Impact of Hashimoto's thyroiditis on radiofrequency ablation for papillary thyroid micro-carcinoma: a cohort study of 391 patients.

Purpose: To assess the impact of Hashimoto's thyroiditis (HT) on radiofrequency ablation (RFA) outcomes for papillary thyroid microcarcinoma (PTMC).

Methods: A retrospective study of 391 PTMC patients treated with RFA from March 2017 to August 2020, divided by HT accompanied or not. Ablation area size, volume reduction ratio (VRR), lesion disappearance, complications, and recurrences were analyzed.

Results: 391 patients (mean age, 41.3 ± 11.2 [SD]; 317 women, 110 with HT) were evaluated. The follow-up time was 2 years. HT+ PTMC patients (Group A) exhibited larger ablation diameters at 1st and 3rd month post-RFA. In comparison, PTMC patients (Group B) had larger diameters at 1st and 3rd months but smaller at 6th months, returning to baseline around 6th month in Group B and 9th month in Group A. VRRs in Group B were greater than Group A at 3rd, 6th, 9th, 12th and 15th month, all  < 0.05). The curves revealed a slower lesion disappearance rate in A (12th) compared to B group (9th). Complication and recurrence rates were similar for both groups (4.4% and 0.8% overall, Group B vs Group A: 4.3% vs 4.6%,  = 0.905; 0.4% vs 1.8%,  = 0.192).

Conclusion: HT delays the resorption of PTMC lesions following RFA, but it does not impact the procedure's effectiveness or safety. Regardless of HT status, RFA remains a viable alternative to surgery for PTMC.