Hashimoto's Thyroiditis: A Protective Factor against Recurrence in BRAF-Wild Type Differentiated Thyroid Carcinoma

Area of Science:

• Endocrinology
• Oncology
• Pathology

Background:

• Hashimoto's thyroiditis (HT) is a known protective factor against lymph node metastasis in BRAF-mutated papillary thyroid carcinoma.
• The influence of HT on differentiated thyroid carcinoma (DTC) recurrence, particularly in the context of BRAF mutations, remains unclear.

Purpose of the Study:

• To investigate the effect of underlying HT on DTC recurrence.
• To analyze the impact of HT on BRAF-mutated DTC recurrence.

Main Methods:

• Retrospective analysis of 469 DTC patients.
• Stratification based on BRAF mutation and HT status.
• Multivariate regression analysis to identify risk and protective factors for recurrence.

Main Results:

• HT was associated with less aggressive tumors, including more microcarcinomas, less lymph node involvement, and significantly lower recurrence rates (2.9% vs. 11.9%).
• BRAF mutation correlated with increased lymph node involvement and nearly doubled recurrence rates (14.9% vs. 6.5%).
• HT was an independent protective factor, reducing recurrence odds by 70% (HR: 0.30). This protective effect was significant in BRAF-wild type tumors but not in BRAF-mutant tumors.

Conclusions:

• Underlying HT is an independent protective factor against DTC recurrence, significantly reducing risk.
• The protective role of HT against recurrence is maintained in BRAF-wild type DTC but is absent in BRAF-mutant DTC.
• HT status may enhance current risk stratification models for DTC patients, particularly considering BRAF mutation status.