title: Linac-based radiosurgery or hypofractionated stereotactic radiotherapy in the treatment of large cerebral arteriovenous malformations.
abstract: OBJECTIVE
  We investigate retrospectively clinical outcome after radiosurgery (RS) or hypofractionated stereotactic radiotherapy (HSRT) in patients with large cerebral arteriovenous malformations (AVMs).
  
  
  METHODS
  This analysis is based on 48 patients with cerebral AVM greater than 4 cm treated with HSRT or RS at our institution. Fifteen patients received HSRT, with 26 Gy median total dose in 4 to 5 fractions, and 33 patients received RS with 17 Gy median total dose in 4 to 5 fractions. Median target volume was 27 cc in HSRT and 7 cc in RS; median maximum diameter was 6 cm and 5 cm, respectively. Seventeen patients experienced intracranial hemorrhage before treatment. Median follow-up was 2.6 years.
  
  
  RESULTS
  The 3-year and 4-year actuarial complete obliteration (CO) after HSRT was 17% and 33% and after RS was 47% and 60%, respectively. Actuarial CO was higher in AVMs less than 5 cm (66% vs. 37% after 4 years). Intracranial hemorrhage after HSRT occurred in 3 of 15 patients after 18 months median, and after RS in 7 of 33 patients after 17 months median. Bleeding risk was significantly higher in patients with prior hemorrhage (p < 0.04). Preexisting neurologic dysfunction improved/dissolved in 50% and remained stable in 45%.
  
  
  CONCLUSIONS
  Large AVMs need a long time period to obliterate and show a high bleeding risk. Multimodal treatment strategies are required to reduce treatment volume before radiotherapy.
authors.affiliation: Department of Radiooncology, University of Heidelberg, Heidelberg, Germany. A.Zabel@dkfz-heidelberg.de
authors.forename: Angelika
authors.initials: A
authors.lastname: Zabel-du Bois
authors.forename: Stefanie
authors.initials: S
authors.lastname: Milker-Zabel
authors.forename: Peter
authors.initials: P
authors.lastname: Huber
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Schlegel
authors.forename: Jürgen
authors.initials: J
authors.lastname: Debus
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D002648:Child; D005260:Female; D006801:Humans; D002538:Intracranial Arteriovenous Malformations / Q000473:pathology / Q000601:surgery*; D020300:Intracranial Hemorrhages / Q000209:etiology; D008297:Male; D008875:Middle Aged; D019106:Postoperative Hemorrhage / Q000209:etiology; D016634:Radiosurgery / Q000009:adverse effects / Q000379:methods*; D011879:Radiotherapy Dosage; D012189:Retrospective Studies; D016896:Treatment Outcome