ABSTRACT
OBJECTIVE: To determine the significance of Delphian lymph node (DLN) involvement in thyroid cancer. SUMMARY BACKGROUND DATA: The DLN has long been regarded as a predictor of thyroid malignancy and indicator of advanced disease; however, there are no published data in relation to the thyroid. METHODS: A retrospective cohort study with data obtained from the University of Sydney Endocrine Surgery database and histopathology records. The study cohort comprised 1000 consecutive patients undergoing total thyroidectomy. RESULTS: The DLN was separately removed and identified as such in 263 of 1000 (26.3%) patients. Of 1000 patients 203 (20.3%) had a diagnosis of papillary/medullary cancer. Of this group 150 patients had surgery performed for suspected cancer, and in 53 the diagnosis of cancer was unsuspected. In only 1 case did the DLN operative appearance alert the surgeon to an otherwise unsuspected thyroid cancer. The DLN was separately identified in 103 patients with cancer and, in this group, 22 of 103 (21.4%) had DLN metastases. DLN involvement was associated with greater nodal disease (9.8 vs. 1.6 nodes; P < 0.001), larger tumor size (19.4 vs. 11.1 mm; P < 0.003) and younger age (41 vs. 47 years; P = 0.058). DLN involvement was highly predictive of further disease in the central compartment (sensitivity = 41%, specificity = 95%), moderately predictive of further disease in the lateral compartment (sensitivity = 50%, specificity = 88%), and strongly suggestive of further nodal disease in the neck (sensitivity = 64%, specificity = 100%). CONCLUSIONS: Although the clinical appearance of the DLN is not an accurate indicator of the presence of unsuspected thyroid cancer, metastatic involvement of the DLN is an adverse prognostic marker in papillary/medullary thyroid cancer. The presence of DLN metastasis in patients with thyroid cancer should alert the surgeon to the high probability of advanced disease and need for greater attention to the central and lateral lymph node compartments.
