Brain Arteriovenous Malformations Treated With Linear Accelerator-Based Stereotactic Radiosurgery: A...

Background Stereotactic radiosurgery (SRS) is an established treatment option for selected patients with brain arteriovenous malformations (bAVMs), particularly for lesions not amenable to microsurgical resection or located in surgically high-risk areas. SRS can be delivered through different platforms, including Gamma Knife, CyberKnife, and linear accelerator (LINAC)-based systems. This retrospective single-institution study evaluated outcomes of patients with bAVMs treated with LINAC-based SRS at a quaternary care center in Bogotá, Colombia. Materials and methods We conducted a retrospective observational study of patients with bAVMs treated with LINAC-based SRS guided by triple-fusion imaging between 2011 and 2017. Clinical, treatment, and imaging data were collected from medical records. Telephone interviews were used only to supplement clinical follow-up and were not used to determine radiological obliteration. The primary outcome was radiological obliteration during the available follow-up period, assessed by follow-up imaging. Actuarial obliteration rates were estimated using Kaplan-Meier analysis and interpreted as exploratory because of limited follow-up and censoring. Univariable Cox proportional hazards analyses were performed as exploratory analyses to evaluate factors associated with obliteration. Results Eighty-two patients were included. At presentation, 36 patients (44.0%) had ruptured bAVMs, 61 (74.4%) had lesions in eloquent areas, and most had Spetzler-Martin grade III malformations. Prior embolization was performed in 47 patients (57.3%). Complete radiological obliteration was documented in 27 patients (33.0%) during available follow-up. The median follow-up was 16.3 months, and 46 patients (56.1%) were lost to follow-up before completing three years of institutional follow-up. Actuarial obliteration estimates at later time points should therefore be interpreted cautiously. In exploratory univariable Cox analysis, radiosurgery dose >20 Gy was associated with a shorter time to obliteration. Conclusions This single-institution retrospective study describes radiological and clinical outcomes after LINAC-based SRS for bAVMs in a Latin American quaternary care center. The findings suggest that LINAC-based SRS is a feasible treatment approach when appropriate technology, planning expertise, and quality assurance are available. However, the short median follow-up, substantial loss to follow-up, and lack of a comparator group limit conclusions regarding effectiveness. Future prospective studies with standardized long-term imaging follow-up are needed.