Ultrasound-Guided Radiofrequency Ablation of Locally Recurrent Thyroid Carcinoma.

Introduction: We aimed to evaluate the effectiveness and safety of radiofrequency ablation (RFA) for non-surgical treatment of locally recurrent thyroid cancers, in both well-differentiated and medullary thyroid carcinomas (DTC and MTC) that are not amenable to traditional treatments.

Methods: We conducted a retrospective review of 48 patients with 103 recurrent tumors (81 DTC, 22 MTC) who underwent ultrasound-guided RFA. Patients were followed for 12-37 months to observe the outcomes and complications.

Results: 64 tumors (62.1%) completely disappeared at the last follow-up visit with 61 (59.2%) being resolved within 12 months. Technical success (volume reduction ratio (VRR) > 50%) was 96% (n = 99) in all tumors. The mean largest diameter of treated tumors decreased from 11.2 ± 5.3 to 2.4 ± 3.4 mm (p value < 0.001), and the mean volume decreased from 501.0 ± 807.0 to 41.6 ± 97.1 mm at the last follow-up (mean VRR = 91%). Our patients had a 77.1% recurrence-free survival rate (11 recurrences, 7 DTC, 4 MTC), with an overall mean recurrence-free survival time of 34.6 months (95% confidence interval, 30.0-39.1). We observed 3 cases with complications (voice changes in DTC patients) that completely resolved during follow-ups.

Conclusion: RFA is a safe and effective alternative to repetitive surgeries in recurrent loco-regional DTCs as well as MTCs.

Level Of Evidence: Level 3, Non-randomized controlled cohort/follow-up study.