Ultrasonographic Differentiation of Cervical Lymph Nodes in Patients with Papillary Thyroid Carcinoma After Thyroidectomy and Radioiodine Ablation: A Prospective Study

Abstract

The objective of the present study was to validate an ultrasound (US) classification of cervical lymph nodes (LNs) in patients with papillary thyroid cancer (PTC) after thyroidectomy and radioactive iodine (131I) ablation. We performed a prospective study in which the patients were submitted to thyroidectomy and 131I ablation and then followed until neck US revealed LN(s) ≥5 mm. A total of 288 LNs from 112 patients with PTC were evaluated. Patient management was based on LN characteristics grouped according to the classification system studied here. The presence of microcalcifications and/or cystic degeneration of cervical LNs were highly suggestive of a metastatic etiology (specificity of 99.4%). In contrast, the most sensitive finding for LNs affected by PTC was the absence of an echogenic hilum (sensitivity of 100%). In the absence of these findings (microcalcifications, cystic degeneration, echogenic hilum), a metastatic etiology was the most likely in the case of a round LN (specificity of 89%). The differentiation of a spindle-shaped LN without a visible hilum by Doppler analysis permitted us to dichotomize an initial probability of metastases of 13% in 25% (with peripheral vascularization) versus 3.3% (without peripheral vascularization). Our results confirm that the classification proposed for cervical LNs in patients with PTC is valid for determining patient management following initial therapy.