Clinicopathological and Ultrasound Features as Risk Stratification Predictors of Clinical and Pathological Nodal Status in Papillary Thyroid Carcinoma: A Study of 748 Patients

Abstract Background: Papillary thyroid carcinoma (PTC) is the most common histological type of thyroid malignancy that tends to metastasize to cervical lymph nodes. In the present study, we aimed to investigate which clinicopathologic and ultrasound features of PTC are associated with clinical lymph node metastasis (LNM) and numbers of pathological LNM. Methods: From January 2016 to December 2018, we identified a cohort of patients with PTC who underwent cervical ultrasonography and were diagnosed through operation and pathology. Clinical N1(cN1) and >5 pathologic N1(pN1) was performed in accordance with a standardized protocol. A model to determine the intermediate risk stratification of the 2015 ATA was established using the outcomes of univariate and multivariate analyses. Results: we collected 748 PTC patients in the final inclusion criteria. From the analyses, primary tumor size >21mm, capsule contact, extrathyroidal extensions (ETE), postsurgical radioiodine (RAI) treatment and central LNM remained independent risk factors for cN1 in PTC patients. Multifocality, primary tumor size >21mm, capsule contact, ETE and RAI treatment are significant independent risk factors for >5 pN1. Primary tumor size >21mm, capsule contact, ETE and RAI treatment were independent risk factors for both cN1 and >5 pN1. Conclusions: We conclude that primary tumor size >21mm, capsule contact, ETE and RAI treatment were independent predictors of for intermediate risk of recurrence in patients with PTC. Ultrasonography is a good technique for the preoperative lymph node staging of PTC and is helpful for detecting LNM.