What is the preferred treatment for benign thyroid disease, comparing Radiofrequency Ablation (RFA) and Microwave Ablation (MWA) to surgery and thyroid artery embolization?

Thermal Ablation (RFA/MWA) is the Preferred First-Line Treatment for Benign Thyroid Nodules Over Surgery

The American College of Surgeons recommends thermal ablation as the first-line treatment for symptomatic benign thyroid nodules, offering comparable efficacy with superior safety, preservation of thyroid function, and shorter recovery times compared to surgery. 1, 2

Treatment Selection Algorithm

When to Choose Thermal Ablation (RFA or MWA) Over Surgery

Thermal ablation should be the default choice for patients meeting these criteria:

• Solid or predominantly solid benign nodules (≥10% solid component) with maximal diameter ≥2 cm 3, 2
• Nodules causing compressive symptoms, cosmetic concerns, or anxiety 1, 2
• Patients with significant surgical comorbidities or refusing surgery 2
• Recurrent nodules after chemical ablation 3

Critical prerequisite: All patients must undergo fine-needle aspiration biopsy (FNAB) to confirm benign pathology before thermal ablation—this is non-negotiable. 3, 1, 2

When Surgery Remains Indicated

Surgery should be reserved for specific scenarios:

• Nodules with indeterminate or suspicious cytology requiring definitive histologic diagnosis 2
• Patients preferring definitive single-intervention treatment 2
• Absolute contraindications to thermal ablation exist (see below) 2

Comparative Efficacy: RFA vs MWA vs Surgery

RFA and MWA Show Equivalent Efficacy

The most recent high-quality randomized controlled trial (2024) demonstrated that MWA is noninferior to RFA, with comparable volume reduction rates at 6 months (mean difference -5.6%) and 2 years (mean difference -2.4%). 4 Both techniques achieved 91% vs 86% technique efficacy rates respectively (P=0.40). 4

However, a 2017 multicenter prospective study of 1,252 patients found that RFA achieved significantly better volume reduction ratios than MWA at 6 months and later follow-up, though both were safe and effective. 5 A 2017 propensity-matched study of 204 patients found no significant differences between RFA and MWA at 6 and 12 months. 6

Given the mixed evidence, either RFA or MWA can be selected based on institutional expertise and equipment availability, as both achieve 50-80% volume reduction with comparable safety profiles. 2

Thermal Ablation Demonstrates Clear Superiority Over Surgery

A 2015 comparative study of 400 patients showed thermal ablation's advantages:

• Significantly fewer complications: 1.0% vs 6.0% (P=0.002) 7
• Preservation of thyroid function: 0% hypothyroidism after RFA vs 71.5% after surgery 7
• Fewer residual nodules: 2.9% vs 11.9% (P=0.004) 7
• Shorter hospitalization: 2.1 days vs 6.6 days (P<0.001) 7
• Comparable volume reduction: Nodules decreased from 5.4 to 0.4 mL at 12 months 7

Safety Considerations

Absolute Contraindications to Thermal Ablation

Do not proceed with thermal ablation if:

• Severe bleeding tendency exists 3, 2
• Severe cardiopulmonary insufficiency or inability to cooperate with the procedure 3, 2
• Contralateral vocal cord paralysis on the treatment side is present 3, 2

Relative Contraindications

Exercise caution in:

• Pregnant and lactating women 3, 2

Complication Rates

The most common major complication is voice change, occurring in 6.6% with MWA and 1.3% with RFA (P=0.21), though most patients recover spontaneously. 4 Overall major complication rates are 4.78% for RFA and 6.63% for MWA with no statistically significant difference. 5

Critical Technical Requirements

Hydrodissection technique must be employed to protect the recurrent laryngeal nerve, trachea, esophagus, and major vessels—this is a strong recommendation based on high-quality evidence. 1 Use local anesthesia with 1-2% lidocaine and prefer the transisthmic needle insertion approach. 1

Thyroid Artery Embolization: Not Recommended as Primary Treatment

Thyroid artery embolization is not mentioned in current guidelines as a first-line or alternative treatment for benign thyroid nodules. The evidence base supports thermal ablation and surgery as the established treatment modalities. 3, 1, 2

Common Pitfalls to Avoid

• Never proceed without confirmed benign cytology: Malignancy must be excluded via FNAB before considering ablation. 1, 2
• Do not overlook hydrodissection: This is essential to prevent nerve injury. 1
• Do not use thermal ablation for cystic nodules with <10% solid composition: Chemical ablation is more appropriate for predominantly cystic lesions. 3

Post-Treatment Monitoring

Follow-up schedule:

• Initial assessment at 1 month 1
• Subsequent evaluations at 3,6, and 12 months during the first year 1
• Annual ultrasound and symptom evaluation after 12 months 1
• Monitor volume reduction rate (VRR) as the primary efficacy endpoint 1