Phase II trial of conformal radiation therapy for pediatric low-grade glioma.
OBJECTIVE
The use of radiotherapy in pediatric low-grade glioma (LGG) is controversial, especially for young patients. We conducted a phase II trial of conformal radiation therapy (CRT) to estimate disease control by using a 10-mm clinical target volume (CTV) margin.


METHODS
Between August 1997 and August 2006, 78 pediatric patients with LGG and a median age of 8.9 years (range, 2.2 to 19.8 years) received 54 Gy CRT by using a 10-mm CTV and by targeting with systematic magnetic resonance imaging (MRI) registration. Tumor locations were diencephalon (n = 58), cerebral hemisphere (n = 3), and cerebellum (n = 17). Sixty-seven patients had documented or presumed WHO grade 1 tumors, 25 patients had prior chemotherapy, and 13 patients had neurofibromatosis type 1.


RESULTS
During a median follow-up of 89 months, 13 patients experienced disease progression. One patient experienced marginal treatment failure, eight experienced local failures, and four experienced metastatic failure. The mean and standard error 5- and 10-year event-free (87.4% +/- 4.4% and 74.3% +/- 15.4%, respectively) and overall (98.5% +/- 1.6% and 95.9% +/- 5.8%, respectively) survival rates were determined. The mean and standard error cumulative incidences of local failure at 5 and 10 years were 8.7% +/- 3.5% and 16.4% +/- 5.4%, respectively. The mean and standard error cumulative incidence of vasculopathy was 4.79% +/- 2.73% at 6 years, and it was higher for those younger than 5 years of age (P = .0105) at the time of CRT.


CONCLUSIONS
This large, prospective series of irradiated children with LGG demonstrates that CRT with a 10-mm CTV does not compromise disease control. The results suggest that CRT should be delayed in young patients to reduce the risk of vasculopathy.
Merchant
Thomas E
TE
Dept of Radiological Sciences, Mail Stop 220, St Jude Children's Research Hospital, 262 Danny Thomas Pl, Memphis, TN 38105-3678, USA. thomas.merchant@stjude.org
Kun
Larry E
LE
Wu
Shengjie
S
Xiong
Xiaoping
X
Sanford
Robert A
RA
Boop
Frederick A
FA
D000293:Adolescent; D000367:Age Factors; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use; D001707:Biopsy, Needle; D001932:Brain Neoplasms / Q000188:drug therapy / Q000401:mortality* / Q000473:pathology / Q000532:radiotherapy*; D002648:Child; D002675:Child, Preschool; D003131:Combined Modality Therapy; D018572:Disease-Free Survival; D004307:Dose-Response Relationship, Radiation; D005260:Female; D005910:Glioma / Q000188:drug therapy / Q000401:mortality* / Q000473:pathology / Q000532:radiotherapy*; D006801:Humans; D007150:Immunohistochemistry; D053208:Kaplan-Meier Estimate; D018810:Magnetic Resonance Angiography; D008297:Male; D009361:Neoplasm Invasiveness / Q000473:pathology*; D009367:Neoplasm Staging; D011379:Prognosis; D011446:Prospective Studies; D011879:Radiotherapy Dosage; D020266:Radiotherapy, Conformal / Q000009:adverse effects / Q000379:methods*; D018570:Risk Assessment; D018709:Statistics, Nonparametric; D016019:Survival Analysis; D016896:Treatment Outcome; D055815:Young Adult