How Many Lymph Nodes are Enough in Thyroidectomy? A Cohort Study Based on Real-World Data

Area of Science:

• Oncology
• Surgical Pathology
• Head and Neck Surgery

Background:

• Limited lymph node examination after thyroidectomy poses a risk for occult nodal disease in papillary thyroid cancer (PTC).
• The optimal number of examined lymph nodes (ELNs) for PTC patients with clinically lateral lymph node metastasis (cN1b) is not well-defined.

Purpose of the Study:

• To determine the optimal number of examined lymph nodes (ELNs) for accurate staging in papillary thyroid cancer (PTC) patients with clinically lateral lymph node metastasis (cN1b).
• To assess the relationship between the number of ELNs and the likelihood of occult nodal disease and recurrence rates.

Main Methods:

• Retrospective analysis of 982 patients with cN1b PTC who underwent therapeutic neck dissection.
• Utilized beta-binomial distribution to calculate the probability of occult nodal disease based on ELN count.
• Performed recurrence-free survival analysis using the Kaplan-Meier method.

Main Results:

• Increased ELN counts correlated with a reduced rate of occult nodal disease.
• A minimum of 20 ELNs is required to achieve 95% confidence of detecting no occult nodal disease in cN1b PTC patients.
• Specific ELN thresholds were identified for different pathological T stages (pT1-pT4).

Conclusions:

• A minimum of 20 examined lymph nodes (ELNs) is essential for quality assessment of neck dissection in cN1b PTC.
• Accurate staging and risk stratification depend on adequate lymph node examination.
• This finding supports optimizing surgical protocols for PTC management.