Initial Workup for Differentiated Thyroid Cancer

Transcript:R. Michael Tuttle, MD: Hello, and thank you for joining this OncLive Peer Exchange, an expert-based discussion of the “Multidisciplinary Perspective on Differentiated Thyroid Cancer.” Although most patients with differentiated thyroid cancer have an excellent prognosis, a subset of these patients will develop a more aggressive refractory phenotype. Fortunately, recent understanding of the molecular pathogenesis of thyroid cancer has led to exciting novel therapies for advanced disease. In this discussion, my colleagues and I will provide perspective on the latest information about how to use these therapies and the path forward to a more personalized approach for patients.

My name is Dr. Michael Tuttle, and I’m a professor of medicine for the Endocrinology Service at Memorial Sloan Kettering Cancer Center. Participating today on our distinguished panel are Dr. Marcia Brose, an associate professor at the University of Pennsylvania in Philadelphia and the director of Center for Rare Cancers and Personalized Therapy; Dr. Naifa Busaidy, an associate professor at the University of Texas MD Anderson Cancer Center and director of the Thyroid Nodule Clinic; Dr. Eric Sherman, an associate professor of medicine at Memorial Sloan Kettering Cancer Center in the Head and Neck Division of Solid Tumor Service; and Dr. Frank Worden, a professor of medicine at the University of Michigan Comprehensive Cancer Center. Thank you again for joining us. Let’s begin.

In our first section, we’re going to talk about some of that initial diagnosis and staging and risk assessment. Dr. Busaidy, just take me from the beginning. What’s the typical presentation of a patient that gets diagnosed with thyroid cancer? What’s their initial workup look like for the average patients?

Naifa Busaidy, MD, FACP, FACE: Sure. Most patients have their thyroid cancer incidentally found. Most of these patients are asymptomatic and don’t have any symptoms. So, perhaps they went to a health fair and had a carotid ultrasound, and they happen to have a thyroid nodule found. Then they see their physician and get an ultrasound of their neck. A full evaluation of the entire neck is important. You start out looking at the thyroid, and you look at the nodules. Very often about up to 65% of the population can have nodules on their thyroid found on ultrasound, so it’s important that we try and evaluate which of these nodules should be biopsied.

So, the first thing you do is the ultrasound, and you also get a blood test as a Thyroid-Stimulating Hormone (TSH). And what one is looking for is if the TSH is suppressed. Then it’s suggested that the patient may be hyperthyroid, so one may then do a radioactive iodine—an I-123 or thyroid uptake scan—to evaluate if the nodule is hot or not. If the nodule is found to be hot, the risk of that nodule being malignant is less than 1%. That may be a nodule you choose not to biopsy. It’s a rare instance where a hot nodule is truly thyroid cancer. If your TSH is normal or high, you don’t need the iodine scan.

So, what one would do is, do the ultrasound and evaluate the characteristics of the nodule. That’s one of the biggest things that’s changed in the guidelines lately, that there’s much more emphasis on, don’t just biopsy any nodule or the dominant nodule or the large nodule, but the nodules that are actually suspicious looking. One may begin with the nodule that is greater than 1 or 1.5 cm that has suspicious sonographic characteristics and biopsy those nodules. And, at the same time, one would look at the lymph nodes of the neck. If there’s many lymph nodes that may be suspicious, those may need biopsying as well. Once the fine needle aspiration (FNA) is done, then one needs to look at the site of pathology of those nodules and evaluate whether it’s malignant or not, and go down that pathway.

R. Michael Tuttle, MD: In most of the patients, once they’re diagnosed with thyroid cancer, they want to be reassured, be told that things are going to be okay. What are the features, that when you’re doing this initial evaluation, you find very reassuring? And then we’ll come back in a minute and ask Frank to say what the features that you find really worrisome are. The reassuring things? What are the features that you’re going to tell the patient, “You’re probably going to do okay with the appropriate treatment?”

Naifa Busaidy, MD, FACP, FACE: There’s certain risk factors when we evaluate the patient as to how, overall, their prognosis is, or how they’re going to do, from a thyroid cancer standpoint, from both death and recurrence. If a patient is young, under 45—that age may be changing as we relook at the data, but for now, if the patient is under 45, if they’re female, if the nodule is small—especially smaller than 4 cm—and there’s no lymph nodes that are seen on imaging preoperatively and will get to surgery later, then those are reassuring things. This is a patient who’s going to do well with simple therapy.

R. Michael Tuttle, MD: So, most of the patients we see are that sort of low-ish risk, kind of small confined to the thyroid. Frank, when you hear about the stories, these presentations of thyroid cancers, what are some of the things that make you say, “Boy, this really makes me worry? This is a patient that may actually end up needing more than just surgery and radioactive iodine.”

Frank Worden, MD: Right. So, kind of counter to what Naifa was saying: we worry about patients who are older, patients who are male, more so than the female patients, the patients who have larger tumors. Those greater than 4 cm are tumors that extend to the thyroid capsule, so that extension of the thyroid or tumor through the thyroid capsule is concerning—patients who have bulky or large cervical or other neck lymph nodes—and can extend down into the mediastinum. Those are all concerns. In addition, patients can present with metastatic disease, and so those would be the patients we’d be concerned about for the highest risk of spread.

R. Michael Tuttle, MD: Marcia, Naifa talked largely about our initial staging really revolving around the ultrasound. Are there certain features in that initial presentation that should warn us that maybe we need more staging than just the ultrasound, CTs, or looking for distant metastasis? When do you think we should look outside the neck?

Marcia S. Brose, MD, PhD: Well, I think the American Thyroid Association Guidelines are probably going to be more carefully elucidating this than I can off the top of my head. But I really do worry about patients who have the extra thyroidal extension or lymph nodes that extend outside of the lymph nodes. These are all people that are going to be at much higher risk, and they definitely should have additional staging, usually a CT scan of the chest, remembering that these patients are going to get radioactive iodine. So, when you do those stagings, you always do a non-contrast CT.

R. Michael Tuttle, MD: Naifa, where do you draw the line? We talked a lot about using ultrasound as our initial staging. When do we say we need to go that extra step? You don’t always do it. Probably most of the time we don’t. But when are you thinking about that early in this initial staging at presentation?

Naifa Busaidy, MD, FACP, FACE: I think most of these patients are going to undergo surgery, either lobectomy or total thyroidectomy. So, there’s a couple of things that help us out. One is looking at the operative report, having that conversation with the surgeon as to identifying what they saw intraoperatively. Was the thyroid cancer stuck on other organs in the neck? Were there lateral lymph nodes that were large? Were there multiple lateral lymph nodes? Looking at the staging system postoperatively, as well as having that discussion with the surgeon and reading the operative report are what will help guide me in terms of staging and figuring out the high- versus low-risk.

R. Michael Tuttle, MD: Yes. It’s really gone past just reading the path report and saying that’s what the information is. We need all that information from the surgeons.

Transcript Edited for Clarity