OBJECTIVETo evaluate the role of preoperative ultrasonography in detecting early cervical lymph node metastasis in differentiated thyroid carcinoma.

METHODSData were reviewed retrospectively from medical records between July 2003 and July 2005, in which patients were divided into 2 groups: group A (study group): 51 (55 sides) patients of differentiated thyroid carcinoma patients with impalpable node but with ultrasonic positive nodal metastasis; group B (control group): 57 (64 sides) patients with preoperative palpable cervical lymph nodes. All patients had been undergone modified neck dissection. The preoperative ultrasonographic results and the preoperative pathologic finding had been compared in group A.

RESULTSIn 51 patients (55 sides of preoperative positive ultrasonography 49 sides had been demonstrated cervical lymph nodes metastasis pathologically. The sensitivity of ultrasonography was 89.1%. Ultrasonography detected cervical lymph node believed to be uninvolved by physical examination in 41.2% of patients. 65.5% of the cervical lymph metastasis was multilevel and the most frequent involvement site was middle neck and the involvement rate was 70.9% in ultrasonography. 75.5% of the cervical lymph metastasis was multilevel and the most frequent involvement site was level Ill (65.3%) in pathologic finding.

CONCLUSIONSPreoperative ultrasonograpy is a mainstay in detecting cervical lymph nodes metastasis in thyroid cancer patients. It can detect the early cervical lymph node metastasis and localize the position of the cervical metastasis. All the thyroid cancer patients should undergo preoperative ultrasonography and the extent of the neck dissection relies on the preoperative ultrasonic finding of the neck.