Preoperative Prediction of Lymph Node Metastasis in T1N0M0 Papillary Thyroid Carcinoma by Using Contrast-enhanced Ultrasound

Similarly, the burden of central lymph node metastasis affects the individualized management of patients with T1N0M0 papillary thyroid carcinoma (PTC): lymph node metastasis is a contraindication to thermal ablation; low-burden lymph node metastasis is suitable for lobectomy; and high-burden lymph node metastasis recommends total thyroidectomy. However, conventional preoperative imaging examinations have low efficacy in diagnosing central lymph node metastasis. This multicenter retrospective cross-sectional study enrolled 600 patients with T1N0M0 PTC who were admitted to our hospital from June 2018 to June 2025 and confirmed by postoperative pathology. Dynamic contrast-enhanced ultrasound (CEUS) images of the thyroid and lymph nodes before surgery were collected for all patients. Two senior ultrasound physicians unaware of the pathological results independently analyzed the images and extracted qualitative and quantitative CEUS features of lesions and suspicious lymph nodes. Taking postoperative pathological results as the gold standard, patients were divided into the high-burden metastasis group, low-burden metastasis group, and non-metastasis group. Univariate and multivariate Logistic regression analyses were used to screen independent predictors, construct a combined predictive model, and draw receiver operating characteristic (ROC) curves and decision curves to evaluate its diagnostic efficacy and clinical practicality. The primary outcome measure was the area under the curve (AUC), and the secondary outcome measures included sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and net benefit. This project is expected to achieve accurate preoperative prediction of the burden of central lymph node metastasis and realize precise and individualized treatment for patients with T1N0M0 PTC.

Sex

All

Inclusion Criteria

1. Patients with preoperative assessment of T1N0M0 papillary thyroid carcinoma who underwent initial surgical treatment at the medical centers participating in this study between June 2018 and June 2025.
2. Definitive diagnosis of papillary thyroid carcinoma confirmed by postoperative histopathological examination.
3. Preoperative conventional ultrasound and contrast-enhanced ultrasound (CEUS) examination of the thyroid and/or suspicious central lymph nodes were performed, with complete imaging data of acceptable quality for analysis.
4. Surgical procedures included thyroidectomy (lobectomy or total thyroidectomy) combined with central lymph node dissection (prophylactic or therapeutic) to provide a definitive pathological gold standard for lymph nodes.
5. Complete clinical pathological data and imaging data were retrievable from the Hospital Information System (HIS).

Exclusion Criteria

1. Preoperative receipt of any anti-tumor treatment targeting the thyroid (e.g., radiotherapy, chemotherapy, targeted therapy, or ablation therapy).
2. Complication with other types of thyroid malignant tumors (e.g., medullary carcinoma, undifferentiated carcinoma, etc.).
3. History of neck surgery or radiotherapy that may affect the structure of cervical lymph nodes.
4. Complication with other systemic diseases that may affect CEUS perfusion characteristics or imaging evaluation (e.g., severe heart failure, liver cirrhosis, etc.).
5. Allergy to components of the ultrasound contrast agent.
6. Missing key clinical or imaging data, making complete analysis impossible.

• BACKGROUNDRiley RD, Ensor J, Snell KIE, Harrell FE Jr, Martin GP, Reitsma JB, Moons KGM, Collins G, van Smeden M. Calculating the sample size required for developing a clinical prediction model. BMJ. 2020 Mar 18;368:m441. doi: 10.1136/bmj.m441. No abstract available. PMID 32188600
• BACKGROUNDRiley RD, Collins GS, Ensor J, Archer L, Booth S, Mozumder SI, Rutherford MJ, van Smeden M, Lambert PC, Snell KIE. Minimum sample size calculations for external validation of a clinical prediction model with a time-to-event outcome. Stat Med. 2022 Mar 30;41(7):1280-1295. doi: 10.1002/sim.9275. Epub 2021 Dec 16. PMID 34915593
• BACKGROUNDLuo ZY, Hong YR, Yan CX, Wang Y, Ye Q, Huang P. Utility of quantitative contrast-enhanced ultrasound for the prediction of lymph node metastasis in patients with papillary thyroid carcinoma. Clin Hemorheol Microcirc. 2022;80(1):37-48. doi: 10.3233/CH-200909. PMID 33252064
• BACKGROUNDYu Y, Shi LL, Zhang HW, Wang Q. Performance of contrast-enhanced ultrasound for lymph node metastasis in papillary thyroid carcinoma: a meta-analysis. Endocr Connect. 2023 Jan 19;12(2):e220341. doi: 10.1530/EC-22-0341. Print 2023 Feb 1. PMID 36524799
• BACKGROUNDLi QL, Ma T, Wang ZJ, Huang L, Liu W, Chen M, Sang T, Ren XG, Tong J, Cao CL, Dong J, Li J. The value of contrast-enhanced ultrasound for the diagnosis of metastatic cervical lymph nodes of papillary thyroid carcinoma: A systematic review and meta-analysis. J Clin Ultrasound. 2022 Jan;50(1):60-69. doi: 10.1002/jcu.23073. Epub 2021 Oct 8. PMID 34625988
• BACKGROUNDYang Z, Wang X, Tao T, Zou J, Qiu Z, Wang L, Du H, Chen N, Yin X. Diagnostic value of contrast-enhanced ultrasonography in the preoperative evaluation of lymph node metastasis in papillary thyroid carcinoma: a single-center retrospective study. BMC Surg. 2023 Oct 24;23(1):325. doi: 10.1186/s12893-023-02199-w. PMID 37875825