P2.08-01 Outcomes Following Gamma Knife Radiosurgery for Oligometastatic Brain Metastases in Patients with NSCLC at Leeds Cancer Centre

Abstract

Gamma knife (GK) radiosurgery has increasingly been used for brain metastases from NSCLC in the oligometastatic setting. This study reports outcome results for patients with synchronous brain and new brain metastases from NSCLC at Leeds Cancer Centre (LCC). 251 patients, who were treated with GK at LCC from 2009 until 2018 were analysed. Retrospective analysis of notes was performed using electronic patient records. Statistical analysis was performed using SPSS. Kaplan-Meier curves were performed to estimate time to intracranial progression, survival from diagnosis of brain metastases, and overall survival. Median age was 65 years (range 33 – 90 years). For patients with new brain metastasis (147 patients), TNM stage at diagnosis was stage I (14 patients), stage II (42 patients), stage IIIA (26 patients) or stage IIIB/IV (65 patients). Histology was majority adenocarcinoma (59%), squamous cell carcinoma (16%) or NSCLC NOS (13%). Radical thoracic treatment (surgery, chemoradiotherapy or stereotactic ablative radiotherapy) was undertaken for 158 patients. 92% completed radical thoracic treatment. Median survival from diagnosis of brain metastases was 382 days (446 days for those with synchronous brain metastases (48 patients), and 325 days for those with new brain metastases (110 patients)). For all patients, median time to intracranial progression after GK was 242 days and overall survival after GK was 293 days. For patients with synchronous brain metastases at presentation (104 patients), median time for overall survival from date of diagnosis was 435 days. For all patients without brain metastases at presentation, median time to intracranial progression from date of diagnosis was 305 days and overall survival was 693 days. In conclusion, GK radiosurgery is an effective treatment for brain metastases in NSCLC, providing high rates of local control and improved survival. Beneficial effects are seen in patients with synchronous and new brain metastases, demonstrating its role in a wide subset of patients with advanced NSCLC. Use of GK, in combination with radical thoracic therapy, therefore has the potential to dramatically improve survival in patients who may not have previously been suitable for radical treatment.