Incidence and significance of Delphian node metastasis in papillary thyroid cancer.

Overview

OBJECTIVE: The objective of this study was to determine the incidence and significance of Delphian node (DN) metastasis in papillary thyroid cancer. SUMMARY OF BACKGROUND DATA: Despite the historic association, the prognostic implications of thyroid cancer metastasis to the DN remain unclear. METHODS: Retrospective analysis of 101 patients who underwent thyroid surgery from 2007 to 2009 for papillary thyroid cancer, and had their DN harvested ab initio. Of these, 25 had metastatic disease to the DN. DN status was correlated with clinical and pathologic factors including age, gender, tumor size, histologic variant, extra-thyroidal extension (ETE), and central and lateral nodal metastasis. RESULTS: DN positivity was seen consequent to higher rates of ETE of the primary tumor (52% vs. 28%; P = 0.025) and is associated with further nodal metastases to the central (72% vs. 22%; P < 0.0001) and lateral (28% vs. 4%; P < 0.0001) neck compartments. DN positivity was also associated with heavier nodal burden, in terms of number of metastatic nodes (median 5 vs. 2 nodes; P = 0.005) and nodal size (median 1 cm vs. 0.5 cm; P = 0.03). CONCLUSIONS: Metastatic involvement of the DN is often associated with ETE and increased incidence of metastatic disease to the central and lateral neck compartments. If the DN is positive on intraoperative frozen section, careful evaluation of the central and lateral nodal compartments is essential.