Three-dimensional conformal fractionated radiotherapy for spinal schwannoma with a paravertebral or an intraosseous component.
BACKGROUND
We retrospectively evaluated the efficacy of three-dimensional conformal radiotherapy (3D-CRT) for spinal schwannoma.


METHODS
Nine patients with spinal schwannoma were treated with 3D-CRT. All patients had a paravertebral or intraosseous component. Tumor sizes ranged from 0.8 to 8.7 cm, with a median of 3.5 cm. The prescribed dose was 50 Gy in 25 fractions at the isocenter, except for 1 patient who received 66 Gy in 33 fractions for a large sacral tumor. The follow-up period ranged from 20 to 137 months, with a median of 72 months.


RESULTS
Tumor shrinkage within 3 mm occurred in 4 patients and tumor expansion within 3 mm occurred in 3. One tumor showed neither expansion nor shrinkage at the last follow-up. One patient experienced transient expansion by 8 mm in diameter at 12 months after the completion of radiotherapy (35-43 mm), and then the tumor size remained unchanged for 7 years. No severe late toxicity ≥ grade 3 was observed.


CONCLUSIONS
Only 1 of 9 tumors showed transit expansion over 3 mm after 3D-CRT, and severe late radiation toxicity was not observed. Use of 3D-CRT should be considered a treatment option for spinal schwannoma.
Department of Radiation Medicine, Hokkaido University Graduate School of Medicine, North 15 West 7, Kita-ku, Sapporo, 060-8638, Japan. ronimaru@pop.med.hokudai.ac.jp.
Rikiya
R
Onimaru
Department of Neurosurgery, Hokkaido University Graduate School of Medicine, Sapporo, Japan.
Kazutoshi
K
Hida
Department of Rehabilitation Science, Faculty of Health Science, Hokkaido University, Sapporo, Japan.
Naoki
N
Takeda
Department of Radiation Medicine, Hokkaido University Graduate School of Medicine, North 15 West 7, Kita-ku, Sapporo, 060-8638, Japan.
Shunsuke
S
Onodera
Department of Radiation Medicine, Hokkaido University Graduate School of Medicine, North 15 West 7, Kita-ku, Sapporo, 060-8638, Japan.
Yukiko
Y
Nishikawa
Department of Radiation Medicine, Hokkaido University Graduate School of Medicine, North 15 West 7, Kita-ku, Sapporo, 060-8638, Japan.
Takashi
T
Mori
Department of Radiation Medicine, Hokkaido University Graduate School of Medicine, North 15 West 7, Kita-ku, Sapporo, 060-8638, Japan.
Hiroki
H
Shirato
D000293:Adolescent; D000328:Adult; D000368:Aged; D002648:Child; D019583:Dose Fractionation, Radiation; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D021621:Imaging, Three-Dimensional; D008297:Male; D008875:Middle Aged; D009442:Neurilemmoma / Q000000981:diagnostic imaging / Q000532:radiotherapy*; D020266:Radiotherapy, Conformal / Q000379:methods*; D012189:Retrospective Studies; D013125:Spinal Neoplasms / Q000000981:diagnostic imaging / Q000532:radiotherapy*; D013131:Spine / Q000000981:diagnostic imaging; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome; D055815:Young Adult
Conventional fractionation; Fractionated radiotherapy; Paravertebral schwannoma; Spinal schwannoma; Three-dimensional conformal radiotherapy (3D-CRT)