Endocrine Abstracts

JOINT112220

Objectives: Thyroid cancer is a rare malignancy in the pediatric population, however recently the incidence has been increasing. This study describes the presentation, management and outcomes of patients seen at our centre over the last twenty-two years.

Methods: A retrospective chart review of 42 patients was conducted and statistical analysis performed. Inclusion criteria: Diagnosis of thyroid cancer, age less than 18 years at diagnosis, managed at the Stollery Children’s Hospital between 2002-2024. There were no exclusion criteria. The presentation, investigations, management, and follow-up data were collected.

Results: Patients’ age at diagnosis ranged from 5 to 17 years, with a median of 15. 7 years and an average follow-up time of 10 years (+/- 6 years). Thirty-five patients (83%) had papillary carcinoma, five (12%) had follicular carcinoma, one (2%) had medullary carcinoma, and one (2%) was diagnosed with non-invasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP). Three patients were found to have hereditary cancer syndromes including DICER1, PTEN Hamartoma Tumour Syndrome and MEN2. Metastatic disease was identified in twenty-five patients (60%) at presentation, including 22/25 involving lymph nodes and 3/25 distant lung metastases. 8/42 patients (19%) had extrathyroidal extension and 15/42 patients (36%) had lymphovascular invasion. Molecular testing was not conducted routinely but is becoming more utilized. One patient’s pathology was indeterminate but demonstrated a PAX8/PPARG mutation. This prompted surgery, resulting in confirmation of follicular carcinoma. Two patients with distant lung metastases and persistent disease were tested. NTRK3 and RET gene variants were identified, both of which are associated with aggressive disease. All patients underwent thyroidectomy. Data describing postoperative parathyroid function was available in 12/42 (29%) patients. 7/12 (58%) developed hypoparathyroidism, of which 4/7 (57%) cases were permanent. Data regarding laryngeal nerve function was available in 14/42 (33%) patients. Acquired laryngeal nerve dysfunction resulting in permanent vocal cord paralysis was diagnosed in 2/14 (14%) patients. Radioactive iodine was used for 38/42 (90%) patients. No patient deaths were reported.

Conclusion: Pediatric thyroid cancer has a high burden of disease. The mortality rate is low but there is significant morbidity associated with treatment. Molecular studies are becoming an essential tool in management of thyroid cancer.