Prognostic Implications of Lymph Node Yield in Central and Lateral Neck Dissections for Well-Differentiated Papillary Thyroid Carcinoma

Purpose: The aim of this study was to evaluate the relationship between lymph node yield (LNY) from central (CND) and lateral (LND) neck dissections and risk of recurrence in patients undergoing primary surgery for well-differentiated papillary thyroid carcinoma (WDPTC). Methods: Clinical data were reviewed from all patients with biopsy-proven WDPTC who underwent primary total thyroidectomy with CND or LND at the authors' institution from 2005 to 2009. Patient demographics and tumor characteristics were obtained, and clinical data with at least five-year follow-up were used. Within the CNDs and LNDs, total number of nodes removed (LNY), total positive nodes removed, and the ratio of positive lymph nodes to LNY were determined. Results: One hundred fifty-two patients were included in the study, with average follow-up of 69 months. Of 125 patients who underwent CND, 20 had central neck disease recurrence. The LNY of patients with central neck recurrence was significantly less than those who had no recurrence (2.5 vs. 10.3; p<0.0001). Of 71 patients who underwent LND, 23 had ipsilateral lateral neck disease recurrence. The LNY of patients with lateral neck recurrence was significantly less than those who did not recur (10.5 vs. 24.6; p<0.0001). Higher rates of recurrence were associated with smaller LNY in both groups. For both groups, lower LNY remains predictive of recurrence on multivariate analysis controlling for pT stage, pN stage, American Joint Committee on Cancer stage, and radioactive iodine treatment. Conclusions: Higher LNY in CNDs and LNDs is associated with lower rates of papillary thyroid carcinoma recurrence in the central and lateral neck. To minimize the risk of recurrence and the need for secondary therapy with revision surgery and/or radiation, surgeons should perform thorough, compartment-oriented CNDs and LNDs when nodal surgery is undertaken.