Linear Accelerator (LINAC) Radiosurgical Management of Brain Arteriovenous Malformations: An Experience From a Tertiary Care Center.

INTRODUCTION

Brain arteriovenous malformations (AVM) are complex vascular pathologies with a significant risk of hemorrhage. Stereotactic radiosurgery (SRS) is an effective treatment modality for AVM, initially popularized on the Gamma Knife (Elekta AB, Stockholm, Sweden) platform, and now benefits from the modern advances in linear accelerator (LINAC)-based platforms. This study evaluates the outcomes of LINAC-based SRS/hypofractionated stereotactic radiotherapy (hFSRT) for cerebral AVMs.

MATERIALS AND METHODS

Between December 2018 and April 2024, 15 patients with cerebral AVMs underwent SRS/hFSRT at a tertiary government hospital. Patient selection was based on AVM size, location, surgical unsuitability, and patient preference. All patients underwent MRI and cerebral angiography for nidus delineation. SRS was planned using Monaco TPS (treatment planning system) (Elekta AB, Stockholm, Sweden) with VMAT (volumetric modulated arc therapy) technique, delivering a median dose of 20 Gy in single fractions for small AVMs and 28 Gy in four fractions for large AVMs. Patients were followed up with annual MRI and angiography to assess obliteration.

RESULTS

The cohort had a median age of 22 years, with a median nidus volume of 3.76 cc. The crude obliteration rate was 60%, confirmed by MRI/angiography. Actuarial obliteration rates at two, three, and five years were 65.71%, 73.57%, and 77.14%, respectively. Smaller AVMs (<3 cc) and those with a modified AVM radiosurgery score <1.5 had nearly 100% obliteration rates. Large AVMs (>10 cc) treated with hypofractionated SRT showed partial responses only. Significant predictors of obliteration included prescription dose, AVM volume, and modified AVM radiosurgery score.

CONCLUSION

LINAC-based SRS demonstrates comparable efficacy to other modalities for treating cerebral AVMs, with obliteration rates influenced by dose, AVM volume, and pre-treatment radiosurgery score. Larger AVMs pose a greater challenge, suggesting a need for adjunctive treatments or higher fractionated doses to improve outcomes.