A Nomogram for Predicting Lateral Lymph Node Metastasis in Cases of Papillary Thyroid Micro-Carcinoma with Suspected Lymph Node Metastasis

The elevation for lateral lymph node metastasis (LLNM) plays an important role in therapeutic decision-making for thyroid carcinoma. A reliable forecasting model for LLNM in patients with papillary thyroid micro-carcinoma (PTMC) is needed, using clinicopathological characteristics. A total of 576 PTMC patients with suspicious lateral cervical lymph node (II, III, IV or V region) metastasis and known clinicopathological variables were randomly collected at Shenzhen Second People's Hospital. Cervical lymph node status of every patient was assessed by ultra-sonography (US). The patients in this cohort study underwent thyroidectomy and lateral neck lymph node dis-section. Univariate analysis and logistic regression analysis were performed to screen out the predictive variables associated with LLNM, and a nomogram was constructed by integrating clinicopathological features collected in our study. The overall LLNM rate was 23.0% (133/576). After statistical analysis, central lymph node metastasis (CLNM), prelaryngeal lymph node metastasis (PLNM), bilateral lesions, tumor location in thyroid (upper or lower), and gross extrathyroidal extension (ETE) were found to be independent predictive factors for LLNM (P < 0.01). The nomogram built to predict LLNM in PTMC patients passed the calibration step and the area under the receiver operating characteristic curve was 0.967, which showed that the nomogram we used had a good predictive effect. The nomogram constructed in this study has a good predictive value for LLNM, which will help thyroid surgeons to make a more accurate surgical plan for patients with PTMC. A strict preoperative evaluation and total thyroidect-omy and lateral neck dissection may be indicated when patients with PTMC have a high score.