Radiation Therapy in the Management of Pediatric Brain Tumors

Abstract

Tumors of the brain constitute 17% of all malignant tumors among children younger than 20 years of age in the United States, making them the most common solid neoplasm and the second most common malignancy in children after leukemia. The annual incidence is approximately 2.9 cases per 100,000 children per year, representing 2000 new cases in the United States annually. The incidence of childhood brain tumors sharply increased in the 1980s, coincident with the wide availability of magnetic resonance imaging, but was stable from 1986 to 1995 (Gurney et al. 1996; Ries et al. 1999). Approximately 40% of children with brain tumors die of their disease (Duffner et al. 1986). The 5-year relative survival for these tumors increased in the United States from 59% during 1975–1984 to 67% during 1985–1994 (Ries et al. 1999). The histologic distribution of childhood brain tumors, shown in Table 27.1, is markedly different from that seen in adults. The relative frequency of malignant central nervous system tumors among children under 20 years of age is: astrocytomas 52%, primitive neuroectodermal tumors 21%, other gliomas 15%, ependymomas 9%,and others 3% (Ries et al. 1999). The supratentorial location predominates in infants as it does in adults, but infratentorial tumors constitute approximately half of all brain tumors in children 1–15 years of age. Radiation therapy is the mainstay of treatment of brain stem gliomas, and has an important role in the management of most other brain tumors. This chapter will discuss the role of radiation therapy in the management of the most common childhood brain tumors.