Estimating the Risks of Adverse Radiation Effects After Gamma Knife Radiosurgery for Arteriovenous Malformations

Abstract

Background and Purpose— We evaluated risk factors associated with the development of adverse radiation effects (ARE) after stereotactic radiosurgery (SRS) for cerebral arteriovenous malformations (AVMs). Methods— We evaluated 755 patients with AVM who underwent a single Gamma Knife SRS procedure with at least a 2-year minimum follow-up. Eighty-seven patients (12%) underwent previous resection and 128 (17%) had previous embolization. The median target volume was 3.6 mL (range, 0.1–26.3 mL). The median margin dose was 20 Gy (range, 13–27 Gy). Results— Fifty-five patients (7%) developed symptomatic ARE at a median follow-up of 75 months. The cumulative rates of symptomatic ARE were 3.2%, 5.8%, 6.7%, and 7.5% at 1, 2, 3, and 5 years, respectively. Factors associated with a higher rate of developing symptomatic ARE included larger AVM volume, higher margin dose, larger 12-Gy volume, higher Spetzler–Martin grade, and higher radiosurgery-based score. The rates of developing symptomatic ARE were higher in the brain stem (22%) or thalamus (16%), compared with AVMs located in other brain locations (4%–8%). Nineteen patients (3%) sustained irreversible new neurological deficits related to ARE, and 1 patient died. The rates of irreversible symptomatic ARE were 0.8%, 1.9%, 2.1%, and 2.8% at 1, 2, 3, and 5 years, respectively. The 5-year cumulative rates of irreversible symptomatic ARE were 9.1% in thalamus, 12.1% in brain stem, and 1.4% in other locations. Conclusions— The knowledge of ARE risk rates after AVM radiosurgery can assist informed consent for patients with AVM, their families, and healthcare providers.

Laser interstitial thermal therapy for treatment of cerebral radiation necrosis

“…Although most cases of RN have been described in cases of radiation of brain metastases, RN has also been reported extensively in the neurosurgical literature for gliomas [44][45][46] and arteriovenous malformations [5,47,48]. and likely as peritumoral edema for SRS-treated meningiomas.…”

How to improve obliteration rates during volume-staged stereotactic radiosurgery for large arteriovenous malformations

“…10,11,16 We previously reported that the rates of developing permanent symptomatic AREs in single-session SRS were higher in the brainstem (11%) and thalamus AVMs (7%), compared to AVMs located in other brain locations (0%-3%). 7 In their multicenter study, Cohen-Inbar et al reported that the rate of symptomatic AREs was 14.6% in patients with brainstem AVMs who under-went single-session SRS. 2 The reported rates of symptomatic AREs after VS-SRS has varied between 3% and 7%.…”

High-Flow Vascular Malformations in Children

“…66,67 Obliteration, however, takes several years and patients are at risk for hemorrhage during the latent period. 7,66,68 With higher radiation doses or volumes treated, risks for symptomatic radiation-induced changes increases, 7,68,69 and a greater incidence is reported for AVMs in deeper anatomic locations, such as the brainstem, striatum, or thalamus. 69 With greater nidus volumes (>8-10 cm 3 ), volume-staged radiosurgery may be performed, involving multiple sessions in which roughly 8 to 10 cm 3 of the AVM nidus are treated in each session in 3-to 6-month intervals.…”

“…7,66,68 With higher radiation doses or volumes treated, risks for symptomatic radiation-induced changes increases, 7,68,69 and a greater incidence is reported for AVMs in deeper anatomic locations, such as the brainstem, striatum, or thalamus. 69 With greater nidus volumes (>8-10 cm 3 ), volume-staged radiosurgery may be performed, involving multiple sessions in which roughly 8 to 10 cm 3 of the AVM nidus are treated in each session in 3-to 6-month intervals. [70][71][72] Annual MRIs and catheter angiography at 36 months after treatment are usually obtained to monitor treatment response.…”