Isthmic papillary thyroid microcarcinoma: clinicopathological features and prognostic factors following isthmusectomy based on tumor size stratification
摘要
This study aimed to compare clinicopathological features and recurrence risk in clinically node-negative (cN0) solitary isthmic papillary thyroid microcarcinoma (PTMC) ≤ 5 mm and > 5 mm in diameter treated with isthmusectomy, and to identify predictors of recurrence.
MethodsA retrospective review was performed of 201 cN0 patients with solitary isthmic PTMC who underwent isthmusectomy between 2018 and 2024. Patients with preoperative high-risk features were excluded. Subgroup analysis compared clinicopathological characteristics between the ≤ 5 mm (n = 107) and > 5 mm (n = 94) groups. Univariate and multivariate Cox models were used to identify factors associated with recurrence-free survival (RFS).
ResultsSignificant differences were observed between the two groups in tumor size (p < 0.001), central lymph node metastasis (CLNM) (p = 0.009), microscopic extrathyroidal extension(mETE) (p < 0.001), and BRAFV600E mutation (p = 0.008). During follow-up, 9 patients (4.5%) developed recurrence. Recurrence was significantly associated with tumor size > 5 mm (p = 0.028), CLNM (p = 0.002), and a higher number of metastatic central lymph node (CLN) (p < 0.001). Receiver operating characteristic analysis identified metastatic CLNs > 3 as the optimal cut-off for predicting recurrence. Kaplan–Meier analysis demonstrated worse RFS in patients with tumors > 5 mm (p = 0.031). Multivariate analysis confirmed metastatic CLNs > 3 as an independent predictor of recurrence (HR 5.298, 95% CI 1.473–19.060, p < 0.001).
ConclusionThis study demonstrated that isthmic PTMC tumors > 5 mm were associated with a higher risk of recurrence. In addition, CLNM, especially a metastatic CLNs > 3, may have prognostic significance and should be considered in surgical decision-making for isthmic PTMC.