Central lymph node characteristics predictive of outcome in patients with differentiated thyroid cancer.

Background: The aim of our study was to determine central compartment lymph node (LN) characteristics predictive of outcomes in patients with differentiated thyroid cancer (DTC) and pathologically confirmed positive central LNs, in the absence of lateral neck disease or distant metastases at presentation.

Methods: An institutional database of 3664 previously untreated patients with DTC operated between 1986 and 2010 was reviewed. Six hundred patients with central compartment nodal disease on histopathology were identified. Patient demographics, number of positive LNs, size of largest LN, and presence of extranodal spread (ENS) were recorded for each patient. Variables predictive of recurrence-free survival (RFS) were identified using the Kaplan-Meier method. Univariate analysis was carried out by the log-rank test and multivariable analysis was carried out using cox proportional hazard model.

Results: The median age of the cohort was 41 years (range 12-91 years). The median follow-up was 61 months (range 1-330 months). Neck recurrence occurred in 43 patients. Recurrence occurred in the central neck in 11 patients, lateral neck in 27 patients, and both compartments in five patients. Factors predictive of neck RFS on univariate analysis were higher T stage (p=0.007), increased number of positive LNs, increased LN diameter, and presence of ENS (p=0.001). Multivariable analysis of LN characteristics showed that the only statistically significant predictor of neck recurrence was the presence of ENS. Neck RFS at five years for patients with and without ENS was 84.7% and 94.5% respectively (p=0.001).

Conclusion: The LN feature most predictive of neck recurrence appears to be the presence of ENS in the positive central neck.