# Analysis of Risk Factors for High-Risk Lymph Node Metastasis in Papillary Thyroid Microcarcinoma

## TL;DR

This study identifies male sex and extranodal extension as risk factors for aggressive lymph node metastasis in a type of small thyroid cancer, helping doctors better assess and treat patients.

## Contribution

The study identifies male sex and extranodal extension as novel independent predictors of high-risk lymph node metastasis in papillary thyroid microcarcinoma.

## Key findings

- Male sex and extranodal extension were significant predictors of high-risk lymph node metastasis.
- Patients with lymph node metastasis had lower treatment response rates and higher recurrence rates.
- Recurrence-free survival was significantly shorter in patients with lymph node metastasis.

## Abstract

Papillary thyroid microcarcinoma is a small thyroid cancer that generally has favorable outcomes, but some patients may still develop lymph node metastasis and disease recurrence. This study aimed to identify key factors associated with more aggressive disease, particularly high-risk lymph node metastasis. We found that male sex and extranodal extension were significantly associated with high-risk features. These findings may help clinicians better assess individual patient risk and formulate more personalized treatment strategies to improve long-term outcomes.

Background: Papillary thyroid microcarcinoma (PTMC) is associated with certain features that carry an increased risk of local recurrence, underscoring the importance of preoperative risk assessment. This study investigated the clinicopathological factors associated with high-risk lymph node metastasis (HRLNM) and patient outcomes. HRLNM is defined as ≥5 metastatic lymph nodes and/or lateral neck metastasis. Methods: We conducted a retrospective review of 985 patients with PTMC who underwent thyroidectomy at the Kaohsiung Chang Gung Memorial Hospital from 2013 to 2022. Results: Among the 985 patients, 100 (10.2%) had lymph node metastasis (LNM), and 27% of these were classified as having HRLNM. Male sex (OR 3.61, p = 0.04) and extranodal extension (OR 3.76, p = 0.043) were independent predictors of HRLNM. Patients with LNM exhibited lower rates of excellent treatment response (75% vs. 87%, p = 0.001), higher recurrence rates (9.0% vs. 0.6%, p = 0.001), and an increased risk of distant metastasis (2.0% vs. 0%). Recurrence-free survival (RFS) was significantly shorter in patients with LNM (120.9 vs. 198.6 months, p < 0.001). Although HRLNM showed a trend toward reduced RFS (113.5 vs. 124.6 months, p = 0.177), its impact on long-term survival remains uncertain. Conclusions: Male sex and extranodal extension were significant risk factors for HRLNM in patients with PTMC. These findings highlight the need for individualized risk stratification to guide treatment strategies and improve patient outcomes.