Thyroid Nodule Thermal Ablation

Background and indications

Thyroid nodule thermal ablation (radiofrequency - RFA, or microwave - MWA) is a minimally invasive treatment for symptomatic benign thyroid nodules. The principle is to destroy nodular tissue through heat, causing progressive volume reduction and symptom improvement (cervical discomfort, cosmetic deformity, compression).

Main indications include: symptomatic solid or mixed benign nodules (≥ 2 cm with functional or cosmetic concern), after benignity confirmation by 2 concordant FNA (Bethesda II). Thermal ablation is an alternative to surgery (lobectomy, thyroidectomy) that preserves thyroid function.

Pre-procedure assessment

Assessment includes 2 benign FNA (Bethesda II), thyroid ultrasound with precise nodule volume measurement, complete thyroid panel (TSH, T4, anti-TPO antibodies), and ENT vocal cord examination. The nodule must be distant from the recurrent laryngeal nerve, trachea, and carotid vessels.

Procedure

Under local anesthesia and light sedation, a radiofrequency electrode (18G, adjustable active tip) or microwave antenna is inserted into the nodule under ultrasound guidance. The "moving shot" technique is used: the electrode is progressively moved through the nodule to treat all tissue, from deep to superficial. Temperature reaches 60-100°C, causing tissue coagulation. Hydrodissection (cold saline injection) protects adjacent critical structures. The procedure takes 30 to 60 minutes depending on nodule size.

Results and scientific evidence

Radiofrequency thermal ablation achieves 50-80% nodule volume reduction at 12 months, with significant improvement of compressive and cosmetic symptoms (Baek et al., Radiology, 2012; DOI: 10.1148/radiol.12111405). Thyroid function preservation rate exceeds 95%, unlike surgery which causes permanent hypothyroidism in 30-100% of cases depending on extent.

The 2024 Korean Society of Thyroid Radiology guidelines and European recommendations (EU-TIRADS) support this approach as an alternative to surgery for symptomatic benign nodules.

Risks and complications

Local pain during and after the procedure (20-40%, controlled with analgesics), cervical hematoma (< 3%), transient voice change from recurrent nerve involvement (1-2%, complete recovery in > 90% of cases). Major complications are rare: permanent recurrent nerve injury (< 0.5%), skin burn (< 0.5%).

Recovery

Return to normal activities the following day. Moderate cervical swelling may persist 2-3 days. Nodule reduction is progressive over 6-12 months. Ultrasound follow-up at 1, 6, and 12 months. A second session may be offered if reduction is insufficient.

Practical information

The procedure is performed as an outpatient or short inpatient stay depending on the case. It is performed by an interventional radiologist specialized in thyroid pathology.