Stereotactic Radiosurgery Results in Non-Small-Cell Lung Cancer Patients with Brain Metastases in the Era of Modern Systemic Treatment Agents

OBJECTIVE: This study reports the results of stereotactic radiosurgery and fractionated stereotactic radiosurgery treatment for brain metastasis in non-small cell lung cancer patients treated with modern systemic treatment methods (immunotherapy, targeted agents, and current chemotherapy agents). MATERIAL AND METHODS: This study retrospectively analyzed patients diagnosed with non-small cell lung cancer and brain metastases who underwent stereotactic radiosurgery/fractionated stereotactic radiosurgery in the Radiation Oncology Clinic of Ankara Bilkent City Hospital between February 21, 2019, and August 15, 2022. The study's primary endpoint was accepted as the lesions' response status after stereotactic radiosurgery/fractionated stereotactic radiosurgery.The secondary endpoint was accepted as the patients' intracranial progression-free survival and overall survival. RESULTS: This study included 85 patients treated for 174 lesions. Their median follow-up was 6.6 (range: 1-42) months.Their median intracranial progression-free survival after radiotherapy was 5.3 (range: 1-33) months, and their median overall survival was 6.6 (range: 1-42) months. Concurrent immunotherapy was administered to 10 (11%) patients and targeted therapy to 8 (9%). Magnetic resonance imaging indicated that 14 (6%) patients had a complete response, 62 (35.6%) had a partial response, 10 (5.7%) had stable disease, and 23 (13.2%) had progressive disease. The complete response rate was significantly higher in patients receiving targeted therapy (P <.001; odds ratio = 0.0025, 95% CI = 0.006-0.109). Intracranial recurrence was observed in 28 (32.9%) patients after stereotactic radiosurgery/ fractionated stereotactic radiosurgery: 7 (8.2%) were inside the radiotherapy field, 13 (15.3%) were outside the radiotherapy field, and 8 (9.4%) overlapped the radiotherapy field. Intracranial progression-free survival was higher in patients receiving concomitant immunotherapy (P =.028; hazard ratio = 0.107, 95% CI = 0.015-0.783). However, overall survival was higher in patients receiving targeted therapy (P =.035; hazard ratio = 0.217, 95% CI = 0.053-0.897). CONCLUSION: Using current systemic agents with radiotherapy for brain metastasis significantly affected post-radiotherapy intracranial progression-free survival.