Three-dimensional conformal radiotherapy for astrocytic tumors involving the eloquent area in children and young adults.
OBJECTIVE
Although a gross total removal of astrocytic tumors offers a favorable prognosis, it is often difficult to achieve in the eloquent area of the brain. This study was conducted to investigate the possible gain of three-dimensional conformal radiotherapy (3DCRT) for astrocytic tumors located in the eloquent area in children and young adults.


METHODS
Twenty patients with astrocytic tumors received the radiotherapy. The median age was 17 years, ranging from 4 to 30 years. Fourteen low-grade tumors (seven pilocytic and seven diffuse), and six high-grade tumors (five anaplastic, one malignant pilocytic) were included. Tumors were located at the thalamus/hypothalamus in 12 cases, optic tract in one case, and the deep cerebral/cerebellar hemisphere in seven cases. A specific fixation device was used for 3DCRT. Forty-six Gy for low-grade tumors and 54 Gy for high-grade astrocytomas with 1.8-2.0 Gy per fraction were in principle employed as the standard regimen. Nominal radiotherapy fields ranged from 2.0 x 2.0 to 15.0 x 11.0 cm2. The median follow-up period was 42 months, ranging from 3 to 108 months.


RESULTS
The actuarial survival rate at 5 years was 68% +/- 13% for all patients. The actuarial survival rate for low-grade glioma was 79% +/- 14% at 5 years and 50% +/- 20% at 3 years for high-grade glioma. The actual progression-free survival rate was 83% +/- 11% at 5 years for low-grade glioma and 50% +/- 20% for high-grade glioma. A complete response was obtained in three (21%) of 14 patients with low-grade astrocytic tumors. Two patients with low-grade tumors and four of six with high-grade tumors died due to tumor progression with infield relapse but not marginal relapse. Twelve survivors with low-grade tumors showed no signs of relapse and no neurological, hormonal, or cognitive deterioration after radiotherapy and were able to attend their school or continue with a full-time job.


CONCLUSIONS
3DCRT is safe and effective for low-grade astrocytic tumors located in the eloquent area in children and young adults.
Nishihori
Taiga
T
Department of Radiation Medicine and Neurosurgery, Faculty of Medicine, Hokkaido University, Sappovo, Japan.
Shirato
Hiroki
H
Aoyama
Hidefumi
H
Onimaru
Rikiya
R
Komae
Takashi
T
Ishii
Nobuaki
N
Ikeda
Jun
J
Miyasaka
Kazuo
K
Sawamura
Yutaka
Y
Iwasaki
Yoshinobu
Y
D000293:Adolescent; D001254:Astrocytoma / Q000401:mortality / Q000473:pathology / Q000532:radiotherapy*; D001932:Brain Neoplasms / Q000401:mortality / Q000473:pathology / Q000532:radiotherapy*; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D008297:Male; D020266:Radiotherapy, Conformal; D016019:Survival Analysis