# Stereotactic radiosurgery for cerebral arteriovenous malformations: Evaluation of long-term outcomes in a single institute cohort

## TL;DR

This study evaluates the long-term effectiveness of LINAC-based stereotactic radiosurgery for cerebral AVMs, showing high obliteration rates and low rebleeding risks.

## Contribution

The study provides new insights into the long-term outcomes of LINAC-based SRS for AVMs, including obliteration rates and factors influencing treatment success.

## Key findings

- 5-year obliteration rates were 85.2% for grades I–II and 62.1% for grades IV–V.
- Annual cumulative bleeding rates post-SRS were 1.5% in the first year and 0.7% in the second year.
- Prior embolization did not affect obliteration rates, and no radiation necrosis was observed.

## Abstract

The study we describe focuses on evaluating the effectiveness of linear accelerator (LINAC) stereotactic radiosurgery (SRS) in the treatment of cerebral arteriovenous malformations (AVMs). This treatment option is gaining interest due to the uncertainties associated with combined radiosurgical and endovascular treatments and the significant technological advancements in SRS. The primary goals of the study are to assess rates of obliteration (successful closure of the AVM) and rebleeding (the recurrence of bleeding posttreatment), as well as to identify factors influencing obliteration rates and to document any adverse effects associated with the procedure.

The study retrospectively analyzed data from 134 patients treated with LINAC-based SRS for cerebral AVMs. The patients were categorized based on their prior treatments: 50 had undergone partial embolization, 8 had received a combination of embolization and surgery and 1 patient had a surgical intervention. Furthermore, 75 patients had received no prior treatment. Kaplan–Meier survival analysis and log-rank tests were employed to calculate actuarial obliteration rates and annual cumulative bleeding rates following SRS treatment.

The study found that obliteration rates after SRS treatment increased over time, with 5‑year obliteration rates of 85.2% for grades I–II, 76.4% for grade III, and 62.1% for grades IV–V. Annual cumulative bleeding rates post-SRS were 1.5% for the first year and 0.7% for the second year. Interestingly, prior embolization did not affect the obliteration rate. The median time to obliteration was 36 months (range 7–162 months). Obliteration rates were significantly better in Spetzler–Martin (SM) grade I–II (85% at 5 years) compared to grade III–V (68% at 5 years, p = 0.01). Age, sex, and pediatric status had no statistically significant influence on AVM response to SRS. No radiation necrosis was observed in our cohort.

This study contributes to the body of evidence supporting the effectiveness of SRS in treating cerebral AVMs and provides valuable insights into factors affecting treatment outcomes. The findings suggest that patients can expect a high chance of successful obliteration of the AVM with minimal adverse effects, making SRS a compelling option for those affected by this condition.