Radiofrequency ablation for solitary T1N0M0 papillary thyroid carcinoma in the danger triangle area: a preliminary analysis.

ABSTRACT

OBJECTIVES: To evaluate the feasibility, efficacy, and safety of radiofrequency ablation (RFA) for solitary T1N0M0 papillary thyroid carcinoma (PTC) in the danger triangle area. METHODS: 94 participants (mean age 44.45 ± 13.08; 73 females) with solitary T1N0M0 PTC in the danger triangle area who underwent percutaneous RFA at the hospital from January 2018 to April 2020 were retrospectively analyzed. Key ablation procedures included sufficient paratracheal fluid isolation, low-power, and short active tip (5 mm working electrode). Tumor size changes at different time points after RFA, technical success rates, tumor disappearance, disease progression, and complications were recorded and compared. RESULTS: Contrast-enhanced ultrasonography revealed that complete tumor ablation was performed with a 100% success rate in these patients. Post-ablation, the maximum diameter and volume of the ablation zone increased at the first and third month (p < 0.001), followed by a gradual decrease in size, without significant difference by the 6th month. The tumor disappearance rate was 76.59% (72/94), with higher rates in the T1a group compared to the T1b group (80% [64/80] VS57.1% [8/14], p < 0.001). There were no local recurrences. The incidence of new lesions and LNM was 3.2% (3/94), limited to the T1a subgroup. Further ablation was successfully applied to all new lesions and LMN. Mild voice changes were the only complication, with a rate of 3.2% (3/94), resolved within 4 months after RFA. CONCLUSIONS: Sufficient paratracheal fluid isolation combined with a low-power, short active tip radiofrequency ablation strategy is a safe and effective method for treating solitary T1N0M0 PTC in the danger triangle area.

The 'danger triangle' area comprises the dorsal edge of the thyroid gland, the lateral tracheal wall, and the anterior edge of the esophageal wall. When PTC tumors are present within the danger triangle, there is only limited space available for ablation. Furthermore, the proximity of the tumor with the esophagus, trachea, and thyroid capsule can complicate technical treatment success, potentially increasing the chance of local tumor recurrence and nerve injury. Therefore, the most effective approach for managing PTC lesions within the danger triangle remains undetermined. The goal of this study was to clarify the viability of ultrasound-guided RFA as a means of managing solitary T1N0M0 PTC tumors within the danger triangle area, providing a foundation for future clinical decision-making efforts.