Hashimoto's thyroiditis is negatively associated with lymph node metastasis in PTMC

Area of Science:

• Endocrinology
• Oncology
• Pathology

Background:

• The relationship between Hashimoto's thyroiditis (HT) and lymph node metastasis (LNM) in papillary thyroid microcarcinoma (PTMC) is not well-defined.
• Understanding this association is crucial for predicting PTMC behavior and guiding treatment strategies.

Purpose of the Study:

• To investigate the impact of Hashimoto's thyroiditis on the occurrence and characteristics of lymph node metastasis in patients with papillary thyroid microcarcinoma.
• To determine if HT influences the risk of central and lateral neck lymph node metastasis in PTMC.

Main Methods:

• A retrospective cohort study included 9929 patients with PTMC.
• Propensity score matching (PSM) was used to create comparable groups of patients with and without HT.
• Logistic regression analysis evaluated the association between HT and LNM characteristics.

Main Results:

• 24.1% of PTMC patients had concurrent Hashimoto's thyroiditis.
• After PSM, patients with HT showed significantly lower rates of central LNM (40.9% vs. 56.2%) and lateral LNM (11.6% vs. 14.2%).
• HT was also associated with reduced extranodal extension, fewer positive lymph nodes, and a lower lymph node ratio.

Conclusions:

• Hashimoto's thyroiditis demonstrates a negative association with lymph node metastasis in papillary thyroid microcarcinoma.
• HT may exert a protective effect, reducing the likelihood and extent of lymph node involvement in PTMC.