Differentiated Thyroid Cancer: Risk Stratification

Transcript: Johannes (Jan) Smit, MD, PhD: There is an evolving and ongoing debate on the optimal treatment of patients with low-risk or intermediate-risk thyroid cancer. In the past, we tended to advise a total thyroidectomy and radioactive iodine ablation for all patients with thyroid cancer. Now we are starting to learn that this extensive treatment might not be necessary in all patients with thyroid cancer, especially in patients with low-risk or intermediate-risk thyroid cancer. There is a tendency to restrict surgery to hemithyroidectomy, at least in patients with intrathyroidal thyroid cancer without vascular invasion, distant metastasis, or capsular invasion. For those patients, we will not perform radioactive iodine ablation. Whereas for patients who undergo total thyroidectomy, we tend to restrict the activities of radioactive iodides that we use to treat those patients with lower activities.

There is an ongoing trial to determine whether radioactive iodine ablation is beneficial in low-risk patients at all. So it’s an evolving debate and an evolving question: What would be the optimal treatment? But the general trend is that we are treating patients less extensively than we did in the past. On the other hand, we do not have convincing hard-outcome trials. So the ultimate answer is not there yet.

The goal of therapy in low-risk and intermediate-risk patients is the same as it is in all patients with a disorder: to improve quality of life or to maintain quality of life. The meaning of quality of life can differ for any patient, so that’s a very important point. But since those patients are very unlikely to die from thyroid cancer, I believe that one of the most important goals of treatment is to avoid overtreatment and overdiagnosis to maintain quality of life.

Eric J. Sherman, MD: Right now, for high-risk patients, we just give radioactive iodine. That’s 1 clear area in which radioactive iodine is still being used. For low-risk and intermediate-risk patients, radioactive iodine use is being pushed away more and more. We are still trying to figure out how much of an extra benefit it gives. We have just completed a randomized study called ASTRA in which we tried to give selumetinib in addition to radioactive iodine versus a placebo to see if that would lead to a greater benefit for patients. The study came back negative, but when you look at some of the reasons why it came back negative, it does suggest that patients may benefit in this situation.

One of the big problems with compliance, and I think this is an issue that we have with all oral drugs, is that physicians don’t know exactly how to treat the side effects of drugs that they’re not used to using. We didn’t run into problems with patients taking a MEK inhibitor, but we’ve done multiple studies with a MEK inhibitor.

It’s the same thing we see with lenvatinib, sorafenib, or these other drugs. So there still may be some benefit with more intensive treatment for high-risk patients. But I think this is still more of a study question. Right now, it’s really just about using radioactive iodine.

The goal of therapy is to try to decrease recurrence rates. We like to think that we’re also trying to improve survival, but it’s hard to show an improvement in survival in thyroid cancer right after surgery, because patients can live for quite a long period of time. So we’re hoping that a decrease in recurrence rates may eventually lead to an improvement in survival, but that’s something that’s a bit more difficult to show.

Transcript Edited for Clarity