Retrospective study of boswellia serrate for cerebral radiation necrosis after radiosurgery for brain metastases

Radiation necrosis (RN) is a dose-limiting toxicity of stereotactic radiosurgery (SRS) for brain metastases. Boswellia serrata (BS) is an over-the-counter supplement known for anti-inflammatory properties and recently shown to reduce cerebral edema. A retrospective study at The Ohio State University (Columbus) evaluated BS among patients with RN after SRS for brain metastases; median SRS dose was 24 Gy in 3 fractions, and 44%, 47%, and 9% had grade 1, 2, or 3 RN, respectively. Patients received BS for at least 2 months, at a target dose of 4050 -4500 mg daily. Best response to BS was complete response in 12% and partial response (≥ 30% decrease in edema volume on T2-FLAIR MRI from baseline) in 48%, while 28% had stable edema and 12% had progression of edema. The overall ORR was 59.6% (95% CI 48.9-69.6) with ORR 62%, 63%, and 36%, respectively, in patients with grade 1, 2, and 3 RN. The median duration of response in patients with complete or partial response was 13.9 months (IQR 9-23). Gastrointestinal toxicity grade 1 was observed in 14% of patients and grade 2 in 2%. The authors conclude that the study suggests that BS is a safe and feasible treatment option for grade 1-3 RN after SRS. Prospective studies comparing BS with placebo are warranted.