Performance of the American Thyroid Association Risk Classification in a Single Center Cohort of Pediatric Patients with Differentiated Thyroid Cancer: A Retrospective Study

Table 1

American Thyroid Association Pediatric Thyroid Cancer Risk Levels (2015).

ATA pediatric risk level	Definition
Low	Disease grossly confined to the thyroid with N0/Nx disease or patients with incidental N1a disease (microscopic metastasis to a small number of central neck lymph nodes)
Intermediate	Extensive N1a or minimal N1b disease
High	Regionally extensive disease (extensive N1b) or locally invasive disease (T4 tumors), with or without distant metastasis

There were no clear definitions of minimal or extensive lymph node disease in the ATA pediatric thyroid cancer guideline. Therefore, for the present study we used the definition provided in the recent ATA Thyroid nodule and Differentiated Thyroid Cancer Guideline (extensive involvement if > 5 lymph nodes or size of ≥3cm in largest diameter).