Patients irradiated for brain tumors often suffer from cerebral edema and are usually treated with dexamethasone, which has various side effects. To investigate the activity of Boswellia serrata (BS) in radiotherapy-related edema, we conducted a prospective, randomized, placebo-controlled, double-blind, pilot trial.

Forty-four patients with primary or secondary malignant cerebral tumors were randomly assigned to radiotherapy plus either BS 4200 mg/day or placebo. The volume of cerebral edema in the T2-weighted magnetic resonance imaging (MRI) sequence was analyzed as a primary endpoint. Secondary endpoints were toxicity, cognitive function, quality of life, and the need for antiedematous (dexamethasone) medication. Blood samples were taken to analyze the serum concentration of boswellic acids (AKBA and KBA).

Compared with baseline and if measured immediately after the end of radiotherapy and BS/placebo treatment, a reduction of cerebral edema of >75% was found in 60% of patients receiving BS and in 26% of patients receiving placebo (P = .023). These findings may be based on an additional antitumor effect. There were no severe adverse events in either group. In the BS group, 6 patients reported minor gastrointestinal discomfort. BS did not have a significant impact on quality of life or cognitive function. The dexamethasone dose during radiotherapy in both groups was not statistically different. Boswellic acids could be detected in patients' serum.

BS significantly reduced cerebral edema measured by MRI in the study population. BS could potentially be steroid-sparing for patients receiving brain irradiation. Our findings will need to be further validated in larger studies.