Epidemiology and genetics of neonatal tumours

Neoplasms are rare in neonates, although somewhat more frequent than in older children. In Great Britain, for birth years 1988-2007, the National Registry of Childhood Tumours recorded 394 cases of cancer (including nonmalignant CNS tumours) in live-born infants less than 28 days of age. The risk of neonatal cancer was 27.6 per million live births or 1 in 36,170, equivalent to an incidence of 361 per million person-years and double the rate over the remainder of the first year of life. The most frequent cancers were germ-cell tumours (24%), neuroblastoma (23%), leukaemia (18%) and CNS tumours (13%). Cancers probably account for a minority of neonatal neoplasms, so that the total risk of benign and malignant tumours exceeds 1 in 18,000. While the short-term prognosis of neonatal cancer is rather poor, the probability of survival conditional on surviving one year from diagnosis is much higher than in older children. Survival from leukaemia, embryonal CNS tumours and rhabdomyosarcoma is especially poor for neonates, whereas neonates with neuroblastoma have much higher survival than children aged 1 year and over. The proportion of neonatal cancers associated with pathogenic germline mutations seems unlikely to be much lower than 10%; in addition, a substantial proportion are associated with chromosomal abnormalities. Exogenous risk factors are probably only relevant if exposure is prenatal. The most plausible from among the many that have been investigated are exposure to ionizing radiation and some pollutants during pregnancy and some dietary factors.