Gamma Knife radiosurgery for acoustic schwannoma: effects of low radiation dose and functional prognosis.
The effects of relatively low dose Gamma Knife irradiation on acoustic schwannoma were evaluated in 29 patients followed over 2 years after treatment. The mean dose delivered to the tumor periphery was 12.1 Gy. Lowering of the magnetic resonance signal intensity in the tumor center appeared in 69% and signs of tumor shrinkage appeared in 59% of cases. The cyst in the tumor enlarged in 3 cases, and 2 cases developed hydrocephalus. The percentage of pure-tone hearing preservation was 82% at 3 months, 73% at 6 months, 68% at 12 months. 64% at 18 months and 59% at 24 months in 22 out of 29 cases. Relatively low dose Gamma Knife radiosurgery was effective in suppressing tumor growth, with preservation of hearing.
Hirato
M
M
Department of Neurosurgery, Gunma University School of Medicine, Hidaka Hospital, Maebashi, Japan.
Inoue
H
H
Zama
A
A
Ohye
C
C
Shibazaki
T
T
Andou
Y
Y
D000328:Adult; D000368:Aged; D003390:Cranial Nerve Neoplasms / Q000175:diagnosis / Q000601:surgery*; D004307:Dose-Response Relationship, Radiation; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009464:Neuroma, Acoustic / Q000175:diagnosis / Q000601:surgery*; D011379:Prognosis; D016634:Radiosurgery; D016896:Treatment Outcome