Risk factors of predicting lateral neck lymph node metastasis following solitary papillary thyroid carcinoma

Objective To evaluate the risk factors in terms of clinical characteristics and sonographic features regarding solitairy thyroid papillary carcinoma (PTC) for the lateral cervical lymph node metastasis(LLNM) and then to establish nomogram model. Methods All patients were confirmed to be solitary PTC in paraffin wax pathology after thyroidectomy in Fudan University Shanghai Cancer Center from January to September 2016. Meanwhile, the status of lateral cervical lymph node metastasis was determined referring to postoperative pathology. Clinical characteristics including gender, age, preoperative thyroid stimulating hormone (TSH), thyroglobulin (Tg), thyroglobulin antibody (TGAb), thyroid peroxidase antibody (TPOAb), central lymph node metastasis (CLNM) and sonographic features of the PTC lesion including maximum tumor diameter, location, aspect ratio, relation with thyroid capsule, echo, margin, acoustic halo, microcalcification were evaluated for the association with lateral cervical lymph node metastasis using univariate and multivariate logistic regression analyses. Then the nomogram model was established and its application value was evaluated using ROC. Results Out of 1 174 patients, 125 patients (10.6%) presented lateral neck lymph node metastasis and 10 patients presented skipping metastasis.Univariate analysis showed gender, preoperative Tg and TGAb, CLNM, maximum tumor diameter, location, close to the thyroid tumor capsule, echo, aspect ratio, acoustic halo, microcalcification were associated with LLNM(P<0.05). Binomial logistic regression analysis indicated CLNM, maximum tumor diameter of larger than 10 mm, superior or multiple location, microcalcification were independent risk factors of LLNM. The AUC of the nomogram model was 0.865, the sensitivity was 88.0%, the specificity was 75.2%, and the accuracy was 76.6%. Conclusions As for patients with single focal PTC, CLNM, larger lesions, microcalcification, superior location are associated with lateral neck lymph node metastasis. The nomogram model can be tried for clinical application. Key words: Ultrasonography; Papillary thyroid carcinoma; Lymph node metastasis; Risk factors; Nomogram