Background: The goals of this study were to analyze clinical factors that affect cervical lymph node metastasis (LNM) in papillary thyroid cancer (PTC), and to evaluate the diagnostic accuracy of preoperative ultrasound (US) and computed tomography (CT) of the neck.
Methods: The study sample included 589 consecutive patients who underwent surgery for PTC. Patient age and sex, number, size, and location of tumors, lymphovascular invasion, and extrathyroidal extension were evaluated as risk factors for central and lateral LNM.
Results: Increased risk of lymph node metastasis was found for male patients, <45 years old, with tumor size >1 cm, lymphovascular invasion, and extrathyroidal invasion. Cancers located in the upper neck had a higher relative risk of lateral metastasis than cancers located in the lower neck. Sensitivity of both US and CT imaging was higher for lateral (70-80%) than for central (42-47%) LNM. Specificity of US and CT was high (92-97%) for both central and lateral LNM. Using central lymph node size of greater than 5 mm as an indicator of metastasis, preoperative US had 58.3% sensitivity and 71.4% specificity.
Conclusions: Preoperative US and CT imaging are useful for identifying features that indicate a high risk of LNM and for determining appropriate management of PTC.