Thermal ablation of thyroid nodules

What is thermal ablation?

Microwave thermal ablation destroys the nodule from the inside, using heat. Under ultrasound guidance, a thin, continuously cooled needle is placed in the core of the nodule. Connected to a generator, it delivers microwaves that heat the tissue and burn the small vessels feeding the nodule. Deprived of blood, the nodule dies and is gradually absorbed by the body, shrinking over the following months. The thyroid gland is preserved and, in the vast majority of cases, no hormone treatment is needed afterwards.

Who is it for?

• Benign nodule, confirmed benign by two fine-needle aspirations, when it becomes bothersome: because it compresses (lump sensation in the throat, difficulty swallowing, cough) or because it shows (visible, unsightly nodule).
• Toxic nodule (hyperfunctioning, "hot nodule"), identified on scintigraphy and checked by one fine-needle aspiration: ablation is then an alternative to surgery and radioactive iodine.
• Thyroid cyst: ethanol ablation (alcohol injection), which is simpler, is offered first; thermal ablation is kept for mixed nodules and recurrences.
• Papillary microcarcinoma (under 1 cm), in selected, well-informed patients, provided that post-procedure follow-up by a multidisciplinary team is ensured: the 2025 ATA guidelines recognise percutaneous ablation as an alternative to surgery.
• Patients who categorically refuse surgery, when their nodule otherwise requires treatment.

The decision is always made in consultation, based on an ultrasound, blood tests (TSH, coagulation tests) and a review of the aspiration results.

When thermal ablation is not indicated

• Suspicious or malignant nodule (apart from selected microcarcinomas), or inconclusive aspiration.
• Nodule extending behind the breastbone, hard to reach.
• Nodule whose treatment would carry a risk of vascular injury.
• Uncorrected bleeding disorders, or pregnancy.

How does the session go?

1. Before the session: consultation, ultrasound mapping of the nodule and, if needed, stopping anticoagulants as advised by the referring doctor.
2. On the day (Thursday morning, at the Errahmane clinic – Dr Boutahar): pre-anaesthetic consultation and pre-procedure blood tests, then local anaesthesia of the skin and tissues around the thyroid. There is no general anaesthesia: the patient stays awake and talks with the team throughout.
3. Continuous hydrodissection: cold fluid is injected continuously around the thyroid. It creates a heat-insulating space that protects the recurrent laryngeal nerve (voice), the trachea and the blood vessels.
4. Ablation: the needle heats the nodule area by area under continuous ultrasound control. The session lasts about 20 to 40 minutes depending on nodule size.
5. After the session: a few hours of observation, then discharge the same day. Usual activities can resume the same day, with a few precautions.

Expected results

• The nodule shrinks gradually: the reduction is already clear between 3 and 6 months and continues up to 12 months.
• Discomfort, whether due to compression or to the appearance of the neck, eases at the same pace.
• For toxic nodules, thyroid function most often returns to normal.
• Follow-up relies on control ultrasounds at 1, 3, 6 and 12 months, then once a year.

Possible side effects

The neck may be sore or tender for the first few days; simple painkillers are enough. A small bruise or temporary swelling may occur. More rarely, the voice may change temporarily. Serious complications are exceptional.

Frequently asked questions