Purpose:
To evaluate the effects of radioactive iodine (RAI) ablation after radiofrequency ablation (RFA) in patients with recurrent papillary thyroid carcinoma (PTC).

Material and methods:
We conducted a retrospective cohort study involving 60 patients with documented cervical lymph node (LN) recurrent PTC. All RFA procedures were performed using the “pulling-back, moving-shot” approach under local anaesthesia. LN volume reduction ratio (VRR), thyroglobulin, and complications were analysed 6 and 12 months after RFA. This study comprised two distinct groups of patients: one group that received a combination of RFA and RAI ablation, and another group that underwent RFA alone (30 cases in each group).

Results:
The mean age of patients was 39.8 ± 10.5 years, 68% of whom were women. VRR of LNs was significant at 6 months and 12 months after RFA (87.4% and 91.9%, respectively, p < 0.001). Serum thyroglobulin level decreased after 12 months (2.7 ± 5.9 to 0.6 ± 1.8, p = 0.021). Post-RFA complication was noted in one patient with transient hoarseness. Ten new recurrent LNs were reported in 9 patients (15%) during follow-up. No benefit was detected for the RAI treatment at the end of 12 months of follow-up in terms of structural or biochemical recurrence. Based on the non-randomised retrospective study design, this comparison is descriptive in nature and cannot be used to make any causal inference regarding the effectiveness of adjuvant RAI.

Conclusions:
RFA has been shown to be effective in achieving volume reduction with a high success rate of 97% and with minimal complications. There was no additional benefit of adjuvant RAI. However, this result cannot be used to make any inference regarding the effectiveness of RAI due to confounding by indication. A prospective randomised trial is needed.