Lymph node yield independently predicts local recurrence in papillary thyroid cancer.

Background: Lymph node yield (LNY) is a validated quality control parameter in colorectal cancer surgery, with >12 nodes reflecting an adequate oncological resection. No formal guidelines exist in the context of central and lateral compartment lymph node dissection for papillary thyroid cancer (PTC). This study aimed to investigate the association between LNY and regional recurrence in PTC patients, and to define a threshold LNY that indicates adequate compartmental lymphadenectomy.

Methods: A retrospective analysis of patient data (1992-2022) was conducted using "The University of Sydney Endocrine Surgery Unit" database. Patients undergoing either prophylactic or therapeutic dissection of the central compartment or therapeutic dissection of the lateral compartment for PTC were included. Multivariate logistic regression analysis was performed to examine the relationship between nodal yield and local recurrence.

Results: On multivariate analysis, a central LNY ≤3 was an independent adverse prognostic factor for central recurrence (odds ratios [OR] 2.19, 95% confidence intervals [CI] 1.15-4.17, and p = 0.018) and a lateral LNY ≤20 was independently predictive of lateral recurrence (OR 2.45, 95% CI 1.24-5.31, and p = 0.007).

Conclusions: This study highlights the association between LNY and local recurrence in PTC. Our findings suggest that minimum LNY thresholds (>3 for central and >20 for lateral) may serve as indicators of adequate dissection. Further research should validate these findings across healthcare centers.