Approaches to Monitoring Patients With Differentiated Thyroid Cancer

Lori Wirth, MD: One of the things that I say to patients while we’re doing active surveillance is, “You’re still on treatment for your thyroid cancer with TSH [thyrotropin] suppression.” Let’s use this as a segue to talking a little about active surveillance. For example, how often do you perform tumor marker testing and imaging? And then how do you make the difficult decision about when to start a systemic therapy for somebody with iodine-refractory disease? Marcia?

Marcia Brose, MD, PhD, FASCO: The new phrase I’m using for doing this, only for reimbursement purposes with my providers, is I’m calling it disease monitoring. It’s a new term because every time I put the word “surveillance” in my note, they turn down all of my scans, and I have to call for a peer-to-peer review. Anyway, the idea is that we have a patient now, and we’re not even talking about biomarker-only disease. I’m thinking more about the patients who now actually have measurable disease. So, I can see a nodule on their lungs or on lymph nodes that is clearly abnormal and I can measure it. There are different flavors of this, which is beautifully illustrated in Mike Tuttle, [MD]’s paper of the different curves of the way this can go.

There are people who will have biomarker disease only or very small 1-mm nodules, and they won’t change. Those people I usually follow with biomarkers and maybe a CT scan every 6 months, just to make sure nothing’s changing. Usually if they’re RAI [radioactive iodine]-refractory, I don’t have the interval go longer than 6 months. Because they’re RAI-refractory, sometimes that can change, and I don’t usually want to give more than a 6-month head start if that disease starts to grow more quickly. Then there are patients who are starting to grow, they might have several nodules that are all below 1.5 cm, the tumor burden overall is mild to moderate, no risk at all of symptoms. In those cases, if things are starting to pick up the pace, maybe move them from every 6 months to every 4 months or every 3 months. And I do that as a risk-stratified approach, where my scan interval is mirroring how concerned I am that they’re going to have either a nodule that I already know is growing a little more quickly, or that the nodules are in a bad location where they can cause symptoms.

This by the way takes out all the people who are symptomatic because they would’ve started on treatment immediately, because I treat for symptoms. And hopefully I will have had the opportunity to do this disease monitoring because they will have been referred to me before they get symptoms. So, a lot of that has to do, again, with the benefit of seeing a lot of these patients. When we talk about what do we do if you’re in the community and don’t see this very often, the first choice, if at all possible, is to get the patient to a place where this is done a lot. I find that in our center we’re more likely to allow the patient to stay on disease monitoring a little longer because we understand the pace of the disease a bit better. Whereas a 1.5-cm nodule in an oncology practice that treats mostly lung cancer, that’s not going to be left alone. I might actually buy another year for that patient before they get treated.

We balance the location, the rate it’s progressing, the overall tumor burden. Of course, symptoms can’t be there at all. You try to balance all those together to say, how can we not treat this patient for as long as possible? Because the reality is that once they do start systemic treatment, they often will be on that for the rest of their lives. So, I have a conversation with the patient. Some patients really want to start right away. Some of them never want to start at all. I talk to them a little about the idea that we’re going to be doing a risk/benefit ratio here and balancing the pros and cons at all times. That’s my approach.

Transcript edited for clarity.