Impact of Reclassification of Oncocytic and Follicular Thyroid Carcinoma by the 2022 WHO Classification.

Background: The 2022 WHO Classification categorizes oncocytic (OTC) and follicular thyroid carcinoma (FTC) based on the degree of capsular and vascular invasion into minimally invasive (MI), encapsulated angioinvasive (EA) and widely invasive tumors (WI). While associations with clinical outcomes have been studied extensively in FTC, robust clinical data are lacking for OTC. We aimed to investigate the impact of the reclassification of OTC and FTC by the 2022 WHO Classification on clinical outcomes.

Clinical and Histopathological Risk Factors for Radioactive Iodine-Refractory Follicular and Oncocytic Thyroid Carcinoma.

Context: Risk factors for radioactive iodine (RAI)-refractory disease in follicular (FTC) and oncocytic thyroid carcinoma (OTC) are unknown.

Objective: The aim of this study is to identify clinical and histopathological risk factors for RAI-refractory disease in FTC and OTC patients, facilitated by an extensive histopathological revision.

Methods: All adult FTC and OTC patients treated at Erasmus MC (the Netherlands) between 2000 and 2016 were retrospectively included.

Tumor size and presence of metastases in differentiated thyroid cancer: comparing cohorts from two countries.

Objective: Incidence of thyroid cancer varies widely, even across neighboring countries. Data on this phenomenon are largely lacking but are likely related to differences in health care systems. Therefore, we explored whether there are differences between populations from these 2 countries with respect to the relationship between tumor size and advanced disease.

Evaluating Disease-specific Survival Prediction of Risk Stratification and TNM Systems in Differentiated Thyroid Cancer.

Background: Many countries have national guidelines for the management of differentiated thyroid cancer (DTC), including a risk stratification system to predict recurrence of disease. Studies whether these guidelines could also have relevance, beyond their original design, in predicting survival are lacking. Additionally, no studies evaluated these international guidelines in the same population, nor compared them with the TNM system.

Evaluating the use of a two-step age-based cutoff for the UICC/AJCC TNM staging system in patients with papillary or follicular thyroid cancer.

Background: The joint Union International Contre le Cancer and American Joint Committee on Cancer (UICC/AJCC) Tumor, Node, Metastasis (TNM) staging system for differentiated thyroid cancer (DTC) involves a single age cutoff as a prognostic criterion. Because a single cutoff is a dichotomization of what might be a sliding scale, using multiple age cutoffs might result into a better stage definition. The aim of our study was to investigate if using a two-step age-based cutoff would improve the TNM staging system regarding disease-specific survival (DSS).