Efficacy and safety of low-dose vs medium-dose bevacizumab for radiation-induced brain necrosis in nasopharyngeal carcinoma survivors

Background and Purpose Previous studies had found that bevacizumab could alleviate the brain edema and symptoms in patients with radiation-induced brain necrosis (RN) after radiotherapy for nasopharyngeal carcinoma (NPC). However, evidence concerning the optimal dose of bevacizumab for RN remained insufficient.Methods We consecutively included NPC patients who were newly diagnosed with RN, treated with bevacizumab and followed up for 6 months from the study NCT 03908502. The primary outcome was the 8-week response rate, defined as ≥25% edema reduction in MRI plus no worsening of Late Effects of Normal Tissues (LENT)/Subjective, Objective, management, Analytic (SOMA) scores. The secondary outcomes included 8-week changes of the (LENT)/SOMA) scale grade, cognitive function, quality of life, RN recurrence rate, and the incidence of adverse events. The propensity score matching analyses (PSM) was conducted for the sensitivity analysis.Results A total of 195 eligible patients were included. The response rate did not differ significantly between the conventional medium-dose (5 mg/kg) and low-dose (2.5 mg/kg) bevacizumab group (73.6% vs 84.8%, adjusted OR 3.06, 95% CI 0.89–10.52, p = 0.077). Neither group showed a significant difference in LENT/SOMA grade improved rate, QOL score improved rate, MoCA score improved rate, and RN recurrence rate. The adverse events were less common in the low-dose group than in the medium-dose group (55.8% vs 21.2%, adjusted OR 0.22, 95% CI 0.09–0.54, p = 0.001). Similar results were yield after PSM.Conclusion Our results showed that there was no significant difference of the efficiency between the low-dose bevacizumab and conventional medium-dose bevacizumab for RN patients after NPC. In addition, the adverse events were less common in low-dose group.