title: Hypofractionated stereotactic radiotherapy for large or involving critical organs cerebral arteriovenous malformations.
abstract: BACKGROUND
  The treatment of large arteriovenous malformations (AVMs) or AVMs involving eloquent regions of the brain remains a challenge. For inoperable lesions, observation, volume-staged radiosurgery or hypofractionated stereotactic radiotherapy (HFSRT) are proposed. The aim of our study was to assess the safety and efficiency of HFSRT for large AVMs located in eloquent areas of the brain.
  
  
  METHODS
  An analysis of records of 49 patients irradiated for cerebral AVMs with a mean dose of 19.9 Gy (12-28 Gy) delivered in 2-4 fractions with planned gap (at least one week) between fractions. Actuarial obliteration rates and annual bleeding hazard were calculated using Kaplan-Meier survival analysis and life tables.
  
  
  RESULTS
  Annual bleeding hazard rates were 4.5% and 1.6% after one and two years of the follow-up, respectively. Actuarial total obliteration rates were 7%, 11%, and 21% and total response rate (total and partial obliterations) 22%, 41%, and 55% after one, two and three years of the follow-up, respectively. There was a trend towards larger total obliteration rate in patients irradiated with fraction dose ≥ 8 Gy and total dose > 21 Gy for lesions of volume ≤ 8.18 cm(3) which was not observed in case of partial obliterations.
  
  
  CONCLUSIONS
  HFSRT results with relatively low obliteration rate but is not associated with a significant risk of permanent neurological deficits if both total and fraction doses are adjusted to size and location of the lesion. Predictive factors for total and partial obliterations can be different; this observation, however, is not firmly supported and requires further studies.
authors: Radiotherapy Department, Maria Skłodowska-Curie Memorial Cancer Center and Institute of Oncology, Gliwice Branch, Gliwice, Poland.
authors: Sławomir
authors: S
authors: Blamek
authors: Dawid
authors: D
authors: Larysz
authors: Leszek
authors: L
authors: Miszczyk
authors: Adam
authors: A
authors: Idasiak
authors: Adam
authors: A
authors: Rudnik
authors: Rafał
authors: R
authors: Tarnawski
keywords: arteriovenous malformations; hemorrhage; hypofractionated stereotactic radiotherapy; obliteration; stereotactic radiosurgery