Main Session
Sep
27
PQA 01 - Gastrointestinal Cancer and Central Nervous System
Presenter(s)
Andrew Simpson, MD - UAB Radiation Oncology, Birmingham, AL
A. Simpson1, G. H. Tsemo2, J. H. Johnston2, and M. C. Dobelbower3; 1University of Alabama at Birmingham, Birmingham, AL, 2University of Birmingham at Alabama, Birmingham, AL, 3University of Alabama at Birmingham Department of Radiation Oncology, Birmingham, AL
Purpose/Objective(s):
Arteriovenous malformations (AVMs) are connections between arteries and veins causing abnormal blood flow with a risk of rupture. Here, we detail an interim analysis of a single institution cohort of pediatric patients treated with linear accelerator stereotactic radiosurgery (LINAC-SRS) and a hypothesis that obliteration rates are comparable to adults. We also evaluated treatment tolerance as a function of objective imaging findings and queryable neurologic symptoms after treatment and resolution.Materials/Methods:
Patients were treated with LINAC-SRS at a single institution from July 2013 to December 2025. Treatment was performed using VMAT planning with a frameless linear accelerator setup and non-coplanar arcs. Patients received a marginal dose of 17.5 Gy and treatment was delivered in a single fraction. Obliteration status was analyzed for all patients with 3 years of followup, and treatment tolerance was analyzed for all patients receiving LINAC-SRS. Obliteration was confirmed with CTA. Treatment tolerance was evaluated as post-treatment hemorrhage or edema on imaging and queryable neurologic deficits. Neurologic deficits were recorded categorically as hemiparesis, cranial nerve deficits, brainstem dysfunction, or other and whether or not they resolved.Results:
34 patients were identified with 1 excluded from obliteration analysis for receiving Gamma Knife and 14 for not having at least 3 years of followup. Median follow-up for 19 patients included in obliteration analysis 3 years after treatment was 38 months. The obliteration rate was 84.2% with 4 patients requiring a second procedure to acheive obliteration. Of the 33 patients evaluated for treatment tolerance after LINAC-SRS, no patients suffered a hemorrhagic event within one year of treatment and 32.4% were found to have some degree of post-treatment edema on MRI. Neurologic deficits as specified above were found in 11.8% of patients, with all of them resolving on further followup. One patient that failed to acheive obliteration after 2 courses of LINAC-SRS suffered a rupture that resulted in death.Conclusion:
This interim analysis of pediatric patients treated with LINAC-SRS suggests that it is an effective and well-tolerated treatment in this population. With 38 months of median follow-up, obliteration rates rival those seen in the adult population. Treatment was also well tolerated, with no unresolved neurologic deficits on follow-up and low rates of edema. This highlights the utility of LINAC-SRS in a sensitive population where minimizing long term adverse effects is paramount.