Thyroid cancers in children and adolescents in France: Incidence, survival and clinical management over the 2000-2018 period.

[INTRODUCTION] Thyroid cancer is the first cause of endocrine malignancy among children. Over the past decades, an increase in the incidence rates (IR) has been observed around the world. Our study aimed to describe epidemiology, therapeutic management and survival rates of children and adolescents with thyroid cancer in France.

[METHODS] A population-based study was conducted between 2000 and 2018 in children and adolescents less than 17 years with a diagnostic of thyroid cancer.

[RESULTS] A total of 774 thyroid cancers were included: 579 papillary (PTC), 83 follicular (FTC), and 111 medullary carcinomas (MTC). PTC are more frequent in females and in adolescents whereas MTC mainly concerned children, mostly with a familial predisposition. Almost all patients underwent thyroidectomy, completed for most patients with PTC and FTC by radioiodine therapy. Cervical dissection was performed more frequently in patients having PTC and MTC compared to those with FTC. Between 2000 and 2018, thyroid cancers IR in children fluctuated between 1.3 and 3.2 per million, without any significant trend. The median follow-up time was 11.3 years in children, and 5.7 years in adolescents. The 5year-OS was greater than 98.5%.

[CONCLUSIONS] Population-based studies are crucial for better understanding and delineation of best management of rare diseases as thyroid cancers in pediatric and adolescent population. Considering the very favorable survival, a stratification should be proposed between cases at low risk and cases at high risk of relapse, in order to consider a strategy of therapeutic de-escalation in the most favorable cases.