l Dr Roger J Packer Differences Between Adult and Pediatric Brain ~umors By Roger J. Packer MD, Senior VicePresident, Center for Neuroscience and Behavioral Medicine; Director, The Brain Tumor Institute; Director, Gilbert Neurofibromatosis Institute; Children's National Medical Center; Professor, Neurology and Pediatrics, The George Washington University, Washington, DC, USA C hildhood brain tumors are not just the same tumors that arise in adulthood. Brain tumors in children and adults differ significantly in their incidence, tumor uncommon supratentorial lesions are in children. When considering brain tumors: the suprasellar region (the area behind the only tumors that primarily arise in the eyes and on top of the pituitary gland) brain, adult tumors are ten times more and the pineal region. Each has its own common than those arising in children. specific types of presentation The majOrity of adult primary brain tumors tumor types. are malignant gliomas 6r meningiomas, primarily occurring In comparison, in the cerebral cortex. childhood brain tumors are rare, arising in 2.5 to 3 children per and array of As regards the types of tumors which arise in children, more children than adults_ will develop embryonal tumors, the most common of which is medulloblastoma. 100,000 at risk, but are the leading cause Because of the primitive nature of of canc\3r-related death in childhood childhood and embryonal brain tumors, they comprise the majority of all solid tumors are likely to spread to other parts of the occurring central nervous system early in illness or in those less than 18 years of . age. Approximately 50% of childhood type, and treatment. Overall, survival brain tumors are benign (especially rates for those with brain tumors are low-grade, pilocytic gliomas), and they at time of relapse. This is why treatment often has to be given to the entire brain and spine at the time of diagnosis, where tend to occur more frequently in the this type of approach However, the immaturity of the child's lower portions of the brain, called the needed in adult brain tumors. brain makes treatment decisions difficult, posterior fossa. Childhood especially in infants. can also arise in the cerebral cortex, as in childhood adulthood. There are two other potential hotspots rates are much better in children with for the development malignant lesions. As an example, better in childhood than in the adult years. The majority of adult tumors are metastatic lesions secondary to tumors such as cancers of the colon and I0 lung whereas metastatic B\'aill Tumour brain tumors of childhood is less commonly Despite the primitive nature of many brain tumors, overall survival malignant tumors than in adults with the survival rate for children with neuroectodermal medulloblastoma, ever, arise in adults, but make up a young child, can result in significant considerable progressive the most common malignant tumor of childhood, in tumors occurring especially in children greater tumors rarely, if percentage Such treatment, of childhood of in the very long-term cognitive, endocrinological, brain tumors. A major issue in the management than three years of age and having especially and psychological damage. This is another major difference brain tumors, in general, is the nihilistic between adults and children. Other is as high as 90% at five years; with the attitude often present approaching factors, including preoperative majority of children cured of their disease. malignant tumors compared However, the price paid for this high positive attitude mandatory to effectively complications, survival rate is daunting. manage childhood understood tumors amenable to complete resection, Even with apparent identical tumor that some childhood adult to the more brain tumors. It is true brain tumors, such status, postoperative development molecular biology of brain tumors strongly atypical teratoid/rhabdoid sequelae. suggests that brain tumors are different young children, carry a poor prognosis. the in adults and children. The molecular composition of childhood high-grade tumors in very However, overall, 75% or more of children diagnosed with a brain tumor chemotherapy, and poorly host genetic susceptibilities also playa significant as diffuse intrinsic brain stem gliomas and types, new information conceming neurologic neurologic role in the and severity of long-term There is increasing hope that the treatment of childhood brain tumors will improve significantly in the near gliomas does not fit neatly into the sub- within the first 18 months of life can be future. Over the past decade, groupings expected deal more has been learned about the used for adults and they are likely biologically different tumors. to be alive five years later, at least two-thirds of whom are likely cured a great molecular makeup of childhood brain of their disease. Since the majority of tumors. In time, the goal is to translate infrequently grade 2 tumors and are more children with primary central nervous this information into more personalized, likely to be pilocyti~ (grade 1) tumors system tumors can be expected which have a significantly different "cured" with initial treatment, prognosis than adult low-grade tumors. there has been a great deal of concern into management The majority of pilocytic tumors have a raised over the quality of life of survivors. tumors utilizing anti-blood vessel agents (antiangiogenesis drugs), anti- Childhood characteristic low-grade gliomas are molecular signature and a to be appropriately The majority of children with malignant safer treatment. Molecular-based therapies are now being incorporated of childhood brain far better prognosis than grade 2 tumors, brain tumors will require both radiation growth factor agents, and other biologic remaining benign throughout and chemotherapy approaches. The most common life. low-grade tumor for long-term disease control. For the embryonal tumors, Although exciting, a major challenge type in adults is the grade 2 tumor which radiation therapy usually needs to be in the future will be to determine has a tendency to mutate into higher given to the entire brain and spine to these biologic factors affect the immature grade lesions over a three to five year eradicate disease that has already spread central nervous system and making period of observation. to the neuroaxis (which may not even be sure that these treatments types, such as the atypical teratoid/ evident on neuroimaging not only in improved survival, but in an rhabdoid tumor and some primitive time of diagnosis. Other tumor studies) at the how actually result improved quality of life. Brain Tumour II