Phase II trial of conformal radiation therapy for pediatric low-grade glioma

Thomas E. Merchant, Larry E. Kun, Shengjie Wu, Xiaoping Xiong, Robert A. Sanford, Frederick A. Boop

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Abstract

Purpose: 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. Materials and 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. Conclusion: 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.

Original languageEnglish (US)
Pages (from-to)3598-3604
Number of pages7
JournalJournal of Clinical Oncology
Volume27
Issue number22
DOIs
StatePublished - Aug 1 2009

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ASJC Scopus subject areas

  • Oncology
  • Cancer Research

Cite this

Merchant, T. E., Kun, L. E., Wu, S., Xiong, X., Sanford, R. A., & Boop, F. A. (2009). Phase II trial of conformal radiation therapy for pediatric low-grade glioma. Journal of Clinical Oncology, 27(22), 3598-3604. https://doi.org/10.1200/JCO.2008.20.9494