Development And Validation Of A C-TIRADS-based Nomogram For Malignant Risk Prediction Of Thyroid Nodules

Objectives:1.To analyze and screen the independent risk factors of thyroid malignant nodules,and to develop a nomogram based on Chinese Thyroid Imaging Reporting and Data System(CTIRADS)to predict the malignant risk of thyroid nodules.2.To evaluate the clinical value of the developed nomogram through evaluating discrimination,calibration and clinical utility by using internal and external validation.Methods:1.A total of 388 patients with thyroid nodules in the Department of Thyroid Surgery of Qilu Hospital of Shandong University from January 2020 to June 2021 were selected.Patients’ data were collected.270 patients from January 2020 to December 2020 were selected as the development group,and 118 patients from January 2021 to June 2021 were selected as the validation group.2.According to routine postoperative pathological results,patients in the development group were divided into benign nodules group and malignant nodules group.Independent risk factors for thyroid malignant nodules were screened out by univariate analysis and multivariate analysis.Visualized nomogram was developed to predict the malignant risk of thyroid nodules.3.The receiver operating characteristic(ROC)curves of development group and validation group were drawn,and the concordance index(C-index)was calculated to evaluate the discrimination of the nomogram;The calibration curves of the development group and the validation group were drawn to evaluate the calibration of the nomogram.Decision curve analysis(DCA)was used to evaluate the clinical utility of the nomogram in the development group and validation group,respectively.Results:1.There were 57 males and 213 females in the development group,aged from 18 to 85 years old,with an average age of about 45 years old.The patients in the development group were divided into two groups:benign nodules group(n=137 cases)and malignant nodules group(n=133 cases).2.Univariate analysis showed that there were statistically significant differences in age,free triiodothyronine(FT3),thyroid stimulating hormone(TSH),thyroglobulin(TG),antithyroglobulin antibody(TGAb),the location of nodules,the maximum diameter,revealing abnormal lymph nodes by ultrasound and C-TIRADS classification between benign and malignant nodules groups in the development group(P<0.05).3.Multivariate analysis showed that there were statistically significant differences in age,TSH,TG and C-TIRADS classification between benign and malignant nodules groups in the development group(P<0.05).4.There were 30 males and 88 females in the validation group,aged from 20 to 74 years old,with an average age of about 44 years old.The validation group was divided into two groups:benign nodules group(n=55 cases)and malignant nodules group(n=63 cases).There was no significant difference in age,TSH,TG and C-TIRADS classification between the development group and the validation group(P>0.05).5.The C-index of the nomogram developed based on age,TSH,TG and C-TIRADS classification was 0.981 in the development group and 0.951 in the validation group.The area under the receiver operating characteristic(AUROC)of the development group was 0.981(95%CI:0.967～0.996)for predicting malignant risk of thyroid nodules by using the nomogram and the AUROC of the validation group was 0.951(95%CI:0.909-0.992),indicating the nomogram had great discrimination.The calibration curves in both the development group and the validation group were quite close to the ideal curves,suggesting that there was a high consistency between the actual risk and the predicted malignant risk of thyroid nodules.In the development group and the validation group,DCA was higher than the two extreme lines in a large threshold probability interval,indicating that the nomogram had high clinical utility.Conclusions:1.Age,TSH,TG and C-TIRADS classification are independent risk factors for thyroid malignant nodules.2.The nomogram based on clinical features,laboratory examination and C-TIRADS classification is easy to use.It is helpful to realize efficient doctor-patient communication and assist in formulating individual diagnosis and treatment plans.3.The nomogram developed has high discrimination,calibration and clinical utility in both the development group and the validation group.It has strong ability for non-invasive prediction of malignant risk of thyroid nodules,and is expected to become an important tool for malignant risk prediction of thyroid nodules.