P13.15 Multi-fraction stereotactic radiosurgery (MF-SRS) versus surgery plus MF-SRS for patients with large radioresistant brain metastases

Abstract

PURPOSE: Both surgery and radiosurgery (SRS) are frequently used in the initial management of patients with brain metastases. We have evaluated the local control and the radiation‐induced brain necrosis in patients with large resistant brain metastases (<2 cm in size) who received multi‐fraction stereotactic radiosurgery (MF‐SRS) or surgery followed by MF‐SRS. PATIENTS AND METHODS: Patients with renal cell carcinoma and melanoma brain metastases < 2 cm in size treated with MF‐SRS (3 x 9 Gy) or surgery + MF‐SRS to resection cavity were analyzed. The primary end point of the study was the local control. RESULTS: Between from March 2005 to June 2015, a total of 91 patients (MF‐SRS, 46 pts; surgery + MF‐SRS, 45 pts) were evaluated in this study. The median survival times were 13.2 months and 16.1 months in MF‐SRS and surgery + MF‐SRS groups, respectively (p = 0.03) and months. The 6‐month and 12‐month local control rates were 82% and 63% after MF‐SRS and 91% ad 83% after surgery + MF‐SRS (p = 0.01), respectively; the 1‐year incidence of new distant brain metastases were 53% and 45%, respectively (p = 0.1). Nine patients undergoing surgery + MF‐SRS and 4 subjected to MF‐SRS experienced brain radionecrosis (p=0.1), as suggested by magnetic resonance imaging (MRI) and (F‐DOPA) PET‐CT imaging. According to RTOG Common Toxicity Criteria, neurological grade 3 toxicities due to brain radionecrosis was similar between groups (MF‐SRS, 2 pts; surgery + MF‐SRS, 4 pts). For both groups, the target volume and the volumes of normal brain receiving doses of 18‐21 Gy were predictive of radionecrosis. CONCLUSIONS: For patients with large resistant brain metastases, surgery plus MF‐SRS is an effective treatment modality associated with better local control as compared with MF‐SRS alone. These results need to be confirmed in prospective randomized studies.