Thermal Ablation for T1N0M0 Papillary Thyroid Carcinoma: A Long-term Multicenter Comparative Study with Subgroup Analysis.

OBJECTIVE

To evaluate the long-term efficacy of thermal ablation (TA) for T1N0M0 papillary thyroid carcinoma (PTC) and compare outcomes between unifocal T1a PTC and unifocal T1b PTC and between unifocal T1a PTC and multifocal (≤3 nodules) T1a PTC.

MATERIALS AND

METHODS

This multicenter retrospective study included 495 patients with T1N0M0 PTC from eight hospitals with a median follow-up of 79 months, including 397 unifocal T1a, 49 unifocal T1b, and 49 multifocal T1a patients. The primary outcomes were disease progression and disease-free survival. Secondary outcomes included the technical success rate, volume reduction rate (VRR), complete disappearance rate, and complications. Univariate and multivariate Cox regression analyses were performed to identify risk factors for disease progression.

RESULTS

The disease progression rates were 4.3% (17/397) for unifocal T1a, 8.2% (4/49) for unifocal T1b, and 14.3% (7/49) for multifocal T1a PTC, with median follow-up durations of 81, 75, and 64 months, respectively. No significant differences were observed between the unifocal T1a and T1b groups (p=0.394), whereas progression was significantly higher for patients with multifocal T1a PTC than for patients with unifocal T1a PTC (p=0.010). New tumor development (4.4%) was more common than lymph node metastasis (LNMs) (1.8%) in the overall cohort. Among the 28 patients with disease progression, 25 underwent a second TA, with successful disease control in 96% (24/25) of the patients during a median follow-up of 40 months after retreatment. Multifocal tumors were the only independent risk factor for disease progression (HR: 5.601; p=0.001). Secondary outcomes included a 100% technical success rate, a 100% median VRR, and 99.0% complete tumor disappearance. The overall complication rate was 2.8%, with transient hoarseness being the most common major complication (2.2%).

CONCLUSION

This long-term multicenter study demonstrated that TA is a safe and effective treatment for T1N0M0 PTC. Although multifocality was identified as an independent risk factor for disease progression, second ablation therapy can effectively control new tumors or LNM.