Childhood and adolescent cancer is rare: it represents from less than 0.5% (reported in Europe and North America) to 2% (in developing countries) of all cancer cases, but there are large variations in the reported incidence.
Geographical differences in incidence rates may suggest genetic or environmental exposures that affect the risk of childhood cancer. However, there is growing evidence that most, if not all, of the variations in incidence rates are due to high levels of underdiagnosis and underreporting in regions with lower observed incidence rates.
Professor Loizou added ‘The creation of adequate CAC registries everywhere could improve this situation. Cyprus is a high-income economy, although the epidemiology of childhood cancer was never before studied comprehensively. For this descriptive epidemiological assessment, we created the national population-based Paediatric Oncology Registry of Cyprus (PORCY).’
This first ever population-based descriptive epidemiology study of CAC in Cyprus found that, for all childhood cancers combined, Cyprus has among the highest age standardised incidence rate (ASRW) globally. Leukaemias represent the most frequent CAC – as is the case elsewhere. However, lymphomas, specified epithelial neoplasms (SEN) and central nervous system (CNS) tumours occupy the 2nd, 3rd, and 4th places respectively as the most frequent cancers in this age group, deviating from what is internationally reported.
Despite the high incidence rate, there was no significant temporal variation for all CAC combined. Nevertheless, Cyprus was found to have among the highest ASRW for thyroid cancer in the world and a significantly increasing temporal trend, affecting mainly females and the 15–19-year age group. These patterns found in a population never studied before are important and raise questions about their causes. Further research is needed to explore genetic, environmental, dietetic and other factors that may lead to novel insights regarding the high incidence of childhood cancer in Cyprus and carcinogenesis, and that could, perhaps, ultimately contribute to better control of CAC internationally.