ESPE Abstracts

A worldwide increase in pediatric thyroid cancers incidence over the years has been observed. Although pediatric thyroid cancers tend to have a more aggressive course compared to adults, the survival rate is better. In this study, we aimed to examine the demographic, clinical, pathological, and laboratory characteristics, prognostic and risk factors of children with thyroid cancer.

Methods: We retrospectively analyzed 39 children with thyroid cancer presented between 2008 and 2021. The study included 34 patients with differentiated thyroid cancer (DTC) (87.2%) including one follicular thyroid carcinoma and 5 patients with medullary thyroid cancer (MTC) (12.8%).

Results: The female-male ratio of the patients was 1.2:1 (Similar in pubertal and prepubertal groups). Among the patient with DTC, 11.8% of them had previously known thyroid disease (2 Hashimoto thyroiditis, one Graves disease, one radiation-induced hypothyroidism), and 11.8% had a prior malignancy. Radiation exposure was detected in 23.5% of DTCs. Hashimoto thyroiditis was revealed in 4 more patients at initial evaluation of thyroid nodule, increasing the frequency of autoimmune thyroid disease to 26.6 % in DTCs. Ultrasonographic characteristics of the nodules, including size <1 cm in 4, were solid in 81.6%, hypoechoic in 76.3% and, microcalcifications was detected in %57.9. Fine needle aspiration (FNA) revealed Bethesda V or VI in 66.6%, Bethesda IV in %18.2, Bethesda III in %6,1, and Bethesda I or II in 9.1%. of the patients. The lymph node and lung metastases were detected in 58.8% and 15.4% of the patients, respectively. Papillary microcarcinoma (PMC) was detected in 15,2% of patients diagnosed with PTC. Although no vascular and lymphatic invasion and, no lymph node or lung metastasis were detected in PMCs, 2 out of 5 patients did not receive RAI treatment and both had local recurrences. MEN2 syndrome was diagnosed in 80% of the patients with MTC. Among the patients who were followed for ≥ 2 years (n=29), no evidence of the disease was found in 69.2%, and recurrent or persistent disease was found in 28,2%. One patient who presented with primary lung involvement died due to disease at 7,5 years of diagnosis (2.6%).

Conclusions: Autoimmune thyroid disease and radiation exposure were the major risk factors for DTCs in our cohort. Pediatric thyroid cancers are aggressive and a nodule cut-off size of 1 cm is not applicable for children. RAI treatment should be given to all pediatric PTCs regardless of the tumor size and grade. Initial lung involvement is a poor prognostic sign.