Prognostic Value of the Number of Retrieved Lymph Nodes in Pathological Nx or N0 Classical Papillary Thyroid Carcinoma.

Abstract

This study evaluated the clinical implications of the number of retrieved central lymph nodes (LN) for the recurrence and recurrence-free survival (RFS) outcomes in patients with pathological Nx (pNx) or N0 classical papillary thyroid carcinoma (PTC). In total, 464 patients were enrolled following total thyroidectomy with central LN dissection. The risk factors related to recurrence and RFS were evaluated and compared between these groups. Age, primary tumor size, and number of retrieved central LNs were independent risk factors for recurrence according to multivariate analysis (p<0.05). The cut-off value for the number of retrieved central LNs related to recurrence was 4.5. Group 2 (pN0; ≥5 nodes) demonstrated a significantly higher proportion of patients with an ablation-stimulated thyroglobulin (sTg) level <2.0ng/mL (84.9 vs 61.1%; p<0.050) and control sTg level <1.0ng/mL (92.1 vs 79.6%; p<0.050) in comparison with patients in group 1 (pNx or pN0; 1-4 nodes). Perioperative complication rates were comparable between groups. The number of retrieved central LNs is an independent risk factor for recurrence, even among patients with pNx or pN0 classical PTC. A thorough central LN dissection may therefore improve the long-term RFS rate.