Background: This study aimed to explore the risk factors of central lymph node metastasis (CLNM) in patients with clinical central lymph node-negative papillary thyroid carcinoma (PTC), and emphasize the guidance of the risk scoring model for prophylactic central lymph node dissection (pCLND) in patients with clinical lymph node-negative (cN0) PTC. Methods: A total of 582 patients with cN0 PTC who underwent unilateral/bilateral thyroidectomy and prophylactic central lymph node dissection (pCLND) in the Affiliated Hospital of Nantong University from January 2020 to February 2021 were retrospectively analyzed. Univariate and multivariate analyses were performed to determine the risk factors of cN0 PTC. According to the independent risk factors of patients with cN0 PTC, a risk-scoring model was established. Then, the rationality of this risk scoring model was verified by additional clinical data of 112 patients with cN0 PTC in the Affiliated Hospital of Nantong University from March 2021 to April 2021.Results: Among 582 cases of cN0 PTC, 53.6% of the patients with cN0 had CLNM. The independent risk factors for CLNM in patients with cN0 PTC included male gender, <45 years of age, tumor with a maximum diameter of ≥1.0 cm, tumor location: middle/lower poles of the thyroid gland, multifocality, and extrathyroidal extension (ETE), and some ultrasound features, such as intra-nodular vascularity, microcalcification, irregular shape, and infiltrative margin. According to independent risk factors, a 24-point risk scoring model was established to predict CLNM in patients with cN0 PTC.Conclusions: Currently, prophylactic central neck lymph node dissection is a controversial operation, which should be selectively performed only for high-risk patients with cN0 PTC. For cN0 PTC patients with scores ≥14 and high-risk patients, even if no CLNM is found before surgery, routine prophylactic CLND is recommended. In addition, for cN0 PTC patients with a score of fewer than 14 points, it is recommended to perform fine-needle aspiration (FNA) before surgery, carefully assess the condition of the central lymph nodes, and then select the best surgical plan based on the results of the assessment.

Background:The core goal of this article is to find some meaningful risk factors that can affect the postoperative hypoparathyroidism of thyroid cancer, create an effective prediction model on this basis, and use it to selectively implement routine prophylactic calcium supplementation for patients after thyroid carcinoma surgery. Methods:The clinicopathological characteristics of patients with papillary thyroid carcinoma (PTC) who underwent conventional bilateral total thyroidectomy (TT) + bilateral central lymph node dissection from January 2020 to August 2021 in the Affiliated Hospital of Nantong University were retrospectively analyzed.Firstly, this study analyzed the relationship between postoperative hypocalcemia and hypoparathyroidism.Then, we included many potential risk factors such as gender, age, body mass index (BMI), lateral lymph node dissection (LLND) and so on and also performed univariate and multivariate analysis of the independent risk factors for postoperative hypoparathyroidism in patients, and established a predictive scoring model.Results: Among the 401 patients with PTC, 50.1% developed postoperative hypoparathyroidism.There was significant difference in serum calcium concentration between normal parathyroid group and hypoparathyroidism group after thyroid carcinoma surgery. BMI <24 kg/m 2 , lateral lymph node dissection, multifocality, and extrathyroidal extension (ETE) were all identified as independent risk factors for postoperative hypoparathyroidism. Based on these independent risk factors, a nine-point risk scoring model was created to firstly assess the postoperative parathyroid function status of patients and then to determine whether routine prophylactic calcium supplementation is needed. Importantly, the area under the curve (AUC) of the risk scoring model is equal to 0.979.Conclusions: At present, prophylactic calcium supplementation after thyroid carcinoma surgery is a controversial postoperative treatment. It should be selectively implemented for high-risk patients with hypoparathyroidism after surgery. Routine prophylactic calcium supplementation is recommended for PTC patients with a score greater than or equal to 5, although there are no clinical symptoms of postoperative hypocalcemia caused by hypoparathyroidism. However, prophylactic calcium supplementation is not recommended for patients with PTC with a score of less than 5; if the patient develops hypocalcemia at the later stage, therapeutic calcium supplementation can then be implemented.