Secondary brain neoplasm after stereotactic radiosurgery in patients with metastatic non-small cell lung cancer

Stereotactic radiosurgery (SRS) using the Gamma Knife (GK) is now being increasingly utilized for the treatment of brain metastases. However, there are a few reported cases of SRS-induced brain neoplasms. We herein report the case of a Japanese woman with metastatic non-small cell lung cancer (NSCLC) harboring epidermal growth factor (EGFR)-mutations who was treated four times with a GK for brain metastases. She developed glioblastoma 5.7 years after the initial GK surgery. Radiation-induced secondary neoplasms generally appear after a latency period of several years. Advances in cancer therapy have improved the survival of patients with NSCLC, providing enough time for secondary neoplasms to appear after SRS.