Patterns and temporal trends in the incidence of childhood and adolescence cancer in Cyprus 1998-2017: A population-based study from the Cyprus Paediatric Oncology Registry.

Background: Despite its rarity, cancer in children and adolescents (CAC) is a major health issue worldwide. The lack of appropriate cancer registries is an obstacle for defining its incidence and survival, and informing cancer control. As in Cyprus, CAC epidemiology has not previously been comprehensively examined, we determined incidence rates and temporal trends of cancer in the 0-19 age group during 1998-2017.

Methods: We established the population based Paediatric Oncology Registry of Cyprus (PORCY) for the period 1998-2017. World age standardised incidence rate per million children and adolescents per year (ASRW) were calculated and time trends were assessed using Joinpoint regression analysis. Comparisons were made with other countries using the International Incidence of Childhood Cancer, third volume.

Results: For all cancers combined, for ages 0-19-years, ASRW was 203.54 (95% CI 189.49, 217.59) one of the highest rates globally. The most frequent CAC were leukaemias followed by lymphomas, specified epithelial neoplasms and central nervous system tumours, differing to what is described in most other countries. For all cancers, both combined and individual types, except thyroid carcinoma (where incidence was rising), no significant temporal variation was found.

Conclusions: To inform cancer control activities, we conducted the first ever population-based epidemiological study of childhood and adolescent cancer (0-19 years) in Cyprus. The striking findings indicate high overall incidence rates that are among the world's highest, a higher frequency of lymphomas and thyroid cancer than brain tumours, and rising incidence for thyroid, but not for other, cancers. These novel findings, will help the formulation of hypotheses to provide explanation for the high rates for all CAC in Cyprus and may contribute to the global efforts for improving prevention of cancer in this age group.