Hashimoto's Thyroiditis: A "Double-Edged Sword" in Thyroid Carcinoma

Area of Science:

• Endocrinology
• Oncology
• Immunology

Background:

• The incidence of thyroid carcinoma (TC) and Hashimoto's thyroiditis (HT) has risen significantly in recent decades.
• Investigating the complex relationship between HT and TC is crucial for understanding disease development and patient outcomes.

Purpose of the Study:

• To conduct a meta-analysis to evaluate the association between Hashimoto's thyroiditis and the risk and progression of thyroid carcinoma.
• To synthesize evidence from existing studies to provide a comprehensive overview of this relationship.

Main Methods:

• Adherence to Meta-analysis of Observational Studies in Epidemiology (MOOSE) guidelines.
• Comprehensive literature search of PubMed, Embase, Web of Science, and Cochrane Library databases (January 1, 2010 - December 31, 2020).
• Meta-analysis of 39 original research articles, calculating pooled odds ratios and analyzing publication bias using funnel plots.

Main Results:

• Hashimoto's thyroiditis is a significant risk factor for thyroid carcinoma (pooled OR = 1.71) and papillary thyroid carcinoma (pooled OR = 1.67).
• Patients with papillary thyroid carcinoma and HT were more likely to have multifocal tumors.
• Conversely, the prevalence of extrathyroidal extension, metastasis, BRAF^V600E mutation, and recurrence was lower in patients with papillary thyroid carcinoma combined with HT.

Conclusions:

• Hashimoto's thyroiditis presents a dual role in thyroid carcinoma, increasing cancer risk while potentially offering protection against tumor progression.
• HT is identified as a risk factor for TC and PTC development.
• HT may act as a protective factor against the progression of papillary thyroid carcinoma.