Radiation therapy for optic pathway and hypothalamic low-grade gliomas in children

Publication date: Available online 23 July 2017
Source:International Journal of Radiation Oncology*Biology*Physics
Author(s): Derek S. Tsang, Erin S. Murphy, Thomas E. Merchant
BackgroundThe long-term survival of pediatric patients with optic pathway or hypothalamic low-grade glioma (LGG) who receive radiation therapy (RT) has not been previously assessed.MethodsA retrospective study was performed of all patients with optic-hypothalamic pediatric LGG treated with RT at a single institution. Eligible patients were aged 21 years or younger at the time of RT and had localized LGG diagnosed by neuroimaging or histology. The median RT dose was 54 Gy, delivered in 30 fractions. Event-free survival (EFS) was defined as survival without progression or secondary high-grade glioma. Days were counted from the first day of RT.ResultsEighty-nine patients were included in the study, with a median follow-up of 12.5 years. Fourteen of the patients had neurofibromatosis type 1 (NF-1). The 10-year EFS was 61.9% (95% CI 31.2–82.1) for patients with NF-1 and 67.5% (95% CI 54.8–77.3) for those without NF-1. The 10-year overall survival (OS) was 92.3% (95% CI 56.6–98.9) for patients with NF-1 and 98.4% (95% CI 89.1–99.8) for those without NF-1. Pre-RT chemotherapy (which was more commonly given to younger patients) was associated with reduced EFS, whereas younger age was associated with reduced OS. Eight patients, including four with NF-1, developed possible radiation-induced neoplasms. The 10-year cumulative incidence of clinically-significant vasculopathy was 7.1% (95% CI 2.9–13.9); no child older than 10 years at the commencement of RT developed vasculopathy.Conclusion(s)Radiation is an effective treatment for optic-hypothalamic LGG. Older children without NF-1 have a low risk of late toxicity. RT can be considered for selected younger patients or individuals with NF-1 as a salvage treatment after progression.

Teaser

Radiation therapy for pediatric optic pathway or hypothalamic low-grade glioma establishes long-term disease control in most patients, with 10-year event-free survival (EFS) of greater than 60% and 10-year overall survival (OS) of greater than 90%. The presence of NF-1 did not affect EFS or OS. No child older than 10 years developed vasculopathy after receiving RT. Radiation is thus an effective treatment for optic-hypothalamic LGG, and older children without NF-1 have a low risk of late toxicity.


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