Incidence and survival of children with central nervous system primitive tumors in the French National Registry of Childhood Solid Tumors

In France, as in other developed countries, primary tumors of the central nervous system (CNS) represent the second most frequent neoplasm after leukemia and the leading cause of cancer-related death in childhood. They account for ∼25% of malignancies in children <15 years of age at diagnosis.1 This group of tumors, however, cannot be considered as a single entity because it is composed of different diagnostic categories, the largest being astrocytomas, ependymomas, central primitive neuroectodermal tumors (cPNETs, including medulloblastomas), and other gliomas.2 In line with the third version of the International Classification of Childhood Cancer (ICCC-3),3 the CNS tumors include tumors of cranial and paraspinal nerves. Intracranial tumors account for ∼90% of all CNS tumors in children. The proportion of cases without histological confirmation of diagnosis is larger than that of other childhood cancers. In our previous study, the diagnosis was documented by cytology/histology in 86% of CNS tumor cases versus 94% of all cancer cases.1 Contrary to the general rule of cancer registry recommendations, some nonmalignant neoplasms are also included in the CNS group because it is difficult to establish a borderline between benign and malignant neoplasms in the case of ependymomas, some gliomas, and miscellaneous or unspecified intracranial and intraspinal neoplasms.3 Many cancer registries routinely include nonmalignant CNS tumors. We report incidence and survival analyses from the French National Registry of Childhood Solid Tumors, in which the CNS tumors have been classified according to the ICCC-3.3