Loizos Loizou

and 6 more

Background: Pediatric and adolescent thyroid cancer (PATC) incidence rates (IR) are increasing in many countries. We determined IRs, temporal trends and survival from PATC diagnosed in Cyprus during 1998-2017. Procedure: Patients aged 0-19 years, diagnosed with PATC in the Pediatric Oncology Registry of Cyprus were included. Crude IR (cIR), age standardized rates (ASRW), time trends and overall survival were analysed. Annual IRs and temporal trends were calculated using Microsoft Excel 2016 and Joinpoint Regression analysis. Results: Eighty-one cases (76.5% female, 23.5% male) were identified. The cIR (per 100 000 persons) were for both sexes 2.00 (95% CI 1.61, 2.49), females 3.15 (95% CI 2.45, 4.03) and males 0.92 (95% CI 0.58, 1.44). The annual percentage changes (APC) for cIR and ASRW were 7.5% (p < 0.05) and 7.6% (p < 0.05). The APC of cIR were for females 5.1%, males 8.4% and 15-19-year-olds 7.6%. The female to male RR (rate ratio) was 3.42 (95% CI 2.06, 5.74). The papillary carcinoma (PTC) represented 86.4% of all cases. The RR of 2nd (2008-2017) to 1st (1998-2007) periods for metastatic (regional) stages was 3.76 (95% CI 1.74, 8.31). Survival until 2018 was 100%. Conclusion: This population-based study demonstrated that IR in 0-19-year-olds was among the highest reported. Increasing time trends mainly affected both males and females aged 15-19 years with PTC, the dominant type. Increase of metastatic cases suggests a true increase of thyroid carcinogenesis rather than overdiagnosis. Although prognosis is excellent, rising IR is unexplained, indicating the need to identify causal factors.