A SINGLE CENTRE 10-YEAR EXPERIENCE WITH GAMMA KNIFE STEREOTACTIC RADIOSURGERY FOR CEREBRAL METASTASES

Abstract

Abstract AIMS An estimated 20-40% of patients with metastatic cancer will have brain metastases, whose management depends on multiple factors. Stereotactic radiosurgery (SRS) is increasingly preferred to whole brain radio- therapy (WBRT), since it delivers a precise, high-dose of radiation to individual metastases. This study evaluated the 10-year experience of SRS at the Leeds Gamma Knife Centre. METHOD This is a retrospective, observational study of patients undergoing SRS between 2010 and 2020. Data on primary tumour, Karnofsky Performance Status (KPS), previous treatment for brain metastases, intracranial disease burden, oral steroid therapy, and toxicity were recorded. Follow-up was undertaken for a minimum of 6 months with regular MRI brain. RESULTS 3,940 intracranial metastases in 1,113 patients (478 male) were treated with SRS. Lung (48.2%) and breast (15%) were the most common primary tumours. Median survival was 10 months. Using multivariate analysis, primary diagnosis (p<0.001), KPS (p<0.001), number of lesions (p=0.005) and total tumour volume (p=0.012) were the most statistically significant predictors of survival. At follow-up, 375 (33.7%) patients had new brain metastases. Median time to new metastases was 6 months, and 195 (17.5%) patients underwent further SRS with a median time to repeat SRS of 7 months. Side effects following SRS were usually very mild, primarily including short-term fatigue (28.8%). Steroid dose also dropped significantly after SRS(p<0.001). CONCLUSIONS This 10-year analysis of SRS in brain metastases demonstrated a statistically significant association of survival with pre-treatment predictors, including primary diagnosis, KPS, intracranial disease burden. SRS provides minimal side effects with an associated significant decrease in steroid use following treatment.