Central nervous system malignancies

Abstract

Central nervous system (CNS) tumours are the second most common malignancy in children and the most common form of solid tumours in childhood. Astrocytomas accounting for 52% are the most common entity throughout childhood and adolescence, with juvenile pilocytic astrocytomas accounting for about 20% of all tumours. Anaplastic astrocytomas and glioblastomas achieve about 15%. Embryonal tumours: medulloblastomas and PNETs, are the second most common entity (21%) and the most frequent type among high-grade tumours. Ependymomas are the third most frequent tumours (9%) and very common in the first 3 years of life. Rarer entities included germ cell tumours, gangliogliomas, craniopharyngiomas, atypical teratoid/rhabdoid tumours, choroid plexus tumours, and dysembryoplastic neuroepithelial tumours (DNT). Computed tomography is still an excellent initial study for brain tumours and may serve as an important complementary study to magnetic resonance imaging (MRI). MRI has revolutionized the diagnosis of brain tumours in children and nowadays it is widely considered as the gold standard for the imaging of all brain tumours. The traditional treatment modalities in paediatric neurooncology are surgery, radiotherapy and chemotherapy, applied either alone or in various combinations and sequences. The use of high dose chemotherapy has changed an approach to the treatment of young children with newly diagnosed medulloblastoma, PNET and possibly other malignant brain tumours of early childhood, as well as selected patients with recurrent germ-cell tumours. Despite significant advances in treatment modalities, CNS tumours are still the leading cause of cancer-related death in this age group. Many of children fortunate enough to survive their CNS tumours are left with lifelong deficits resulting from their intensive treatments. New therapeutic approaches will more specifically target the tumours, resulting in better tumour kills with fewer long-term side effects and improving the survivors quality of life. Patients with brain tumours represent everything that is positive and negative about current treatment: increasing cure rates, the promise of new treatments, deleterious effects of therapy, and a lack of understanding about the impact of current treatment on long-term survivorship. Patients, their parents and caregivers need to be oriented to the relative merits of all treatment options based on peer-reviewed data. The major hope for future improvements in childhood brain tumour management rests on the ability to translate laboratory advances, especially new understandings in the molecular genetics and biology of brain tumours, into more effective therapeutic approaches.