NCMP-04. INITIAL REPORT OF BOSWELLIA SERRATA FOR MANAGEMENT OF CEREBRAL RADIATION NECROSIS AFTER STEREOTACTIC RADIOSURGERY FOR BRAIN METASTASES

Abstract

Abstract BACKGROUND Radiation necrosis(RN) is a concerning late toxicity after radiation therapy(RT) for brain metastases(BM). Oral corticosteroids are the mainstay of management; however, not optimal given multiple side effects, particularly with the emergence of immunotherapy. Boswellia serrata(BS) is an over-the-counter supplement shown to reduce cerebral edema after brain RT. We evaluated the response rates with BS in a series of BM patients treated with stereotactic radiosurgery(SRS) who developed RN. METHODS We enrolled patients who developed RN after SRS for BM from 2020-2022 and were treated with BS 4.2-4.5g daily. Response was assessed using Response Assessment in Neuro-Oncology(RANO) criteria. Primary endpoint was ≥25% decrease in edema volume on T2-FLAIR MRI from baseline. RESULTS Fifty patients received BS for Grade 1-3 CTCAE v5.0 RN (G1=11, G2=36, and G3=3). Median time to RN was 10 months(m) after SRS and median follow-up was 6m. Best response was a complete response(CR) in 15% patients and partial response(PR) in 40% while 35% had stable disease(SD) and 10% had progression. At 3 , 6 , 9 and 12 months of follow-up respectively, 25%, 60%, 43% and 50% patients had any response(CR or PR). About 56% patients had symptomatic RN, of which 35.7% had improvement in symptoms with BS alone, while 64% required steroid use. Overall, median duration of response in patients with CR, PR or SD was 7.5m(range 2-31m). Salvage treatment for RN was steroids(33), surgery(4), Bevacizumab(5) or hyperbaric oxygen(1). No patient had ≥ CTCAE grade 3 toxicities, while 6% had grade 1-2 gastrointestinal intolerance. Overall, 39 patients remained on BS at last follow-up or death. CONCLUSION We observed > 50% response rates with use of BS in patients with grade 1-3 RN after SRS. Over 1/3rd patients with symptomatic RN were able to avoid long-term steroid use. Further prospective studies comparing Boswellia with placebo are warranted.