title: Radiotherapeutic management of vestibular schwannomas using size- and location-adapted fractionation regimens to maximize the therapeutic ratio.
abstract: BACKGROUND
  We evaluated and compared the radiographic and clinical outcomes of patients with vestibular schwannomas treated with single fraction stereotactic radiosurgery (SRS), 5 fractions of hypofractionated stereotactic radiation therapy (hSRT), or 25 to 30 fractions of conventionally fractionated stereotactic radiation therapy (cfSRT).
  
  
  METHODS
  Fifty-six patients treated with LINAC-based SRS (median, 12.5 Gy), hSRT (25 Gy), or cfSRT (median, 54 Gy) were retrospectively reviewed. Fractionation was based on the size of the tumor, proximity to the brainstem, and potential risk of neurological sequelae. Median follow-up time was 55.2 months.
  
  
  RESULTS
  The pretreatment median tumor diameter was significantly smaller for SRS (1.14 cm) compared with hSRT (1.7 cm) (P = .03) and cfSRT (2.0 cm) (P < .001). The overall local tumor control was 96.4%: 100% SRS, 100% hSRT, and 90% cfSRT (P = .19). Tumor regression was observed in 53.3% of SRS, 76.2% of hSRT, and 90% of cfSRT (P = .05). There was less transient expansion of tumors treated with cfSRT (5%) than with SRS (53.3%) or hSRT (28.6%) (P = .005). The median time to regression was 13.8 months for SRS, 14.2 months for hSRT, and 5.5 months for cfSRT (P = .34). There was a 3.6% incidence of grade 3 trigeminal neuropathy, but there was no grade 3 facial neuropathy.
  
  
  CONCLUSIONS
  All 3 regimens demonstrated similar excellent local control with minimal toxicity; however, the ability of hSRT to treat larger tumors with comparable outcomes to SRS and greater patient convenience when compared with cfSRT suggest that hSRT may offer the optimal treatment approach.
authors.affiliation: Cancer Treatment Centers of America, Goodyear, Arizona.
authors.forename: Benjamin G
authors.initials: BG
authors.lastname: Slane
authors.affiliation: University of Arizona, Department of Radiation Oncology, Tucson, Arizona. Electronic address: ugoyal@email.arizona.edu.
authors.forename: Uma
authors.initials: U
authors.lastname: Goyal
authors.affiliation: University of Arizona, Department of Radiation Oncology, Tucson, Arizona.
authors.forename: Joel L
authors.initials: JL
authors.lastname: Grow
authors.affiliation: University of Arizona, Department of Radiation Oncology, Tucson, Arizona.
authors.forename: Christopher
authors.initials: C
authors.lastname: Morrison
authors.affiliation: University of Wisconsin, Department of Radiation Oncology, Madison, Wisconsin.
authors.forename: Craig R
authors.initials: CR
authors.lastname: Hullett
authors.affiliation: Intermountain Healthcare, Salt Lake City, Utah.
authors.forename: John
authors.initials: J
authors.lastname: Gordon
authors.affiliation: University of Arizona, Department of Radiation Oncology, Tucson, Arizona.
authors.forename: Abhay
authors.initials: A
authors.lastname: Sanan
authors.affiliation: University of Arizona, Department of Radiation Oncology, Tucson, Arizona.
authors.forename: Baldassarre
authors.initials: B
authors.lastname: Stea
mesh_terms: D000328:Adult; D000368:Aged; D001921:Brain / Q000000981:diagnostic imaging; D019583:Dose Fractionation, Radiation; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009464:Neuroma, Acoustic / Q000000981:diagnostic imaging / Q000473:pathology / Q000532:radiotherapy*; D000069473:Radiation Dose Hypofractionation; D011832:Radiation Injuries / Q000188:drug therapy / Q000209:etiology; D016634:Radiosurgery / Q000009:adverse effects*; D016896:Treatment Outcome