage. Therefore, invasive biopsy was problematic, and liquid biopsy(LB)was performed instead. The results showed a T790M gene mutation, and osimertinib was administered to treat the metastases. The brain metastasis decreased, and PS improved. Thus, he was discharged from the hospital. Although the multiple brain metastases vanished, a CT scan showed liver metastasis 1 year and 6 months later. As a result, he died 9 years post-surgery. Conclusion: The prognosis for patients with multiple brain metastases after lung cancer surgery is poor. Long-term survival is expected with 3rd generation TKI treatment if LB is performed appropriately, even in post-operative multiple brain metastases of EGFR-positive lung adenocarcinoma with poor PS.