Outcome Evaluation of Repeat Stereotactic Radiosurgery for Cerebral Arteriovenous Malformations

Abstract

Background: Repeat stereotactic radiosurgery (SRS) for persistent cerebral arteriovenous malformation (AVM) has generally favorable patient outcomes. However, reporting studies are limited by small patient numbers and single-institution biases. The purpose of this study was to provide the combined experience of multiple centers, in an effort to fully define the role of repeat SRS for patients with arteriovenous malformation. Methods: This multicenter, retrospective cohort study included patients treated with repeat, single-fraction SRS between 1987 and 2022. Follow-up began at repeat SRS. The primary outcome was a favorable patient outcome, defined as a composite of nidus obliteration in the absence of hemorrhage or radiation-induced neurological deterioration. Secondary outcomes were obliteration, hemorrhage risk, and symptomatic radiation-induced changes. Competing risk analysis was performed to compute yearly rates and identify predictors for each outcome. Results: The cohort comprised 505 patients (254 [50.3%] males; median [interquartile range] age, 34 [15] years) from 14 centers. The median clinical and magnetic resonance imaging follow-up was 52 (interquartile range, 61) and 47 (interquartile range, 52) months, respectively. At last follow-up, favorable outcome was achieved by 268 (53.1%) patients (5-year probability, 50% [95% CI, 45%–55%]) and obliteration by 300 (59.4%) patients (5-year probability, 56% [95% CI, 51%–61%]). Twenty-eight patients (5.6%) experienced post-SRS hemorrhage with an annual incidence rate of 1.38 per 100 patient-years. Symptomatic radiation-induced changes were evident in 28 (5.6%) patients, with most occurring in the first 3 years. Larger nidus volumes (between 2 and 4 cm 3 , subdistribution hazard, 0.61 [95% CI, 0.44–0.86]; P =0.005; >4 cm 3 , subdistribution hazard, 0.47 [95% CI, 0.32–0.7]; P <0.001) and brainstem/basal ganglia involvement (subdistribution hazard, 0.6 [95% CI, 0.45–0.81]; P <0.001) were associated with reduced probability of favorable outcome. Conclusions: Repeat SRS confers reasonable obliteration rates with a low complication risk. With most complications occurring in the first 3 years, extending the latency period to 5 years generally increases the rate of favorable patient outcomes and reduces the necessity of a third intervention.

Stereotactic radiosurgery for brain arteriovenous malformations in patients with hereditary hemorrhagic telangiectasia

“…AVM obliteration was confirmed on MRI when there was a lack of abnormal flow voids or absence of arteriovenous shunting on cerebral DSA. [ 22 ] MRI-documented obliteration cases were included due to the reluctance of patients to undergo repeated DSA procedures; the incidence of DSA-related neurological complications is not inconsequential and brain MRI is highly sensitive in identifying AVM obliteration. [ 22 ] Radiation-induced changes (RIC) were defined as T2-weighted or fluid-attenuated inversion recovery perinidal hyperintensities being further classified as asymptomatic or symptomatic.…”

“…[ 22 ] MRI-documented obliteration cases were included due to the reluctance of patients to undergo repeated DSA procedures; the incidence of DSA-related neurological complications is not inconsequential and brain MRI is highly sensitive in identifying AVM obliteration. [ 22 ] Radiation-induced changes (RIC) were defined as T2-weighted or fluid-attenuated inversion recovery perinidal hyperintensities being further classified as asymptomatic or symptomatic. [ 39 ] We assessed the mortality of the sample and neurological outcome at the last follow-up by mRS (modified Rankin Scale).…”

Third Stereotactic Radiosurgery for Residual Arteriovenous Malformations: A Retrospective Multicenter Study

“…Delayed cyst formation was identified in 4.2% of the patients at a median time of 23 months. 8 In the study by the Pittsburgh group on repeat SRS, symptomatic adverse radiation effects manifesting as homonymous hemianopsia occurred in 1 of the 12 patients who underwent third FIGURE 2. Illustrative case of a 15-year-old boy treated with GKRS for a ruptured, left Sylvian fissure arteriovenous malformation.…”

“…The 3-year and 5-year cumulative probability rates of AVM hemorrhage after repeat SRS were 3.2% and 3.9%, respectively. 8 Given that the hemorrhage risk in the latency period was low and that most symptomatic RIC occurred during the first 3 years after the second SRS, the authors suggested extending the latency period to 5 years so as to allow more patients to achieve a favorable outcome. 8…”