Predictive Factors for Skip Lymph Node Metastasis and Their Implication on Recurrence in Papillary Thyroid Carcinoma

Area of Science:

• Endocrinology
• Oncology
• Surgical Pathology

Background:

• Papillary thyroid carcinoma (PTC) with skip lymph node (LN) metastases, classified as N1b, lacks central neck LN involvement.
• Understanding predictive factors for skip LN metastases and their impact on recurrence is crucial for managing PTC patients.

Purpose of the Study:

• To identify predictive factors for skip LN metastases in PTC patients.
• To evaluate the impact of skip LN metastases on recurrence-free survival (RFS) in PTC patients with pN1b classification.

Main Methods:

• Retrospective analysis of 334 PTC patients undergoing total thyroidectomy, central and lateral neck LN dissection, and radioactive iodine ablation.
• Evaluation of primary tumor size, LN involvement patterns, and stimulated thyroglobulin (Tg) levels as predictive factors.
• Statistical analysis including univariate and multivariate analyses for recurrence-free survival.

Main Results:

• Patients with skip LN metastases often presented with small primary tumors (≤1 cm) and isolated lateral neck LN involvement.
• Tumor size ≤ 1 cm was a significant predictor of skip LN metastases.
• Elevated stimulated Tg levels (>7.3 ng/mL) were strongly associated with shorter RFS (hazard ratio, 4.226; p < 0.001) on multivariate analysis.

Conclusions:

• While small primary tumor size predicts skip LN metastases in PTC, skip metastases themselves do not appear to influence RFS in pN1b patients.
• Elevated stimulated thyroglobulin levels are a significant predictor of recurrence in PTC patients with pN1b.
• Further research may refine risk stratification and treatment strategies for PTC with skip LN involvement.