Recent trends in the radiotherapy of pediatric gliomas.

The management of pediatric gliomas is controversial, and is greatly influenced by the site of origin of the tumor. For example, cerebellar low grade tumors are often cured by surgery alone. This is in contrast to the hypothalamic and optic system tumors which are usually not amenable to complete resection. For the low grade astrocytomas, the usual indications for adjuvant treatment include: recurrent tumors after initial complete resection or symptomatic tumors that have been incompletely excised. In addition, treatment is generally indicated in tumors with growth on follow-up imaging, even in the absence of symptoms. In selecting the optimal treatment, the relative efficacies of surgery, chemotherapy and irradiation must be balanced by the potential complications of therapy. The potential risks of delayed intervention include irreversible neurologic impairment and potential lower probability of tumor control. This chapter reviews recent trends in the radiotherapeutic management of pediatric low-grade and malignant astrocytomas, particularly the new more conformal techniques that hold the promise of reduced toxicity in children requiring irradiation.