Boswellia serrata for cerebral radiation necrosis after radiosurgery for brain metastases.

Abstract

Background: Radiation necrosis(RN) is a dose-limiting toxicity of stereotactic radiosurgery(SRS) for brain metastases. Oral corticosteroids are not optimal for long-term management given multiple side effects. Boswellia serrata(BS) is an over-the-counter supplement traditionally known for anti-inflammatory properties and recently shown to reduce cerebral edema. We evaluated the response rates with BS in a series of patients with RN after SRS for brain metastases.

Methods: We identified patients who developed any grade RN after SRS and received BS for ≥2 months, at a target dose of 4050-4500 mg daily. Primary endpoint was objective response rate(ORR), including complete response(CR) or partial response(PR), defined as ≥30% decrease in edema volume on T2-FLAIR MRI from baseline.

Results: 100 patients received BS of which 94 patients with adequate follow-up were included. Median SRS dose was 24 Gy in 3 fractions, and 44%, 47% and 9% patients had grade 1, 2, and 3 RN, respectively. The best response was CR in 12% and PR in 48%, while 28% had stable edema(SE) and 12% had progression of edema. The overall ORR was 59.6% (95% CI: 48.9 - 69.6%). ORR was 62%, 63%, and 33%, respectively for grade 1, 2, and 3, RN. The median duration of response in patients with CR or PR was 13.9 months (IQR 9 - 23). Among 69 patients (73%) who never received steroids, received prior steroids only, or had a stable or decreasing steroid requirement of ≤4 mg per day of Dexamethasone for at least >1 week prior to starting Boswellia, the ORR was 63.8%. 14% patients had CTCAE grade 1, and 2% had grade 2 gastrointestinal toxicity. 67% patients remained on BS at last follow-up.

Conclusion: Our study suggests BS is a safe and feasible treatment option for grade 1-3 RN after SRS. Further prospective studies comparing BS with placebo are warranted.