Analysis and prediction of contralateral central lymph node metastasis risk in unilateral papillary thyroid carcinoma with ipsilateral lateral cervical lymph node: a retrospective clinical study.

Abstract

Background: Papillary thyroid carcinoma (PTC) often metastasizes to lymph nodes, increasing recurrence risk and reducing survival. This study identifies predictors for contralateral central lymph node metastasis (Cont-CLNM) in unilateral PTC patients with ipsilateral lateral cervical lymph node metastasis (Ipsi-LLNM).

Methods: We retrospectively analyzed data, preoperative ultrasound features, and thyroglobulin (Tg) levels in unilateral PTC patients with Ipsi-LLNM treated at the Thyroid Surgery Department of Nanjing Drum Tower Hospital from August 2017 to August 2024. Least absolute shrinkage and selection operator (LASSO) regression was used for variable selection, with independent t-tests and Chi-squared tests assessing differences. Logistic regression analyses identified risk factors for Cont-CLNM, and a nomogram was validated using 1,000 bootstrap resamples. Decision curve analysis (DCA) evaluated clinical impact.

Results: Of 105 PTC patients, 56 (53.3%) had Cont-CLNM. LASSO regression identified three predictors: male sex, lymph node metastasis posterior to the recurrent laryngeal nerve (LN-prRLN), and elevated Tg levels. Multivariate regression confirmed these variables' association with Cont-CLNM. Internal validation yielded an area under the curve of 0.771 [95% confidence interval (CI): 0.684-0.857]. A nomogram was developed and validated through DCA.

Conclusions: Our findings indicate that combining male gender, LN-prRLN, and Tg levels effectively predicts Cont-CLNM, providing a basis for risk assessment in unilateral PTC.