News > Medscape Medical News
Nancy A. Melville
September 19, 2023
With ever-expanding treatment options for the ablation of benign thyroid nodules, the American Thyroid Association (ATA) has issued an expert consensus statement that addresses the safe implementation and utilization of the techniques.
“There are no documents to date in the United States focusing primarily on the safe adoption and implementation of ablation techniques, including learning curve considerations and necessary pre-procedural skillsets,” reports the ATA task force in the consensus statement, which was published this month in Thyroid.
“Although these emerging technologies hold great promise, they are not without risk and require development of a unique skill set and environment for optimal, safe performance and consistent outcomes,” task force co-author Catherine F. Sinclair, MD, an associate professor at the Icahn School of Medicine at Mount Sinai, in New York, told Medscape Medical News.
Chemical ablation has long been utilized as a nonsurgical option for benign thyroid nodule ablation. However, the current array of treatment options has expanded with thermal ablation. Techniques such as radiofrequency ablation (RFA), laser ablation, microwave ablation, and high-intensity focused ultrasound have gained favor as minimally invasive alternatives to surgery.
Much has been published on indications and outcomes with the use of the techniques. The multidisciplinary global task force was convened to address key issues regarding safety and utilization. The report is directed toward specialists, including surgeons, endocrinologists, and interventional radiologists.
The recommendations cover three broad categories: safety considerations spanning preprocedural to postprocedural periods; necessary skill sets for optimal, safe performance with the approaches; and the expectations for success in the context of risks and benefits.
Ablation Methods Can Depend on Nodule Type
Among key issues addressed are which ablation methods are most appropriate for which types of nodules. Recommendations include chemical ablation, typically involving the injection of dehydrated ethanol in a target nodule. In solid nodules, diffusion with chemical ablation can be unpredictable, which makes it more appropriate for cystic nodules.
Thermal ablation is considered best suited for patients with compressive and/or cosmetic complaints that clearly involve a single or dominant nodule, as well as for autonomously functioning thyroid nodules that cause subclinical or overt hyperthyroidism.
While ethanol ablation is recommended as a first-line treatment for benign cystic thyroid nodules, its efficacy decreases when there is an increase of more than 20% of the solid component. In such cases, RFA or a combination of ethanol ablation and RFA may be considered, the task force recommends.
Patient Counseling ― Managing Expectations
Another key consideration in treatment with thyroid nodule ablation is managing patients’ expectations.
Patients should be advised of benefits, such as the avoidance of surgery and general anesthesia and less recovery time. Risks can include thermal or chemical injury to the recurrent laryngeal nerve and other vital structures. The task force underscores discussion of alternative options with patients.
Alternative management options to ablation, including observation, radioactive iodine for functioning nodules, and surgery, should also be discussed, and “their relative advantages and disadvantages should be presented without bias such that the patient can make an informed, individual treatment decision,” the task force recommends.
Patients should be informed that, in contrast to surgical management, the benefits of ablation are not immediate; rather, they accrue over the course of months. Reduction in nodule size within the first month is often limited.
Pain, soreness, and some swelling of the nodule and surrounding tissues are common in the first week. These symptoms usually peak in the first 3–5 days after the procedure. Importantly, patients rarely require opioid medications, and their use should be avoided, the task force recommends.
Patients also should be informed about the possibilities of nodule regrowth following ablation and the possible need for more than one ablation procedure.
“Although regrowth definitions in the literature vary, risk of regrowth after thermal ablation is 5% to 40% and increases the larger the baseline nodule volume,” the task force notes.
Of note, most studies on ablation to date have shown that thermal ablation complication rates are low. Volume reductions are typically greater than 50% 12 months post procedure.
Follow-Up
For long-term monitoring following ablation, follow-up neck ultrasound is typically recommended at 1–3 months and at 6 and 12 months post ablation to assess volume reduction, nodule appearance, nodule vascularity, and areas at risk for regrowth, the authors note.
Prolonged serial biochemical evaluation of thyroid function is only recommended in cases of hyperfunctioning thyroid nodules.
Key considerations for additional ablative sessions for nodules greater than 20 to 30 mL in volume should include a failure to achieve adequate reduction in volume, nodule regrowth in previously untreated peripheral areas, and/or persistent or new compressive symptoms.
Learning Curve
Sinclair underscored that successful thyroid nodule ablation requires skill ― and experience.
“Probably the greatest concern shared by the writing group on this statement was the potential for clinicians to start ablation practices without having an appropriate prior skill set,” she said.
“Ablation is an advanced ultrasound-guided procedure, and clinicians need to be experienced in performing neck ultrasounds and biopsies,” she added. “To consider performing ablations without this skill set is both unrealistic and dangerous.”
RFA, currently the most commonly used thermal ablation method for benign thyroid nodule ablation in the US, “has a good safety profile but can have a steep learning curve initially,” she said.
Among the most important recommendations is that for their first 20–60 ablation procedures, clinicians should consider limiting treatment to small- to medium-sized benign nodules rather than large-volume disease, Sinclair added.
“In addition, prior to starting thyroid ablation practices, clinicians should be proficient in ultrasound imaging and fine-needle biopsies and can gain valuable experience by practicing on phantoms and having expert proctoring for the first few cases,” she said.
For initial ablative cases, the task force recommends that clinicians select moderate-size (<20–30 mL), nonvascular nodules with favorable characteristics and location. The final volume reduction should be based not only on baseline nodule characteristics, such as volume and vascularity, but also on the practitioner’s skill.
Clinicians furthermore should be board certified or eligible in an appropriate medical specialty, have extensive background knowledge, and “should have clinical experience in the clinical diagnosis and treatment of thyroid nodules; neck imaging anatomy; thyroid ultrasound imaging and fine needle aspiration biopsy procedures; and ultrasound risk stratification for benign and malignant thyroid tumors,” the group recommends.
Importantly, the statement is designed to reflect a consensus opinion of the panel of experts but is not meant to serve as a formal guideline or a standard of care for the clinical practice of thermal ablation, Sinclair added.
“It is not the intent of the statement to replace individual decision-making, the wishes of the patient or family, or clinical judgment.”
The authors’ disclosures are detailed in the published report.
Thyroid. Published September 14, 2023.
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