Learning Curve and Clinicopathological Features of Endoscopic Thyroidectomy in Hashimoto’s Thyroiditis–Associated Differentiated Thyroid Carcinoma: A Risk-Adjusted Analysis

<title>Abstract</title> <p>Objective To characterize the risk-adjusted learning curve of transareolar endoscopic thyroidectomy in patients with Hashimoto’s thyroiditis (HT) and differentiated thyroid carcinoma (DTC).To analyze their perioperative, pathological, and immunological features, thereby informing preoperative risk stratification and case selection. Methods This single-center retrospective study included 100 consecutive female patients who underwent endoscopic thyroidectomy performed by the same doctor, including 32 with HT and 68 without HT. We collected perioperative variables, complications, extent of lymph node dissection and nodal metastasis, aggressive pathological features, and TPOAb/TgAb indices. The primary endpoint was operative time. A risk-adjustment model was constructed, and the learning-curve breakpoint was estimated using risk-adjusted Cumulative Sum (CUSUM) and segmented regression. Spline fitting and multiple sensitivity analyses were performed to assess robustness. Perioperative and pathological outcomes were compared between groups, factors associated with central lymph node metastasis (CLNM) were analyzed using logistic regression. Associations of antibody status and titers with surgical and pathological parameters were also assessed. Results Operative time decreased markedly with accumulating experience and entered a relatively stable phase at approximately case 50. Compared with the non-HT group, the HT group had longer operative time and a higher lymph node yield. After risk adjustment, We find that HT did not alter the shape of the learning curve; this finding was consistently supported by multiple sensitivity analyses. Central lymph node metastasis was associated with capsular invasion and age, but not independently with HT. Antibody titers in the HT group also showed no consistent association with operative difficulty or aggressive pathological features. Conclusion HT does not materially alter the learning pattern of transareolar endoscopic thyroidectomy and should not be used as a basis for exclusion. With standardized technique and careful protection of critical structures, this procedure remains safe and feasible in patients with DTC and coexisting HT.</p>