Efficacy of Short-Course Bevacizumab for Brain Tumor Radiation Necrosis with a Volumetric Analysis

Radiation necrosis (RN) is a challenging complication of cranial irradiation, often requiring corticosteroids for management. This study evaluates the clinical and radiologic efficacy of a short-course bevacizumab (BEV) regimen for brain tumor RN, with a volumetric assessment.

We retrospectively analyzed 11 patients with magnetic resonance imaging-confirmed RN who received 2 or 3 cycles of BEV (7.5 mg/kg every 3 weeks). Volume changes of nonenhancing RN, enhancing RN, perilesional edema, and total lesion (RN + edema) were quantified at 4 time points (pretreatment, start, end, and post-treatment) using artificial intelligence-assisted volumetric analysis (DeepBratumIA). Clinical outcomes were assessed using Eastern Cooperative Oncology Group performance status and changes in corticosteroid use.

Clinical improvement or stabilization was observed in 91% of patients, with steroid use decreasing from 91% at baseline to 36% at treatment completion. Median enhancing RN volume significantly decreased from 5.1 cm³-1.2 cm³ (P = 0.031), while nonenhancing RN volume showed a nonsignificant change (2.3 cm³-2.0 cm³, P = 0.414). Perilesional edema volume markedly declined from 65 cm³-18 cm³ (P = 0.001), and total lesion volume decreased from 69 cm³-21 cm³ (P = 0.001). No statistically significant differences were observed between steroid-maintained and steroid-discontinued groups in the magnitude of volume change at any time point. Partial volumetric rebound occurred post-treatment, but most patients maintained clinical benefit.

This study suggests the clinical and radiologic efficacy of short-course BEV as a practical steroid-sparing strategy for RN management.