The value of preoperative clinical and sonographic characteristics of clinically node-negative papillary thyroid carcinomain predicting central lymph node metastasis

Objective To investigate the association of preoperative clinical and sonographic characteristics of clinically node-negative (cN0) papillary thyroid carcinoma (PTC) with central lymph node metastasis (CLNM). Methods A total of 514 patients with PTC confirmed by pathology in our hospital were included in the retrospective analysis. Clinical and sonographic characteristics were assessed including age, gender, tumor size, and the distance between the tumor and the capsule. These cases were all diagnosed as cN0 according to clinical and sonography examinations. And the cases were divided into CLNM(+ ) group and CLNM(-) group based on the pathological results. Then statistical analysis was used to evaluate the correlation between CLNM and risk factors of cN0 PTCs. Results ①Of the 514 cN0 PTC cases, 211 cases (41.1%) were CLNM (+ ) and 303 cases (58.9%) were CLNM (-). ②With the presence of capsule invasion in the ultrasound examination, the probability of CLNM(+ ) group was higher than that of CLNM(-) group (62.1% vs 37.9%). ③In the 364 cases without capsule invasion, the probability of CLNM (+ ) was significantly increased when the distance between the tumor and the capsule was <1.5 mm (88.8% vs 11.2%). ④Multivariate analysis showed that risk factors independently associated with CLNM included age <45 years old, tumor maximum diameter ≥10 mm, and the distance between the tumor and the capsule <1.5 mm, among which the distance between the tumor and the capsule <1.5 mm had the highest OR value. Conclusions In cN0 PTC patients, CLNM is associated with age, size and the distance between the tumor and the capsule. Key words: Ultrasonography; Papillary thyroid carcinoma; Central lymph node metastasis