Stereotactic radiotherapy for intracranial nonacoustic schwannomas including facial nerve schwannoma.
OBJECTIVE
Although the effectiveness of stereotactic radiosurgery for nonacoustic schwannomas is currently being assessed, there have been few studies on the efficacy of stereotactic radiotherapy (SRT) for these tumors. We investigated the long-term outcome of SRT for nonacoustic intracranial nerve schwannomas.


METHODS
Seventeen patients were treated between July 1994 and December 2006. Of these patients, 7 had schwannomas located in the jugular foramen, 5 in the trigeminal nerve, 4 in the facial nerve, and 1 in the oculomotor nerve. Radiotherapy was used as an initial treatment without surgery in 10 patients (59%) and after initial subtotal resection in the remaining patients. The tumor volume ranged from 0.3 to 31.3 mL (mean, 8.2 mL). The treatment dose was 40 to 54 Gy in 20 to 26 fractions. The median follow-up period was 59.5 months (range, 7.4-122.6 months). Local control was defined as stable or decreased tumor size on follow-up magnetic resonance imaging.


RESULTS
Tumor size was decreased in 3 patients, stable in 13, and increased in 1 after SRT. Regarding neurologic symptoms, 8 patients (47%) had improvement and 9 patients were unchanged. One patient had an increase in tumor size and received microsurgical resection at 32 months after irradiation. No patient had worsening of pre-existing neurologic symptoms or development of new cranial nerve deficits at the last follow-up.


CONCLUSIONS
SRT is an effective alternative to surgical resection for patients with nonacoustic intracranial nerve schwannomas with respect to not only long-term local tumor control but also neuro-functional preservation.
Nishioka
Kentaro
K
Department of Radiology, Graduate School of Medicine, Hokkaido University, Sapporo, Japan.
Abo
Daisuke
D
Aoyama
Hidefumi
H
Furuta
Yasushi
Y
Onimaru
Rikiya
R
Onodera
Shunsuke
S
Sawamura
Yutaka
Y
Ishikawa
Masayori
M
Fukuda
Satoshi
S
Shirato
Hiroki
H
D000328:Adult; D000368:Aged; D003390:Cranial Nerve Neoplasms / Q000473:pathology / Q000532:radiotherapy*; D019583:Dose Fractionation, Radiation; D005154:Facial Nerve / Q000473:pathology; D005155:Facial Nerve Diseases / Q000473:pathology / Q000532:radiotherapy*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008866:Microsurgery / Q000009:adverse effects; D008875:Middle Aged; D009442:Neurilemmoma / Q000473:pathology / Q000532:radiotherapy*; D009802:Oculomotor Nerve / Q000473:pathology; D015840:Oculomotor Nerve Diseases / Q000473:pathology / Q000532:radiotherapy; D013238:Stereotaxic Techniques; D016896:Treatment Outcome; D014276:Trigeminal Nerve / Q000473:pathology; D020433:Trigeminal Nerve Diseases / Q000473:pathology / Q000532:radiotherapy; D047368:Tumor Burden; D055815:Young Adult