Comparison of total thyroidectomy and lobectomy for intermediate-risk papillary thyroid carcinoma with lateral lymph node metastasis: a systematic review and meta-analysis

Abstract

Background: The 2015 American Thyroid Association guidelines recommend total thyroidectomy (TT) followed by radioactive iodine (RAI) therapy as the primary treatment modality for intermediate-risk papillary thyroid carcinoma (PTC) patients with lateral lymph node metastasis (LLNM). However, the supporting evidence remains insufficient. The clinical superiority of TT versus lobectomy (LT) in this patient population remains unclear, and the optimal surgical approach for intermediate-risk PTC with LLNM continues to be debated.

Aim: This meta-analysis examined the clinical superiority of TT versus LT for intermediate-risk PTC with unilateral LLNM.

Methods: This PRISMA/AMSTAR-compliant meta-analysis (PROSPERO: CRDXXX) evaluated recurrence-free survival (RFS) in intermediate-risk PTC with unilateral LLNM. Systematic searches of PubMed, Web of Science, and Cochrane Library (2004-2024) combined MeSH terms and title/abstract: ("papillary thyroid carcinoma" OR "papillary thyroid cancer" OR "PTC") AND ("lateral cervical lymph node metastasis" OR "lateral neck lymph node metastasis" OR "lateral lymph node metastasis" OR "lateral cervical nodal metastasis" OR "N1b") AND ("thyroidectomy" OR "total thyroidectomy" OR "lobectomy"). Two investigators independently extracted data on surgical outcomes, adjuvant RAI therapy, and RFS metrics, with quality assessed via Newcastle-Ottawa Scale. Prespecified subgroup analyses examined RAI utilization and surgical extent impacts. Pooled hazard ratios (HR) with 95% confidence intervals (CI) were calculated using Review Manager 5.3, prioritizing adjusted HR. Heterogeneity was assessed via I2 statistics.

Results: Among 609 initially identified references, 8 studies met the inclusion and exclusion criteria, comprising 2,462 intermediate-risk PTC patients with unilateral LLNM. Of these, 53.3% (1,313/2,462) underwent TT, and 46.7% (1,149/2,462) underwent LT. Compared with the TT group, LT showed no statistically significant difference on RFS (HR = 1.08, 95% CI 0.83-1.40, p = 0.56). In subgroup analyses: Compared with TT + RAI, LT showed no significant difference in RFS (HR = 0.66, 95% CI 0.40-1.08, p = 0.10); Compared with TT + RAI, LT or TT alone showed no significant difference in RFS (HR = 0.65, 95% CI 0.41-1.03, p = 0.07); Compared with TT alone, LT showed no significant difference in RFS (HR = 1.16, 95% CI 0.63-2.12, p = 0.64); Compared with TT + RAI, TT alone showed no significant difference in RFS (HR = 0.87, 95% CI 0.42-1.81, p = 0.37).

Conclusion: For intermediate-risk PTC patients with isolated unilateral LLNM, TT and LT demonstrate comparable oncological outcomes in terms of RFS. Unilateral LLNM alone should not constitute an absolute indication for TT. When no additional high-risk features are present, LT may serve as a preferable alternative to optimize quality of life while maintaining oncological safety.

Keywords: lateral lymph node metastasis; lobectomy; papillary thyroid carcinoma; total thyroidectomy.