ObjectiveTo investigate the predictive value of pretracheal lymph node (Ⅵc) subdivision for contralateral central lymph node (CLN) metastasis in clinical lymph node negative (cN0) unilateral papillary thyroid carcinoma (PTC). MethodsThe data of patients with cN0 unilateral PTC who initially underwent total thyroidectomy and bilateral CLN dissection in the Department of Thyroid Surgery of West China Hospital, Sichuan University from July 2017 to June 2021 were collected retrospectively. The Ⅵc subdivision was divided into right anterior trachea (Ⅵc1) and left anterior trachea (Ⅵc2); If the lymph nodes crossed the middle line of trachea, which would be included in the side of cancer focus. ResultsA total of 175 patients were included in this study, and the incidences of lymph nodes metastasis in the prelaryngeal (Ⅵd), Ⅵc, ipsilateral Ⅵc, contralateral Ⅵc, ipsilateral central, and contralateral central regions were 54 cases (30.9%), 118 cases (67.4%), 85 cases (48.6%), 72 cases (41.1%), 108 cases (61.7%), and 43 cases (24.6%), respectively. The results of the univariate analysis found that the contralateral CLN metastasis was associated with the lymph node metastases of Ⅵd, Ⅵc, contralateral Ⅵc, and ipsilateral central regions; The results of the multivariate analysis found that the lymph node metastases of Ⅵd and contralateral Ⅵc regions increased the probability of contralateral CLN metastasis (OR=4.444, P<0.001; OR=6.655, P=0.001). ConclusionsFrom the results of the study,Ⅵc subdivision is reasonable and effective, and has a certain predictive value for the metastasis of contralateral CLN in cN0 unilateral papillary thyroid carcinoma. And bilateral CLN dissection should be recommended in patients with a positive intraoperative frozen section result of contralateral pretracheal lymph node metastasis.
ObjectiveTo evaluate the predictive value of intraoperative frozen section analysis of the Delphian lymph node (DLN) and pretracheal lymph node (PLN) for central lymph node metastasis (LNM) and recurrence risk stratification in patients with differentiated thyroid carcinoma (DTC). MethodsThis retrospective study included 133 DTC patients who underwent initial surgery with intraoperative frozen section evaluation of the DLN and PLN at the Department of Thyroid and Breast Surgery, Union Hospital, Wuhan, between January 2023 and December 2024. Receiver operating characteristic (ROC) curves were used to assess the predictive value of DLN/PLN metastasis count and ratio for central LNM and recurrence risk stratification. The concordance between intraoperative frozen pathology and final postoperative pathology was also evaluated. ResultsMultivariate analysis identified age (<20 or >50 years) as protective factor (OR=0.332, P=0.012) and capsular invasion as risk factors for DLN/PLN metastasis (OR=2.823, P=0.017). DLN/PLN metastasis number and ratio showed strong predictive performance for central LNM >5 nodes, with AUC of 0.913 [95%CI (0.841, 0.986), P<0.001] and 0.910 [95%CI (0.837, 0.983), P<0.001], and optimal cut-off values of 1.5 nodes and 45.00%, respectively. For predicting intermediate-to-high recurrence risk, AUCs were 0.818 [95%CI (0.740, 0.895), P<0.001] and 0.800 [95%CI (0.720, 0.880), P<0.001], with cut-offs of 0.5 nodes and 26.79%, respectively. Intraoperative frozen pathology demonstrated a sensitivity of 88.00% (66/75), specificity of 100.00% (58/58), positive predictive value of 100.00% (66/66), and negative predictive value of 86.57% (58/67). Concordance with postoperative pathology was high, with a Kappa value of 0.849 [95%CI (0.761, 0.937), P<0.001] and an intraclass correlation coefficient of 0.917 [95%CI (0.885, 0.940), P<0.001]. ConclusionsIntraoperative frozen section analysis of the DLN and PLN demonstrates reliable predictive value for central LNM and recurrence risk stratification in DTC. This method may help identify patients who could benefit from an extended surgical approach and is recommended as a valuable adjunct to intraoperative decision-making.