RFA versus Microwave Ablation

How do the methods differ?

Radiofrequency ablation (RFA) uses an electrode to generate heat within a nodule. Microwave ablation (MWA) delivers electromagnetic energy through an antenna. Both are guided by ultrasound.

A clinician may consider ablation for a benign nodule that causes pressure or cosmetic concerns. Ultrasound, biopsy findings, and the nodule’s position help determine whether it is suitable. The goal is to shrink treated tissue while preserving surrounding thyroid tissue.

Neither method removes the entire nodule for a pathologist to examine. Both need follow-up, and either may require another treatment. See the RFA patient guide for a fuller explanation of evaluation and recovery.

The study Dr. Guttler selected

A European Radiology study by Fung, Luk, and Lang was published online in September 2025 and appeared in the 2026 volume. Researchers reviewed 208 predominantly solid benign nodules: 142 treated with RFA and 66 with MWA. Each received one session, with at least 12 months of follow-up.

After matching groups for characteristics including nodule size, overall shrinkage at 12 months was similar. For nodules at least 3.5 centimeters across, the MWA group had greater average shrinkage at 12 months. In a separate group with volumes of at least 20 milliliters, the advantage was statistically clear at 6 months, but not at 12 months.

This was a retrospective comparison, not a randomized trial. The size-based groups were small, and greater shrinkage did not establish better pressure or cosmetic symptom relief. The study excluded cancers and cannot compare long-term cancer control or the results of repeated treatment. Read the original study.

Other evidence and safety

A separate randomized trial published in Radiology in 2024 assigned 152 participants to RFA or MWA and followed them for at least 2 years. Mean nodule-volume reduction at 2 years was 83% with RFA and 80% with MWA. MWA met the trial’s predefined criterion for not being meaningfully worse at shrinking nodules.

That does not prove equal safety. Voice changes occurred in 5 of 76 MWA participants and 1 of 76 RFA participants. The difference was not statistically conclusive, and the authors called for a larger study to compare safety. These figures describe this trial, not every clinician’s practice. Read the randomized trial.

Professional guidance also considers patient selection and training. The 2020 European Thyroid Association guideline favored RFA and laser based on the evidence then available, placing MWA second-line. The later studies add evidence; they do not automatically replace a clinician’s assessment or establish a universal winner.

Dr. Guttler’s perspective

In the comments he submitted with the study, Dr. Guttler highlights how electrode movement and the area heated by an antenna may affect treatment of larger nodules. He also states, “I have no experience with MWA”. His comments offer an RFA clinician’s perspective rather than a report of his own microwave procedures.

The area a device heats is only one consideration. Ask how the clinician balances nodule shrinkage with protecting nearby structures, and why the proposed method fits your findings.

Questions to ask a clinician

• How certain are we that the nodule is benign?
• Would monitoring, ethanol ablation, or surgery fit better?
• What result is realistic for this nodule’s size and location?
• How much experience do you have with this technique?
• What are your complication rates and follow-up plan?
• Could I need more than one treatment, and what would it cost?