Treatment of giant cerebral arteriovenous malformation: hypofractionated stereotactic radiation as the first stage.
BACKGROUND
Treatment of giant cerebral arteriovenous malformations (AVMs) remains a challenge.


OBJECTIVE
To propose hypofractionated stereotactic radiotherapy (HSRT) as a part of staged treatment, and evaluate its effect by analyzing AVM volume changes.


METHODS
From 2001 to 2007, 20 AVMs larger than 5 cm were treated by HSRT and followed up using magnetic resonance imaging. Patients' median age was 34 years (8-61 years). Eleven patients presented with hemorrhage and 9 with seizure. Ten patients had previous embolization and radiosurgery had failed in 4. Thirteen AVMs (65%) were classified as Spetzler-Martin grade V and 7 as grade IV. Median pretreatment volume was 46.84 cm³ (12.51-155.38 cm³). Dose was 25 to 30 Gy in 5 to 6 daily fractions. Median follow-up was 32 months.


RESULTS
Median AVM volume decreased to 13.51 cm³ (range, 0.55-147.14 cm³). Residual volume varied from 1.5% to 98%. Volume decreased 44% every year on average. We noted that 6-Gy fractions were more effective (P = .040); embolized AVM tended to respond less (P = .085). After HSRT, we reirradiated 4 AVMs, with 3 amenable to single dose and one with fractions. After HSRT, one patient had an ischemic stroke and one had increased seizure frequency. One AVM bled during follow-up (2.06%/year). No complete obliteration was confirmed.


CONCLUSIONS
HSRT can turn some giant AVMs manageable for single-dose radiosurgery. Six-Gray fractions were better than 5-Gy and routine embolization seemed unhelpful. There was no increase in bleeding risk with this approach. Future studies with longer follow-up are necessary to confirm our observation.
Division of Neurosurgery, David Geffen School of Medicine, University of California, Los Angeles, California, USA.
Furen
F
Xiao
Alessandra A
AA
Gorgulho
Chun-Shu
CS
Lin
Chien-Hua
CH
Chen
Nzhde
N
Agazaryan
Fernado
F
Viñuela
Michael T
MT
Selch
Antonio A F
AA
De Salles
D000293:Adolescent; D000328:Adult; D002543:Cerebral Hemorrhage / Q000209:etiology* / Q000517:prevention & control*; D002648:Child; D019583:Dose Fractionation, Radiation; D005260:Female; D006801:Humans; D002538:Intracranial Arteriovenous Malformations / Q000150:complications* / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D016634:Radiosurgery / Q000009:adverse effects / Q000379:methods*; D011879:Radiotherapy Dosage; D016896:Treatment Outcome; D055815:Young Adult