Value of Ultrasound Combined with Immunohistochemistry Evaluation of Central Lymph Node Metastasis for the Prognosis of Papillary Thyroid Carcinoma

Background: Papillary thyroid carcinoma (PTC) is often accompanied by cervical lymph node metastasis (LNM). The accuracy of the preoperative ultrasound diagnosis of central LNM (CLNM) is limited. LNM is a high-risk factor for local recurrence and may affect the prognosis. Factors not directly related to tumor proliferation are used for risk assessment in the tumor-node-metastasis (TNM) staging system for thyroid cancer. The present study aimed to investigate the value of ultrasound and immunohistochemistry in predicting the presence of CLNM and the prognosis of PTC. Patients and Methods: The ultrasound and immunohistochemistry features of 303 patients with first-ever PTC and who underwent surgery between 01/2014 to 12/2016 were analyzed, as well as the prognosis of the patients. Univariable and multivariable analyses were carried out to determine the risk factors of CLNM and recurrence. Results: Among 303 patients, 125 (41.3%) were pathologically confirmed with CLNM. Multivariable analysis showed that multifocality, taller-than-wide shape, grade III-IV blood flow, capsular invasion, Ki-67 10%, p53 >= 5%, T2 or T3 stages were independent risk factors for CLNM. The median follow-up was 56 months. Cox regression analysis showed that age >= 55 years, maximum tumor diameter >20 mm, multifocality, capsular invasion, Ki-67 5-10%, Ki-67 >10%, p53 >= 5%, T3 stage and N1a stage were independent risk factors for PTC recurrence. The Kaplan- Meier showed that recurrence-free survival (RFS) was different according to age (P=0.017), tumor size multifocality, capsular invasion, Ki-67, p53, T stage and N stage (all P<0.001). Conclusion: For PTC with rich blood flow, taller-than-wide shape, multifocality, capsular invasion, p53 >= 5%, Ki-67 >10%, T2 or T3 stages prophylactic CLNM dissection might be indicated. Age >= 55 years, maximum tumor diameter >20 mm, multifocality, capsular invasion, high Ki-67, p53 >= 5%, T3 and N1a stages affected the clinical outcome.