Background: Thyroid cancer (TC) is a rare condition in children. It may be associated with radiation, iodine deficiency or familial inheritance.
Aims: The objectives of this study were to analyse the prevalence and incidence trends over 3 decades and clinical features of TC in the paediatric population in Lithuania.
Methods: We reviewed all TC cases diagnosed in children aged less than 18 years during the period 1980-2014 using medical records from 3 main hospitals in Lithuania where such TC cases are managed.
Results: During the 35-year period (1980-2014) there were 57 cases (45 females) of TC in children in Lithuania. The mean age at the time of diagnosis was 14.51 ± 0.52 years. The crude incidence rate of TC ranged from 0 to 0.93 cases per 100,000 children per year and the mean annual increase was 5.26% (p < 0.001). Papillary carcinoma was the most common histological type (73.7%). No association was found between the incidence of TC and the reported areas of radioactive contamination after the Chernobyl accident. In total, 8.8% of patients had secondary TC after initial radiotherapy of a primary oncologic disease.
Conclusion: The incidence of TC in the Lithuanian paediatric population between 1980 and 2014 ranged from 0 to 0.93 cases per 100,000 children per year and there was a 5.26% annual increase (p < 0.001), most probably related to the increased use of ultrasound testing.
Keywords: Chernobyl accident; Children; Paediatrics; Radiation; Secondary cancer; Thyroid cancer.