The incidence of medulloblastomas and primitive neurectodermal tumours in adults and children.

Medulloblastomas (MB) and primitive neurectodermal tumours (PNET) are known to affect children more than adults. To estimate the magnitude of the differences between the incidence of adults and children, the incidence rates, ratios and time trends of MB and PNET in children and adults are measured using data from the Surveillance, Epidemiology and End-Results (SEER) database. Between 1973 and 2007 in the SEER 9 registries, 1372 people were diagnosed with a MB and 530 with a PNET. The overall incidence rate of MB and PNET is approximately 1.5 and 0.62 per million population in the USA. Children (1-9 years of age) with MB had an incidence rate of 6.0, compared to 0.6 in adults, and therefore children are 10 times more likely to be affected by an MB than adults. Children are 4.6 times as likely to be afflicted by a PNET than adults. The difference in incidence rates based on sex existed only in children. Our study confirmed that the incidence rates of MB has not changed over time.