Radiosurgery of limited brain metastases from primary solid tumor: results of the randomized phase III trial (NCT02355613) comparing treatments executed with a specialized or a C-arm linac-based platform

Abstract Background Comparative prospective data regarding different radiosurgery (SRS) modalities for treating brain metastases (BMs) from solid tumors are not available. To investigate with a single institute phase III randomized trial whether SRS executed with linac (Arm-B) is superior to a dedicated multi-source gamma-ray stereotactic platform (Arm-A). Methods Adults patients with 1–4 BMs from solid tumors up to 30 mm in maximum diameter were randomly assigned to arms A and B. The primary endpoint was cumulative incidence of symptomatic (grade 2–3) radionecrosis (CIRN). Secondary endpoints were local progression cumulative incidence (CILP), distant brain failure, disease-free survival (DFS), and overall survival (OS). Results A total of 251 patients were randomly assigned to Arm-A (121) or Arm-B (130). The 1-year RN cumulative incidence was 6.7% in whole cohort, 3.8% (95% CI 1.9–7.4%) in Arm-B, and 9.3% (95% CI 6.2–13.8%) in the Arm-A (p = 0.43). CIRN was influenced by target volume irradiated only for the Arm-A (p <