NCOG-01. STEREOTACTIC RADIOSURGERY FOR BRAIN METASTASES AT THE GUY’S CANCER CENTER, LONDON: AN AUDIT FOR THE FIRST 17 MONTHS

Abstract

Abstract INTRODUCTION Stereotactic radiosurgery (SRS) commenced at Guy’s Cancer Hospital in August 2017. We report our first seventeen months’ data (August 2017 to December 2018) for brain metastases SRS. METHOD Patients referred via Neuro Oncology MDT were assessed for suitability for SRS via clinical review and 1mm-slice MRI. Treatment was planned on Eclipse v15.6 and delivered using Truebeam STx Linac(FFF) and Align RT v5.1 for matching. Dose prescription, according to departmental protocol, was set at 100% isodose, ranging from 18Gy to 25Gy, with fractionation varying from single to five fractions depending on factors including size, volume and locations. Post-treatment, patients were discharged back to their primary treating team for 3-monthly MRI. RESULTS Between Aug-17 to Dec-18, 70 patients with brain metastases were treated with a total of 122 lesions. Mean age was 66 years (range 37-93) and Median follow-up 9 months. Primary tumour sites mainly included lung 34(48.5%), breast 16(22.8%) and melanoma 17(24.3%). Brain-only metastases, including small volume primary with brain metastases were found in 85.4% cases, whilst visceral disease with brain metastases were found in 14.5% patients. Out of 122 lesions, the majority were treated in the primary setting; 95(77.8%) vs 27(22.1%) in the adjuvant setting. At 9-months follow up, local failure rate was in 26(21.3%) sites and 17 new sites in distant brain appeared. 31(44.2%) patients received no systemic therapy after SRS, whilst immunotherapy was received by 14(20%), with the remaining receiving hormones or chemotherapy. Median Overall Survival was 9.2 months (95% CI: 4.5-13.8) and Median progression-free survival was 5.9 months (95% CI: 7.0-10.4). CONCLUSION Overall Survival results were encouraging with initial auditing proving SRS as effective approach. Local control rates correlate well with randomized control trials results for SRS in brain metastases.