Radiation schedules in relation to obliteration and complications in hypofractionated conformal stereotactic radiotherapy of arteriovenous malformations.
OBJECTIVE
The purpose of this investigation was to assess the obliteration rate and complications following different radiation schedules of hypofractionated conformal stereotactic radiotherapy for cerebral arteriovenous malformations (AVMs).


METHODS
Twenty-five patients were treated with 35 Gy in 5 fractions, whereas 31 patients were treated with 30-32.5 Gy (mean: 31.6 +/- 0.23 Gy) in 5 fractions. A complete angiographic follow-up is available for 40 patients.


RESULTS
Thirty-seven out of 40 patients (92.5%) have so far shown obliteration of their AVMs after a mean time of 3.2 +/- 0.26 years (range: 2-8 years). The mean AVM volume in these patients was 8.2 +/- 1.0 cm(3) (range: 1.5-29 cm(3)). There was a higher rate of obliteration (88%) in patients treated with 35 Gy compared to those treated with < 35 Gy (78%), even if this was not statistically significant. There was a significantly shorter time to obliteration in patients treated with 35 Gy. All patients who experienced symptomatic radionecrosis belonged to the group treated with 35 Gy.


CONCLUSIONS
A radiation schedule of 35 Gy in 5 fractions may be more effective than a radiation schedule of <35 (30-32.5) Gy in obliterating AVMs. This may, however, be at the price of an increased risk of symptomatic radionecrosis.
Lindvall
Peter
P
Department of Neurosurgery, Umeå University Hospital, Umeå, Sweden. peter_lindvall_nkk @ hotmail.com
Bergström
Per
P
Blomquist
Michael
M
Bergenheim
A Tommy
AT
D000293:Adolescent; D000328:Adult; D000368:Aged; D001921:Brain / Q000473:pathology / Q000528:radiation effects*; D002533:Cerebral Angiography; D016009:Chi-Square Distribution; D004307:Dose-Response Relationship, Radiation; D005260:Female; D006801:Humans; D002538:Intracranial Arteriovenous Malformations / Q000601:surgery*; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D009336:Necrosis / Q000209:etiology; D011832:Radiation Injuries / Q000473:pathology; D016634:Radiosurgery / Q000009:adverse effects*; D016896:Treatment Outcome