Long-term results of radiofrequency ablation for locally recurrent papillary thyroid carcinoma

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 mm(3) 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.