CMET-01. IMMUNE CHECKPOINT INHIBITORS FOR NON-SMALL CELL LUNG CANCER WITH BRAIN METASTASIS: THE ROLE OF GAMMA KNIFE RADIOSURGERY

Abstract

Abstract PURPOSE Immune checkpoint inhibitors (ICIs) are approved for the treatment of non-small cell lung cancer (NSCLC), but the safety and efficacy of the combined treatment with ICIs and gamma knife radiosurgery (GKS) remain undefined. METHODS We retrospectively reviewed the medical records of patients with brain metastases from NSCLC who were treated with ICIs between January 2015 and December 2017 at our institute. Of the 134 patients identified, 77 who were assessable for brain responses were categorized into three groups based on the medication administered and GKS: Group A, ICI alone; Group B, ICI with concurrent GKS within 14 days; and Group C, ICI with non-concurrent GKS. RESULTS The median follow-up duration after the diagnosis of brain metastases was 19.1 (range, 1–68.7) months. At the last follow-up, 48 patients (62.3%) died. The overall survival was shorter in Group A than in Groups B and C (P=0.001). There were no statistically significant differences in the intracranial disease progression-free survival (P=0.514), local progression-free survival (P=0.358), and complication rates among the three groups. Twelve patients presented with leptomeningeal seeding (LMS) during follow-up. There was a significant difference in the LMS-free duration from the time of administering ICIs (P=0.011) and the diagnosis of metastasis (P< 0.001). CONCLUSION GKS in combination with ICI showed no favorable overall survival outcome in the treatment of brain metastasis from NSCLC. However, GKS with ICI did not increase the risk of complications. Furthermore, compared with ICI alone, GKS with ICI may be associated with a reduced incidence of LMS.