title: Multisession cyberknife stereotactic radiosurgery of large, benign cranial base tumors: preliminary study.
abstract: OBJECTIVE
  Although radiosurgery plays an important role in managing benign cranial base lesions, the potential for increased toxicity with single-session treatment of large tumors is a concern. In this retrospective study, we report the intermediate-term rate of local control, morbidity, and clinical outcomes of patients with large cranial base tumors treated with multisession stereotactic radiosurgery with the CyberKnife (Accuray, Inc., Sunnyvale, CA).
  
  
  METHODS
  Between 1999 and 2008, 34 consecutive patients with large (>15 cm), benign cranial base tumors (21 meningiomas, 9 schwannomas, 4 glomus jugulare tumors) underwent primary or postoperative radiosurgical treatment using a multisession approach at Stanford University and were considered in this retrospective study. Forty-four percent of these patients had undergone previous subtotal surgical resection or radiotherapy. CyberKnife radiosurgery was delivered in 2 to 5 sessions (median, 3 sessions) to a median tumor volume of 19.3 cm (range, 15.8-69.3 cm). The median marginal dose was 24 Gy (range, 18-25 Gy) prescribed to a median 78% isodose line.
  
  
  RESULTS
  After a median clinical follow-up of 31 months (range, 12-77 months), 21% of patients experienced clinical improvement of neurological symptoms, whereas neurological status remained unchanged among the rest. Four patients experienced prolonged use of glucocorticoids owing to transient neurological worsening and radiographic signs of radiation injury. No permanent neurotoxicity was seen. To date, all tumors remain locally controlled.
  
  
  CONCLUSIONS
  Over our modest length of follow-up, multisession radiosurgery appears to be a safe and effective option for selected large, benign brain and cranial base lesions.
authors.affiliation: Department of Neurosurgery, Stanford University, Stanford, California 94305, USA. tuniz.francesco@gmail.com
authors.forename: Francesco
authors.initials: F
authors.lastname: Tuniz
authors.forename: Scott G
authors.initials: SG
authors.lastname: Soltys
authors.forename: Clara Y
authors.initials: CY
authors.lastname: Choi
authors.forename: Steven D
authors.initials: SD
authors.lastname: Chang
authors.forename: Iris C
authors.initials: IC
authors.lastname: Gibbs
authors.forename: Nancy J
authors.initials: NJ
authors.lastname: Fischbein
authors.forename: John R
authors.initials: JR
authors.lastname: Adler
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D016634:Radiosurgery / Q000009:adverse effects / Q000379:methods*; D012189:Retrospective Studies; D019292:Skull Base Neoplasms / Q000601:surgery*; D016896:Treatment Outcome; D055815:Young Adult