Nodal Factors Predictive of Recurrence After Thyroidectomy and Neck Dissection for Papillary Thyroid Carcinoma

Background: Lymph node (LN) yield and ratio are considered important predictors of post-treatment outcomes for several human cancers. This study examined the association between nodal factors, including the LN yield and ratio, with recurrence after thyroidectomy plus central compartment neck dissection (ND) for papillary thyroid carcinoma (PTC). Materials and Methods: This retrospective study involved 2384 consecutive patients who underwent a thyroidectomy plus central compartment ND combined with (n=440) or without lateral compartment ND at the authors' tertiary referral center between 2006 and 2012. The number of harvested LNs, as well as other tumor and nodal findings, were carefully reviewed. Univariable and multivariable Cox proportional hazards regression models were conducted to predict recurrence and its association with clinicopathologic variables. Results: All nodal factors, including the positive number of LNs, ratio, and extranodal extension, were significantly associated with nodal and any-site recurrence after thyroidectomy, as well as the tumor size and multifocality (p<0.01). The multivariable analysis showed that tumor size, multifocality, LN ratio, and extranodal extension were independent factors predictive of post-treatment recurrence (p<0.05). The LN yield was higher in patients with nodal recurrence but did not significantly affect the nodal recurrence. Patients with a LN ratio >0.3 exhibited a 1.7-fold higher risk of post-treatment nodal recurrence than their counterparts (p<0.01). Conclusions: LN ratio is an independent determinant predictive of nodal and any-site recurrence following thyroidectomy for PTC.