title: Evaluation of Dose-Staged Gamma Knife Radiosurgical Treatment Method for High-Risk Brain Metastases.
abstract: OBJECTIVE
  The study aim was to evaluate the utility of 2-fraction, dose-staged Gamma Knife radiosurgery (GKRS) in patients with large, high-risk brain metastases (BMs).
  
  
  METHODS
  A total of 63 large BMs in eloquent areas in 61 patients were treated with GKRS in 2 reduced doses. Treatment planning was conducted on the 50% isodose line and included the whole tumor volume as seen on T1 contrast-enhanced and T2-weighted magnetic resonance imaging sections. The median margin and central dose were 12 Gy and 24 Gy, respectively, for both fractions. Patients were assessed using the Graded Prognostic Assessment, Recursive Partitioning Analysis, and Score Index for Radiosurgery.
  
  
  RESULTS
  Thirty-two patients (53%) had been diagnosed with multiple BMs, and extracranial metastases were present in a majority of patients before GKRS treatment. Significant decreases in tumor volume were observed between the first and second treatment stages. At 3-month follow-up, a majority of patients presented with stable or decreased lesion volumes. The remaining patients showed intralesional hemorrhaging or increasing edema that was managed conservatively. Three patients were diagnosed with tumor progression at the last follow-up and received microsurgical treatment. The median time to radiologic progression was 7 months. The median survival time after initial BM diagnosis was 6 months. Survival times were significantly longer than 3 of 4 calculated prognostic survival estimates.
  
  
  CONCLUSIONS
  The new 2-fraction, dose-staged GKRS concept seems to be a well-tolerated and effective treatment option for large BMs. This method may be indicated in elderly patients or patients with surgical contraindications with large or high-risk brain metastases.
authors.affiliation: Department of Neurosurgery, Medical University Vienna, Vienna, Austria.
authors.forename: Josa M
authors.initials: JM
authors.lastname: Frischer
authors.affiliation: Department of Neurosurgery, Medical University Vienna, Vienna, Austria.
authors.forename: Astrid
authors.initials: A
authors.lastname: Fraller
authors.affiliation: Department of Radiology, Medical University Vienna, Vienna, Austria.
authors.forename: Ammar
authors.initials: A
authors.lastname: Mallouhi
authors.affiliation: St. Josef Hospital Vienna, Internal Medicine I/Oncology, Vienna, Austria.
authors.forename: Ursula M
authors.initials: UM
authors.lastname: Vogl
authors.affiliation: Department of Radiation Therapy, Medical University Vienna, Vienna, Austria.
authors.forename: Franziska
authors.initials: F
authors.lastname: Baier
authors.affiliation: Department of Neurosurgery, Medical University Vienna, Vienna, Austria.
authors.forename: Adolf
authors.initials: A
authors.lastname: Ertl
authors.affiliation: Department of Internal Medicine I & Comprehensive Cancer Center Central Nervous System Unit, Medical University Vienna, Vienna, Austria.
authors.forename: Matthias
authors.initials: M
authors.lastname: Preusser
authors.affiliation: Department of Neurosurgery, Medical University Vienna, Vienna, Austria.
authors.forename: Engelbert
authors.initials: E
authors.lastname: Knosp
authors.affiliation: Department of Neurosurgery, Medical University Vienna, Vienna, Austria.
authors.forename: Klaus
authors.initials: K
authors.lastname: Kitz
authors.affiliation: Department of Neurosurgery, Medical University Vienna, Vienna, Austria. Electronic address: brigitte.gatterbauer@meduniwien.ac.at.
authors.forename: Brigitte
authors.initials: B
authors.lastname: Gatterbauer
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001317:Austria / Q000453:epidemiology; D001929:Brain Edema / Q000401:mortality / Q000517:prevention & control; D001932:Brain Neoplasms / Q000401:mortality / Q000532:radiotherapy* / Q000556:secondary*; D002543:Cerebral Hemorrhage / Q000401:mortality / Q000517:prevention & control; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000401:mortality* / Q000517:prevention & control; D015995:Prevalence; D000069473:Radiation Dose Hypofractionation; D011832:Radiation Injuries / Q000401:mortality* / Q000517:prevention & control; D016634:Radiosurgery / Q000401:mortality* / Q000706:statistics & numerical data; D011879:Radiotherapy Dosage; D012189:Retrospective Studies; D012307:Risk Factors; D015996:Survival Rate; D016896:Treatment Outcome
keywords: Brain metastases; Dose-staged Gamma Knife radiosurgery; Radionecrosis