Nomogram For Predicting Central Lymphnode Metastasis In CN0 Stage Papillary Thyroid Carcinoma And It’s Clinical Significance

Purpose: The aim of this study was to investigate the risk factors associated with occult central lymph node metastases(CLNM)in patients with papillary thyroid carcinoma(PTC)and to construct a predictive model.Combined with the complication rate of prophylactic central neck dissection(PCND),we provided a decision basis for prophylactic central lymph node dissection in patients with clinically lymph node negative(cN0)PTC.Methods: Patients who underwent thyroid surgery and were pathologically diagnosed with PTC from September 2016 to March 2022 at the Department of Glandular Surgery,Hebei Provincial People’s Hospital were selected as the study population.Clinical data of patients meeting the inclusion criteria were collected and patients were included in the model group.The clinical data of patients in the model group were analyzed and compared using univariate and multivariate logistic regression analysis to identify independent risk factors associated with occult CLNM in PTC,and a preliminary CLNM risk assessment model was constructed and a column line plot was drawn.Internal validation of the prediction model was performed using the Bootstrap method.Further clinicopathological data of PTC patients with the same condition as the model group from March 2022 to October 2022 were collected as the validation group for external validation.Patients were analyzed for the incidence of short-or long-term postoperative complications.Results: A total of 410 patients were included in the model group,of whom 200 had positive lymph nodes in the central region,with a metastasis rate of 48.8%(200/410).Multifactorial analysis revealed that male,age ≤45years,cancer foci located in the isthmus,bilateral cancer foci,tumor diameter ≥1 cm,extra-thyroidal invasion and calcification were independent risk factors for occult CLNM.The above risk factors were included in the model and used to construct predictive line graphs.Internal validation and external validation showed good discrimination and calibration of the model.In the model group,the area under the receiver operating characteristic curve(ROC)curve was 0.812(95% CI: 0.772-0.853).In the validation group,the area under the ROC curve was 0.866(95% CI: 0.783-0.949).calibration calibration curve showed good agreement between predicted values and observed variables in the model and validation groups.The decision curve shows that the model has good clinical practicability.The incidence of PCND complications was not significantly increased in our institution compared with other studies.Conclusion: In this study,risk factors for occult CLNM such as gender,age,tumor diameter,tumor located in the isthmus,ETE,bilateral cancer foci,and calcification were screened by multifactorial analysis,and patients with these factors should be carefully evaluated clinically for lymph nodes.The proportion of lymph node metastasis in the central region of PTC patients with negative clinical lymph nodes in this study was high,and it is recommended that PCND be performed in patients with high-risk factors to remove possible occult metastatic lymph nodes while ensuring safety.