Significant Intracranial Response and Long-term Survival after Pembrolizumab in Non-small Cell Lung Cancer Brain Metastases Resistant to Stereotactic Radiotherapy

Brain metastases from non-small cell lung cancer are typically managed with local therapies, such as surgery and radiotherapy, whereas systemic treatments have historically demonstrated limited efficacy in the intracranial setting. Immune checkpoint inhibitors, particularly programmed cell death-1 inhibitors, have recently demonstrated potential in this context. We report a case of a 48-year-old man with lung adenocarcinoma who developed a radiation-resistant brain metastasis with postoperative recurrence and severe neurological deterioration. Despite multiple courses of stereotactic radiosurgery and surgical resection, the lesion progressed, accompanied by seizures, impaired consciousness, and poor performance status.