A novel parallel overlapping mode for complete ablation of large benign thyroid nodules in a single-session radiofrequency ablation.

BACKGROUND

Radiofrequency ablation (RFA) has been widely applied in patients with benign thyroid nodules (BTNs), and complete ablation in a single-session treatment brings great benefits to patients. While how the ablation should be planned and performed to achieve complete ablation in a single-session treatment in large BTNs remains unknown.

PURPOSE

To determine a more suitable ablation strategy for sufficient treatment in a single-session treatment.

MATERIALS AND METHODS

This retrospective study included 108 BTNs receiving RFA treatment. These patients were divided into two groups: group A using one insertion point with a fan-shaped overlapping mode and group B using multiple insertion points with a novel parallel overlapping mode. All the treatments used a hydrodissection approach and moving-shot technique. Contrast-enhanced ultrasonography (CEUS) was used to guide the supplementary ablation. Follow-ups were performed at 1, 3, 6 and 12 months. The rates of supplementary ablation, initial ablation ratio (IAR), the rates of complete ablation (CAR), treatment effects and complications between the two groups were compared.

RESULTS

The group B had larger treated nodules (10.2ml vs 6.4ml, <0.001) than group A, while group B had a lower rate of supplementary ablation (21.6% vs 75.4%, <0.001), especially in the BTNs with craniocaudal diameters ≥30mm (22.0% vs 100%, <0.001). With the assistance of supplementary ablation, both groups achieved similar IAR (100% vs 100%, =0.372) and CAR (94.7% vs 94.1%, =1.000). Two groups showed similar VRRs at 12-month follow-up (77.9% vs 77.5%, =0.894) and similar rates of complications (3.5% vs 2.0%, =1.000).

CONCLUSIONS

Needle placement using the multiple insertion points with a novel parallel overlapping mode would be easier to achieve complete ablation with less supplementary ablation, especially in large nodules.