Main Session
Sep 28
PQA 04 - Breast Cancer, Patient Reported Outcomes/QoL/Survivorship, Functional Radiation Medicine, Hematologic Malignancies, Palliative Care, and International/Global Oncology

2926 - Long-Term Complete Obliteration Rates after LINAC-Based Stereotactic Radiosurgery for Arteriovenous Malformations: A Retrospective Analysis

03:00pm - 04:00pm ET
Poster Hall - Exhibit Hall A
Screen: 12
POSTER

Presenter(s)

Sue Yi, MD, PhD Headshot
Sue Yi, MD, PhD - University of Wisconsin-Madison, Madison, WI

S. Yi1, H. Menon1, T. Kruser2, Z. E. Labby1, R. A. B. Bayliss1, W. A. Tome3, D. Jacqmin4, A. C. Arnold1, P. M. Hill4, A. S. Ahmed5, D. Niemann5, B. Aagaard-Kienitz5, R. J. Demsey5, S. P. Howard1, and B. A. Morris1; 1Department of Human Oncology, University of Wisconsin Hospitals and Clinics, Madison, WI, 2SSM Health Dean Medical Group, Turville Bay Radiation Oncology Center, Madison, WI, 3Department of Radiation Oncology, Montefiore Einstein Comprehensive Cancer Center, Bronx, NY, 4Department of Human Oncology, University of Wisconsin–Madison, Madison, WI, 5Department of Neurological Surgery, University of Wisconsin Hospital and Clinics, Madison, WI

Purpose/Objective(s): Stereotactic radiosurgery (SRS) is an established treatment for intracranial arteriovenous malformations (AVMs), yet long-term obliteration rates and durability remain incompletely characterized. Here, we present the long-term clinical outcomes of LINAC-based SRS treatments at a high-volume single institution academic center.

Materials/Methods: We retrospectively reviewed consecutive patients with AVMs treated with LINAC-based SRS between 1989 and 2023. Clinical, radiographic, and dosimetric data were collected. The primary endpoint was complete obliteration (CO). Kaplan-Meier analysis was used to estimate time to CO. Multivariable logistic regression was performed to identify prognostics indicators of AVM obliteration.

Results: A total of 140 patients were identified; 133 were evaluable for response. Complete obliteration occurred in 70 patients (52.6%), partial response in 48 (36.1%), stable disease in 11 (8.3%), and progression in 4 (3.0%). The actuarial probability of complete obliteration at 10 years was 56.5% (95% CI, 47–68%). Median Kaplan Meier estimate of time to obliteration was 13.2 years. Among patients who did not achieve obliteration (n=63), median imaging follow-up was 7.2 years. Post-SRS hemorrhage occurred in 19 patients (14%), with a median time to bleed of 30 months. On multivariable analysis, lower Spetzler-Martin grade (p=0.038) and higher prescription dose (p=0.034) were independently associated with complete obliteration, whereas target volume was not (p=0.079).

Conclusion: LINAC-based SRS provides durable long-term obliteration for AVMs with acceptable hemorrhage risk. Spetzler-Martin grade and treatment dose independently predict treatment success. These findings support dose optimization and risk stratification to improve long-term outcomes following SRS.