Abstract / Summary
Objective: To evaluate the efficacy and safety of ultrasound (US)-guided radiofrequency ablation (RFA) for low-risk T1N0M0 papillary thyroid carcinoma (PTC), with emphasis on T1a versus T1b outcomes and longitudinal volume regression.
Materials and methods: MEDLINE, EMBASE, Cochrane Library, and KoreaMed databases were searched for studies published between January 2000 and March 2025. Both single-arm and comparative studies were eligible when RFA outcome data could be extracted independently. Thirty-five studies (9,787 tumors) were included in the analysis. Pooled estimates for complete disappearance, persistent tumors, disease progression, and complication rates were calculated using random-effects models. The volume-reduction ratio (VRR) was assessed at sequential follow-up intervals. Subgroup analyses were used to compare the outcomes for T1a and T1b PTCs.
Results: Among the 9,787 RFA-treated tumors, the pooled complete disappearance rate was 87.2% (I² = 97.9%). The pooled persistent-tumor rate was 0.1% (I² = 57.6%), and the pooled disease-progression rate, which reflected newly developed tumors (0.8%; I² = 63.9%) and lymph node metastasis (0.2%; I² = 19.8%), was 1.3% (I² = 70.0%). The VRR increased from 63.4% at 6 months to 88.7% at 12 months and reached 97.9% at 24 months. The pooled complication rate was 2.7% (I² = 93.0%), and the major complication rate was 0.02% (I² = 0%). Subgroup analyses showed lower complete disappearance rates (89.2% vs. 58.8%; P < 0.001) and higher persistent-tumor rates (0.02% vs. 2.2%; P < 0.001) in T1b tumors than in T1a tumors; disease progression (P = 0.234) and total complication rates (P = 0.794) were comparable.
Conclusion: US-guided RFA may provide effective tumor control with favorable safety in low-risk T1N0M0 PTC. However, heterogeneity across several efficacy outcomes limits the interpretability of these estimates. T1b PTCs showed lower complete disappearance and higher persistent-tumor rates than T1a PTCs, supporting the need for heightened surveillance of T1b disease.