Lobectomy versus total thyroidectomy in intermediate-risk papillary thyroid carcinoma: rethinking surgical extent from a retrospective cohort study

Background: Thyroid lobectomy is increasingly being performed on patients with low-risk papillary thyroid carcinoma (PTC) following the expanded guideline recommendations. However, the oncological safety of lobectomy for patients with intermediate-risk PTC remains uncertain. The present study aimed to compare recurrence-free survival (RFS) between lobectomy and total thyroidectomy in a large cohort of patients with intermediate-risk PTC. Methods: We retrospectively reviewed 1452 patients with intermediate-risk PTC who underwent thyroid lobectomy and total thyroidectomy at a tertiary referral center between 2016 and 2020. To address baseline heterogeneity, multivariable Cox proportional hazards regression and 1:1 propensity score matching (PSM) were performed based on age, sex, preoperative lymph node (LN) status, and tumor size. Results: Of the 1452 patients, 825 underwent lobectomy and 627 underwent total thyroidectomy. During a median follow-up period of 62.1 months, the recurrence rate was significantly lower in the lobectomy group than in the total thyroidectomy group (2.1% vs. 5.9%, P < 0.001). However, multivariable Cox regression analysis revealed that surgical extent was not significantly associated with RFS (hazard ratio [HR] 1.09, 95% confidence interval [CI] 0.53–2.27, P = 0.813). Male sex and preoperative suspicious LN metastasis (cN1) were the only significant predictors of RFS. Subgroup analyses, stratified by preoperative lymph node status, showed no difference in RFS between the lobectomy and total thyroidectomy groups in either the cN0 or cN1 subgroups. After PSM (424 matched pairs), there was also no significant difference in RFS between the lobectomy and total thyroidectomy groups (HR 0.75, 95% CI 0.26–2.16, P = 0.594). Conclusion: In this large cohort study of patients with intermediate-risk PTC, lobectomy showed no significant difference in recurrence rates compared to total thyroidectomy, regardless of preoperative LN status. These results suggest that, for appropriately selected intermediate-risk PTC patients, lobectomy with central LN dissection is a safe and feasible surgical option, offering reduced surgical morbidity and preserved thyroid function without compromising oncologic outcomes.