Boron neutron capture therapy plus bevacizumab versus bevacizumab alone in recurrent glioblastoma: a propensity score–matched analysis

Background Boron neutron capture therapy (BNCT) presents a targeted re-irradiation strategy for recurrent glioblastoma. However, its survival benefit remains unclear, as few studies have compared the addition of BNCT to bevacizumab (BEV) with BEV alone or other salvage approaches. Methods We retrospectively analyzed 171 adults with recurrent glioblastoma: 116 treated with bevacizumab ± chemotherapy (control group) and 55 treated with BNCT plus bevacizumab ± chemotherapy (BNCT group). To improve comparability, propensity score matching was performed using age, performance status, recurrent tumor volume, recurrence-to-salvage-treatment interval, the number of relapses, re-resection, and chemotherapy use. Survival outcomes were assessed using Kaplan–Meier estimates and Cox proportional hazards models. Results In the matched cohort (n = 98), progression-free survival (PFS) was significantly longer in the BNCT group compared with the control group (median 5.34 vs 3.70 months, Hazard ratio [HR]: 0.54, P = 0.026), while overall survival (OS) was comparable (HR: 0.86, P = 0.524). The objective response rate was significantly higher in the BNCT group compared to the control group (67.4% vs. 47.0%; P = 0.041). Multivariable analysis showed that absence of callosal involvement (Odds ratio [OR]: 0.10, P = 0.033) and higher minimum absorbed dose (OR: 1.09; P = 0.028) were independently associated with better BNCT response. Conclusions BNCT plus bevacizumab was associated with higher objective response rate and improved PFS compared with bevacizumab alone in patients with recurrent glioblastoma, although no OS difference was demonstrated. These findings support BNCT as a salvage strategy but warrant prospective validation.