International incidence of childhood brain and spinal tumours.

BACKGROUND: Intracranial and spinal cord tumours are the second most frequent type of childhood cancer after leukaemia, accounting for around 20% of cases in many regions of the world, yet there have been few studies of their incidence by histological type and subsite.
METHODS: Age-specific and age-adjusted incidence rates were calculated from data in the study, 'International Incidence of Childhood Cancer', co-ordinated by the International Agency for Research on Cancer.
RESULTS: The highest age-adjusted incidence, 31.4 per million, was observed in the Nordic countries, and rates between 24 and 27 per million were found in most other predominantly white Caucasian populations. In the US, black children had a significantly lower incidence (21.7) than whites (26.4). Lower rates were seen in South America, Africa and Asia, the lowest being those for Chinese populations, and for blacks in Africa, both below 15 per million. Among white populations, astrocytomas were the commonest histological type, often with an incidence of at least 10 per million, followed by medulloblastomas, 5-6 per million, and ependymomas, 2-4 per million. In other regions with lower incidence rates, these three types accounted for similar proportions of the total. Black children in the US had a higher incidence of craniopharyngiomas than whites and there was an unusually high incidence of pineal tumours in Japan, 0.9 per million compared with 0.3-0.4 in many other countries.
CONCLUSIONS: The low recorded total incidence in developing countries may be partly due to underascertainment. Differences in total incidence or in relative frequencies of particular histological types between Western countries and Japan and between ethnic groups in the US suggest a substantial contribution of genetic predisposition in their aetiology.