Differentiated Thyroid Cancer - Episode 2
Expert perspectives on the broad management of differentiated thyroid cancer, including surgery, radiation treatment, and systemic therapy.
Lori Wirth, MD: Maybe you could describe for us what the typical thyroid cancer diagnosis and brief course of typical treatment is for the garden variety thyroid cancer.
Bryan McIver, MD: Most thyroid cancer presents as a lump in the neck, and that lump is often something that is felt on a routine physical exam. Sometimes it’s picked up on a scan done for other reasons. For example, if somebody gets their carotid artery scanned and the lump in the thyroid gland is found by accident. Occasionally, of course, the disease is found having already spread, and so sometimes a lump on the side of the neck is found and it turns out to be a lymph node involving that cancer. The typical course of treatment is to diagnose and confirm that it is cancer using a biopsy, typically a fine needle biopsy under ultrasound guidance. That biopsy leads to the diagnosis and that leads to a surgical treatment.
The most common surgery is to remove either part or all of the thyroid gland and some of the surrounding lymph nodes. Then, for patients with more advanced disease, with more aggressive disease, additional treatment with things like radioactive iodine is commonly used, and then treatment, as well, with thyroid hormone. When I think about cancer, I think about 3 main ways to treat cancer: surgery to remove it, radiation treatment to burn it, and chemotherapy to poison it. We use that same technique in thyroid cancer. We remove it surgically, we use radioactive iodine as our primary radiation therapy, and we use chemotherapy in the form of thyroid hormone. This is done because thyroid hormone in a slightly higher dose than the body expects to see can suppress the growth of thyroid cancer, and actually, in some cases, prevent it from recurring in the future. It’s important for us to think about it in those 3 modalities.
Lori Wirth, MD: Then, of course, there is a subset of differentiated thyroid cancer that recurs despite those 3 modalities of treatment, and that’s really what the program today is focused on, a more advanced differentiated thyroid cancer. There are some cancers that just have a more aggressive biology that will, despite having surgery, thyrotomy suppression, and radioactive iodine, still come back. Generally, those are considered radioactive iodine-refractory differentiated thyroid cancers. That’s really what we’re talking about today. I’m a medical oncologist. When I think of chemotherapy, I don’t think of levothyroxine so much as IV [intravenous] chemotherapy, or oral multikinase targeted therapies, or other cancer drugs that we use. They are gene-specific therapies that have a role in some subset of thyroid cancers. Bryan, of course, you are an endocrinologist, so our specialties are a little bit different. What do you think of in terms of the general role for the endocrinologist in taking care of patients with more advanced radioactive iodine-refractory differentiated thyroid cancer, and the role with the patient, and the role with the other physician team members taking care of those patients?
Bryan McIver, MD: That’s a really important question, Lori, for us to address. When I think about thyroid cancer when I first trained 25 years ago, we didn’t have the options for these more advanced targeted kinase inhibitors and other true chemotherapies. We were really restricted to surgery, radioactive iodine, and thyroid hormone. I learned during my career to care for patients from diagnosis all the way through to the end of the journey, and unfortunately sometimes that journey was the end of life because the cancer could actually kill people. It’s not a good cancer—there’s no such thing as good cancer—but certainly thyroid cancer is not always the rosy picture that people paint. A significant minority of our patients do get recurrences that we can’t control through these traditional means, or get disease that have spread, and they require more advanced therapy.
The most amazing thing during the last 10 years has been the development of so many new chemotherapy drugs, typically taken by mouth, often very effective at suppressing the cancer growth, sometimes for years and even longer. The endocrinologist has to learn to think like an oncologist and begin to recognize that some patients need systemic therapy, and then either learn how to treat those patients with those systemic therapies, or work in partnership with a medical oncologist who is used to using these drugs. I always think that a medical oncologist’s skillset is poisoning people without killing them. At the end of the day, we use these poisons, they’re going to have side effects and they’re going to have issues, but they can be highly effective in controlling this disease for which we’ve otherwise run out of options. My job is to recognize when it’s time to bring in those other skillsets. I do that with surgeons because I don’t operate. I do it with the radiation doctors because I don’t administer the radioactive iodine. I do it with medical oncology colleagues because I don’t prescribe chemo [chemotherapy]. Some people just say that I don’t do anything, which is actually accurate.
Lori Wirth, MD: Bryan, I’m curious, when you share a patient with a medical oncologist, what kind of a working relationship do you tend to have with a medical oncologist, as well as with the individual patient?
Bryan McIver, MD: I think the best way to describe the relationship I have with my medical oncology team is one of mutual respect. We both recognize that we have distinct skillsets, and we can bring those skillsets to bare to help manage the patient. I understand the cancer and I understand how to manage the early stages of that journey for this patient. Often by the time they’re coming to need chemotherapy and advanced treatments, I’ve known this patient for years, and what I don’t do is then abandon them and just send them off to a medical oncologist. We work together in a multidisciplinary clinic where we see the patients together. Once a decision is made to initiate therapy, we involve our pharmacist, who is an important team member to help understand side effect management and dose management. My medical oncology colleague does all of the difficult work of modulating the dose and getting patients to tolerate the drugs effectively, and then we jointly follow that patient in our multidisciplinary setting to review the scans, review the tumor markers, and ensure that thyroid hormone levels are appropriately managed, and that’s an ongoing relationship again for the duration of the journey.
Lori Wirth, MD: I really like your answer, because if I had been asked that question, I would have answered it in a very similar way except from the medical oncologist point of view. The other reason I really liked the answer is that I think you captured very nicely how helpful it is to have a really robust multidisciplinary team taking care of patients with advanced iodine-refractory thyroid cancer.
Transcript edited for clarity.