Whole brain radiation therapy with or without stereotactic radiosurgery boost for patients with one to three brain metastases: phase III results of the RTOG 9508 randomised trial

Abstract

This study aims to assess efficacy of a 15-Gy margin dose in terms with the hypothesis that efficacy will be comparable with historical controls with fewer radiation-related side effects.Patients who received single-fraction stereotactic radiosurgery (SRS) for metastatic brain tumors (prescribed 1500 cGy with 2-mm planning tumor volume) at the University of Missouri Hospital between 2004 and 2018 with at least 3 months of follow-up were retrospectively reviewed. Demographics, lesion dimensions, concurrent therapy, and treatment history before SRS were assessed. Outcomes included local control, distant control, radiation-related changes, survival, repeat SRS or whole-brain radiation therapy, and side effects. Data from the literature were pooled for a meta-analysis.A total of 142 patients had at least 3 months of follow-up data available. The 12-month actual local control rate among these patients was 92% per tumor. The overall intracranial control rate was 66.9% per patient. Radiation-related side effects occurred in 32.4% of patients (n = 46), with some patients having more than 1 side effect. Radiation-related radiographic changes occurred in 48 lesions (10.6%) in 37 patients (26%). Pathologically confirmed radiation necrosis occurred in 19 lesions (4%) and in 18 patients (12.6%). Local and distant control rates for this population was comparable with historical controls. Side effects in the literature are inconsistently reported, so rigorous comparative analysis is not possible.A single-fraction radiosurgery margin dose of 15 Gy to the planning tumor volume can effectively provide local control and distant control and is comparable with historical controls, which use 18–25 Gy, with a good toxicity profile.