Thermal ablation for papillary thyroid microcarcinoma in the isthmus: a systematic review and meta-analysis

The treatment strategy for isthmic papillary thyroid microcarcinoma (PTMC) remains controversial. Although preliminary studies have confirmed the safety and efficacy of thermal ablation (TA), systematic reviews focusing on isthmic PTMC are lacking. This study is the first meta-analysis to comprehensively evaluate the clinical value of TA for isthmic PTMC.

A comprehensive search was conducted across PubMed, EMBASE, Cochrane Library, and Web of Science databases from their establishment dates through February 21, 2025, aiming to locate relevant studies investigating TA-treated isthmic PTMC cases. Following PRISMA standards, two investigators independently carried out three essential procedures: screening eligible literature, collecting pertinent data, and assessing study quality through established evaluation criteria.

Five studies involving 364 patients were included. Primary outcomes showed that the volume reduction rate at 12 months post-TA was 98.27% (95% CI: 96.95-99.58), with 90.84% (95% CI: 70.08-100.00) achieving complete tumor disappearance. During follow-up, the local recurrence rate was 0.38% (3/364; 95% CI: 0.00-1.65), and the lymph node metastasis rate was 0.01% (1/364; 95% CI: 0.00-0.77). Regarding safety, the major complication rate was 0.06% (2/364; 95% CI: 0.00-0.09%), both transient voice hoarseness, with no severe complications or distant metastasis reported.

TA demonstrates excellent tumor control and safety for isthmic PTMC. However, current evidence is limited by retrospective study designs (80%) and short follow-up periods (mean <5 years). Future large-scale, multicenter prospective studies with longer follow-up are needed.

Registration number: INPLASY202520104; date: February 23, 2025.