Ultrasound-guided radiofrequency ablation for isthmus papillary thyroid microcarcinoma: a prospective 2 years of follow-up study

To explore the safety and clinical efficacy of radiofrequency ablation (RFA) for papillary thyroid microcarcinoma (PTMC) located in the isthmus. This prospective study enrolled patients with single isthmus PTMC admitted to General Surgery Department of 983rd Hospital of Joint Logistic Support Force of PLA from 2017 to 2022. After ablation, the ultrasound and contrast-enhanced ultrasound (CEUS) were performed to follow up the outcomes at 1, 3, 6, 12, 18, and 24 months. The volume reduction rates (VRR), disappearance rates (DR), incidence of complications, recurrence, and lymph node metastasis were recorded. A total of 135 patients were enrolled in this study, including 26 men and 109 women. The average age was 41.07 +/- 13.60 years old. The average diameter of PTMC was 0.68 +/- 0.17cm. After ablation, the DRs at 1, 3, 6, 12, 18 months, and 24 months were 0.0% (0/135), 10.4% (14/135), 52.6% (71/135), 81.5% (110/135), 100% (135/135), and 100% (135/135), and the VRRs at 1, 3, 6, 12, 18 months, and 24 months were 66.18 +/- 12.57%, 82.42 +/- 12.01%, 93.33 +/- 8.70%, 98.58 +/- 3.71%, 100.00 +/- 0.00%, 100.00 +/- 0.00%. Two patients suffered recurrence of PTMC in the thyroid at 6 and 12 months after ablation, and one patient suffered cervical lymph node metastases at 18 months after ablation. No patient had serious complications, including death, hemorrhage, or thermal injury to peripheral organs. RFA was a safe and effective treatment for isthmus PTMC, which may add new choices to the treatment strategy for patients.