What is the comparison between thyroid artery embolization and radiofrequency ablation (RFA) for treating thyroid nodules?

Radiofrequency Ablation is the Established Standard for Thyroid Nodules

For thyroid nodules, radiofrequency ablation (RFA) is the primary thermal ablation technique with the most robust evidence, while thyroid artery embolization is not a standard treatment modality for thyroid nodules. The 2025 Chinese guidelines explicitly state that RFA and microwave ablation (MWA) are the most widely used techniques for thyroid nodule ablation, achieving similar clinical results in most studies 1.

Primary Treatment Modality: Radiofrequency Ablation

RFA should be considered first-line treatment for benign thyroid nodules when surgery is contraindicated or refused, particularly for patients with:

• Solid nodules or cystic nodules with ≥10% solid composition causing compression symptoms, cosmetic concerns, or anxiety 2
• Autonomously functioning thyroid nodules 2, 3
• Recurrent nodules after chemical ablation 2

Technical Advantages of RFA

The 2025 guidelines note that RFA electrodes are sharp and facilitate easy puncturing 1. The technique achieves:

• 100% technical success rate in treating T1a-stage papillary thyroid carcinomas (PTCs) located in the isthmus 1
• Volume reduction from 5.4 mL to 0.4 mL at 12-month follow-up for benign nodules 4
• Significantly lower complication rates (1.0%) compared to surgery (6.0%) 4
• Preservation of thyroid function with 0% hypothyroidism after RFA versus 71.5% after surgery 4

Microwave Ablation as Alternative

MWA is typically recommended for patients with hyper-vascular nodules due to its strong vascular coagulation ability 1. The choice between MWA and RFA is based on:

• Nodule vascularity (MWA preferred for highly vascularized tumors) 1
• Physician preference and available equipment 1
• Similar clinical outcomes in most comparative studies 1

MWA-Specific Evidence

A multicenter study of 775 T1-stage PTC patients showed comparable 5-year progression-free survival rates between MWA (77.2%) and surgical resection (83.1%), with MWA resulting in fewer complications 1.

Thyroid Artery Embolization: Not Standard Practice

Thyroid artery embolization is not mentioned in any major thyroid nodule treatment guidelines 1, 2. The evidence base focuses exclusively on thermal ablation techniques (RFA, MWA, laser ablation, and HIFU) for thyroid nodules. Embolization techniques are established for hepatocellular carcinoma (transarterial chemoembolization) 1, but this approach has not been validated or adopted for thyroid pathology.

Patient Selection Algorithm

Step 1: Confirm Diagnosis

• All patients must undergo fine-needle aspiration biopsy (FNAB) before thermal ablation to confirm pathological diagnosis 2
• Perform thyroid function tests and calcitonin measurements 1

Step 2: Assess Nodule Characteristics

• Use ultrasound as the routine evaluation method 2
• Apply contrast-enhanced ultrasound (CEUS) to evaluate blood supply 2
• If hyper-vascular nodule identified, prefer MWA over RFA 1

Step 3: Select Appropriate Technique

• RFA for most benign nodules and select malignant cases 1, 2
• MWA for hyper-vascular nodules 1
• Laser ablation reserved for difficult locations requiring multiple fiber positioning 1
• HIFU has limited application due to longer procedure time, more pain, and less established efficacy 1

Procedural Standards

The 2025 guidelines establish specific technical requirements:

• Local anesthesia with 1-2% lidocaine 1, 2
• Transisthmic approach preferred for needle insertion 1
• Hydrodissection technique to separate ablation zone from vital structures 1
• Moving-shot and/or fixed electrode technique as standard 1
• Immediate post-ablation CEUS assessment to confirm complete ablation 1, 2

Outcomes and Follow-Up

Benign Nodules

• Complication rate: 1.7-3.5% across multiple studies 1
• Fewer hospitalization days (2.1 vs 6.6 days) compared to surgery 4
• Regular follow-up required to monitor volume reduction rate (VRR), symptom improvement, and thyroid function 1

Malignant Nodules (T1-stage PTC)

• Disease progression rate: 1.7-4.3% at 18-25 months post-ablation 1
• Recurrence rate <2% for T1a-stage PTCs at 20 months 1
• TSH suppression therapy required post-ablation, with target TSH based on initial recurrence risk 1

Critical Pitfalls to Avoid

• Never proceed without pathological confirmation via FNAB 2
• Do not use thermal ablation for nodules with confirmed aggressive histology requiring comprehensive surgical management 1
• Avoid inadequate hydrodissection when nodules are near the "dangerous triangle" (recurrent laryngeal nerve, blood vessels) 5
• Do not skip CEUS post-ablation assessment, as incomplete ablation requires immediate re-treatment 1
• Recognize that laser ablation and HIFU have limited thermal efficiency and less clinical application than RFA/MWA 1