Objective: To evaluate the long-term efficacy and safety of ultrasound-guided radiofrequency ablation (RFA) for treating locally recurrent papillary thyroid cancer (PTC).
Methods: This retrospective study involved 32 patients with pathologically confirmed locally recurrent PTC. The ablation zone was assessed by contrast-enhanced ultrasound (CEUS) after RFA. At baseline, 6 and 12 months and every 6 months or 12 months thereafter, the following results were recorded: recurrence rate, largest diameter, volume, volume reduction rate (VRR) of recurrent lesions, serum thyroglobulin (Tg) level and complications.
Results: 58 recurrent lesions in 32 patients were successfully ablated with RFA. The mean follow-up time was 73.19 ± 12.68 months (range, 60 to 98 months). At the last follow-up, almost all ablated lesions disappeared completely, and only one lesion showed scar-like changes. Nine (28.13%) patients developed new locally recurrent tumors; they were successfully treated with repeat RFA sessions. No new recurrent lesions were found during the follow-up. The largest diameter and volume of recurrent lesions decreased from 13.71 ± 6.48 mm and 520.43 ± 627.85 mm3 to 0 each at the end of observation period (p < .001). The average VRRs at 6, 12, 24, 36, 48, 60 months and last follow-up after RFA were 54.17%, 72.90%, 82.28%, 89.30%, 92.57%, 96.60%, 96.88%, 98.14% and 100% respectively. The median of serum Tg level was decreased from 1.48 ng/mL to 0.00 ng/mL (p < .05). No complications were reported during the follow-up.
Conclusions: US-guided RFA is an effective and safe option for treating locally recurrent PTC in selected patients, with favorable long-term outcomes.
Keywords: locally recurrent thyroid cancer; Ultrasonography; papillary thyroid cancer; radiofrequency ablation; thermal ablation.