US Surgeons Embrace Radiofrequency Ablation for Thyroid Nodule Treatment

Jennifer Hong Kuo, MD

Radiofrequency ablation (RFA) is slowly being adopted in the United States (US) after years of success in Asia and Europe.¹ According to Jennifer Hong Kuo, MD, there is little research about outcomes for patients who undergo RFA in the US, leaving a few unanswered questions.

Prior to the introduction of RFA, the standard of care was thyroidectomy for both malignant and benign thyroid nodules. With thyroidectomy, there is a high likeliness that patients will need a thyroid hormone supplement post-surgery. For some patients with thyroid nodules, RFA may be a more attractive option because it preserves the function of the thyroid, according to Kuo.

In an interview with Targeted Oncology™, Kuo, director of the Interventional Endocrinology Program, program director of the Endocrine Surgery Fellowship Program, and the director of the Endocrine Surgery Research Program at Columbia University Irving Medical Center, discussed the use of RFA to treat thyroid nodules and how research from Columbia University will guide further research around this topic.

Targeted Oncology: Can you talk about RFA and how you are researching this modality for the treatment of thyroid nodules?

Kuo: RFA is 1 of several thermal ablative techniques that have emerged in the last couple of decades for use in managing thyroid nodules in a non-surgical manner. It was pioneered first to address benign thyroid nodules for patients who were not comfortable with the idea of removing, part of a healthy gland, especially when it wasn't cancer, only to replace it with some medication. Our institution was 1 of the first programs to get started and informally offer this to patients. But at that time, because it was so new here in the United States, we didn't have a lot of data on the outcomes for patients, and every country has a different patient population. Even though we have robust data on the international scene, I think it’s important to see if we could achieve the same outcomes here in the United States with our patient population.

I received a grant that focused on 3 different specific aims or questions. We also wanted to look at areas where there wasn't any evidence, even on the international scene. The first question was looking at clinical outcomes of RFA for treatment of patients with small papillary thyroid microcarcinomas. The second question was looking at indeterminate thyroid nodules. When we do a biopsy, about a third of thyroid nodules in this country are neither obviously cancer or obviously benign, and fall into this gray zone. We have been using molecular profiling looking at genetic signatures of these thyroid nodules to help us refine our estimate of cancer risk. We use these tests widely here in the United States, but they are not used as widely internationally. There's absolutely no data on those types of nodules with RFA.

Our research is looking specifically at RFA of 3 nodules that have been molecularly profiled and classified to be benign. The third aim was an evaluation of those patients with benign thyroid nodules who had undergone treatment with surgery vs those who undergo treatment with RFA, and looking at quality-of-life measures after treatment.

What is known about the safety and efficacy of this modality?

Even though RFA is new to the space of thyroid nodules, it's a technology that's been around for many years. We've been using it primarily for metastatic lesions in the liver and in the bone, and there, we know that it works well and it's generally safe. The problem is the power. Those are much larger tumors. It's a different tissue content, so the amount of energy that we use in those settings is much higher. When treating smaller thyroid nodules in a much smaller space, like the neck where there's also a bunch of critical structures nearby that we do not want to injure with the thermal ablation, a few modifications are necessary to the generator systems to make it more appropriate and allow for lesser energy settings.

It is important to note that it is still a procedure, and there are still some complications that can happen, but we are able to achieve pretty significant volume reduction of these thyroid nodules with these thermal ablative techniques, on the order of an average about 80% volume reduction at 1-year. So it's not immediate, it does occur over time, but it significant. One thing that is 1 of the biggest draws for these procedures in the US is that the risk for needing thyroid hormone after these procedures is almost 0%. This appeals to patients who are not comfortable with removing a perfectly healthy gland, only to replace its function with the pill.

How do you think this RFA compares with traditional surgery for removing thyroid nodules?

Both options are safe for the treatment of thyroid nodules, and both options have their advantages and disadvantages. It's really important when you see a patient who may be eligible for both procedures to kind of counsel what the expected outcomes are going to be and make sure that what you can offer with either procedure aligns with their priorities. Surgery is still the only treatment option that is going to definitively take care of a thyroid nodule, such that you never have to worry about it again, whether it grows or whether it changes into anything. It comes out and it's gone. Obviously, some of the disadvantages are that it is a procedure and the patients will have a scar from that. We can't just remove nodules themselves, we only have the option of removing half the gland or the whole thing. Therefore, even those patients who only remove half of the thyroid gland have a 25% to 30% chance that over their lifetime, the remaining half is going to be insufficient in producing all the thyroid hormones that they require. They may eventually need thyroid hormone supplementation.

In contrast, with radiofrequency ablation or any of these other ablative techniques, the goal there is not complete obliteration or complete disappearance of thyroid nodule. The goal should be volume reduction. Volume reduction means a much smaller nodule, but still a nodule is still going to have thyroid cells there. With the right blood supply and with the right stimulation, we can see regrowth of those cells. It happens about 34% of the time. Also, it doesn't necessarily mean that the nodule is going to grow back to its original size, it just means that it can. If a patient chooses to go the ablation route, then they are still committing to further management of that thyroid nodule. At the very least, further management will include continued ultrasound surveillance of that nodule, but it also may mean additional biopsies or additional procedures down the line. The biggest advantage of RFA is the thyroid hormone preservation, which is a big priority for a lot of patients.

_REFERENCES:

_{1. Kuo J, McManus C, Lee JA. Analyzing the adoption of radiofrequency ablation of thyroid nodules using the diffusion of innovations theory: understanding where we are in the United States. Ultrasonography. 2022 Jan;41(1):25-33. doi:10.14366/usg.21117.}