title: Hypofractionated CyberKnife stereotactic radiosurgery for acoustic neuromas with and without association to neurofibromatosis Type 2.
abstract: CyberKnife stereotactic radiosurgery (CKSRS) has been proved effective in treating intra-cranial lesions. To treat acoustic neuroma (AN) patients with or without neurofibromatosis Type 2 (NF2) associations, the functional preservation of hearing, trigeminal nerve, and facial nerve are important. Twenty-one patients were treated with hypofractionated CKSRS. Fourteen non-NF2 and seven NF2 patients were enrolled. Cranial nerve function, audiograms, and magnetic resonance images (MRI) were monitored. Mean follow-up was 15 month. Tumors with volumes ranging from 0.13 to 24.8 cm3 (mean 5.4 cm3) were irradiated with the marginal dose 1800-2000 cGy/3 fractions. Tumors were treated with an 80 to 89% isodose line (mean 83%) and mean 97.9% tumor coverage. Two patients experienced hearing deterioration (16.7%) in the non-NF2 group, and 3 patients (50%) in the NF2 group. No facial or trigeminal dysfunction, brain stem toxicity, or cerebellar edema occurred. Tumor regression was seen in 9 patients (43%) and stable in 12 patients (57%). 100% tumor control rate was achieved. Hypofractionated CKSRS was not only effective in tumor control but also excellent in hearing preservation for non-NF2 AN. But for NF2 patients, although the tumor control was remarkable, hearing preservation was modest as in non-NF2 patients.
authors.affiliation: National Defense Medical Center, Department of Neurological Surgery, Tri-Service General Hospital, Taipei, Taiwan.
authors.forename: D T
authors.initials: DT
authors.lastname: Ju
authors.forename: J W
authors.initials: JW
authors.lastname: Lin
authors.forename: M S
authors.initials: MS
authors.lastname: Lin
authors.forename: L M
authors.initials: LM
authors.lastname: Lee
authors.forename: H M
authors.initials: HM
authors.lastname: Tseng
authors.forename: C P
authors.initials: CP
authors.lastname: Wei
authors.forename: C H
authors.initials: CH
authors.lastname: Yen
authors.forename: C C
authors.initials: CC
authors.lastname: Hung
authors.forename: K S
authors.initials: KS
authors.lastname: Hung
authors.forename: C M
authors.initials: CM
authors.lastname: Lin
authors.forename: T J
authors.initials: TJ
authors.lastname: Lin
authors.forename: W T
authors.initials: WT
authors.lastname: Chiu
authors.forename: J T
authors.initials: JT
authors.lastname: Tsai
mesh_terms: D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D016518:Neurofibromatosis 2 / Q000150:complications / Q000473:pathology / Q000601:surgery*; D009464:Neuroma, Acoustic / Q000150:complications / Q000473:pathology / Q000601:surgery*; D010525:Peripheral Nerves / Q000503:physiopathology; D016634:Radiosurgery / Q000379:methods*