Anand Shivnani, MD, Radiation Oncology, Baylor Scott & White talks about how thyroid cancer is on the rise.
Interview conducted by Ivanhoe Broadcast News in July 2017.
Generally speaking oncology and treatment, mostly what are you doing?
Dr. Shivnani: We’re using radiation to treat different types of cancer. So depending on the type of cancer and the patient sometimes patients will have surgery first and then they’ll have radiation afterwards. Sometimes they’ll have chemotherapy, sometimes they’ll have a combination.
So if it’s chemo then you’re working with another?
Dr. Shivnani: Correct. So I’m working with a medical oncologist which is a doctor that gives chemotherapy.
Let’s narrow in on the topic of the day which is thyroid. What are you seeing generally speaking with the thyroid? For example, Mitsy our patient it took a long time for them to figure out what was wrong with hers.
Dr. Shivnani: We’re seeing thyroid cancer in younger patients than what we typically think of when we think about cancer. Usually when we see cancer it’s often a disease we see in elderly patients. But thyroid cancer is a type of cancer that we see often in patients in their thirties, even in their twenties or younger than that. So often times these are found because a doctor or a patient notices a nodule or a lump in their neck or a patient has a scan for some other reason and they identify something in the thyroid gland that we need to biopsy.
You say that you see it in younger patients; are there studies or something you’ve been seeing that indicates this and why this is occurring?
Dr. Shivnani: Yeah we really don’t know the answer why. There was a thought that the incidence of thyroid cancer was increasing because more and more patients are undergoing scans for other reasons. And these were thought to be more incidental findings than anything else. But even when they’ve done studies to correct for that, there seems to be an increase in the incidence of thyroid cancer and we still don’t have a good explanation for why. The good news is that the cure rates are very good especially if it’s caught very early.
What are some of the thoughts or what are they looking into as being possible causes for this new trend?
Dr. Shivnani: The question that seems to be arising is, is there some environmental exposure that is predisposing patients to thyroid cancer? Usually that’s what we think about when we’re seeing an increase in incidences in younger folks.
When you say environmental exposure does that also include food?
Dr. Shivnani: Right. So diet, occupational exposures; you know patients who are exposed to radiation, and for other reasons. We often think about patients who were around in the fifties and earlier, some of those patients were exposed to radiation as children for different conditions that they used radiation for back then that they no longer use them for today. Things like acne and various sorts of things, so sometimes if someone has had exposure to radiation as a child they’re at a higher risk for getting thyroid cancer as an adult.
So what is the link between radiation and thyroid cancer?
Dr. Shivnani: Radiation in general is a useful treatment for cancer, but it in and of itself is associated with a small risk of causing cancer and so especially when children are exposed to radiation they are at risk for various types of cancer including thyroid cancer. And the thought is that it causes some mutation in the cell that later on down the road may develop into a cancer. That’s why we don’t recommend radiation to children unless it’s absolutely critical that they receive it.
Like in Mitzi’s case, she went for eight years and nobody could figure out what was wrong with her… She was treated with steroids, which she said causes a great weight gain? Was it just that she was misdiagnosed or is this typical?
Dr. Shivnani: Right. It’s typical that patients can have various symptoms and often times with the thyroid there may not be a specific symptom that clues somebody in that there’s something going on with the thyroid. Sometimes you have a patient who is quite tired and they look at other explanations before they check their thyroid. Or within the thyroid there can be fluctuations in their thyroid hormones at different times of the day. So just checking at one moment in time, you may not be able to get to a diagnosis and it may take some time to establish a diagnosis.
You could expect that there is some abnormality with the thyroid? We could have too much thyroid hormone or too little and those are different right?
Dr. Shivnani: Right, those are different, the symptoms are completely different. A lot of times we find these nodules where these thyroid cancers in patients aren’t having any symptoms whatsoever. It’s just something like I said that’s noted on a physical exam, or that’s found on a scan ordered for some other reason completely unrelated to the thyroid.
Why is the thyroid so important?
Dr. Shivnani: The thyroid regulates your body’s metabolism. When your thyroid is underactive, patients can feel tired; they can gain weight, their bodies normal metabolic processes just move more slowly. Conversely if your thyroid is overactive then the opposite can happen, your body sort of racing at a faster pace than what it’s supposed to. You may lose weight and it can cause problems with your heart and other body systems if things are functioning faster than what their supposed to be.
You can have a problem with your thyroid and it’s not cancer, correct?
Dr. Shivnani: Exactly.
And you would treat for that all the time?
Dr. Shivnani: Correct.
So you don’t know if it’s cancer until you do a biopsy?
Dr. Shivnani: Yes. So typically a doctor will get an ultrasound of the thyroid and then if they see a nodule that is big enough in size to put a needle through they will order a biopsy of that. Sometimes that biopsy will come back with a clear diagnosis of thyroid cancer and sometimes it will come back with a diagnosis of what we call atypical cells, which are cells that could be cancer but it’s not reached a level that a pathologist can formerly diagnose the cancer.
In her case I think one nodule was cancerous and the other one was sort of questionable?
Dr. Shivnani: Right.
And that’s pretty much what it was with her?
Dr. Shivnani: Yeah, correct. Sometimes if there’s a question of a diagnosis, then a surgeon will try to remove part of the thyroid and if they can confirm a diagnosis of cancer in that, then they’ll have to go back and remove the rest of the thyroid. Other times if they know that it is a diagnosis of cancer then they just go ahead and remove the entire thyroid.
Even if it’s just one lobe?
Dr. Shivnani: Correct, because if you have a cancer in one part of the thyroid there can be smaller areas of cancer in the other parts of the thyroid.
And there’s also the parathyroid which are components of the overall thyroid?
Dr. Shivnani: Those are separate glands that are near the thyroid, sometimes they’re removed at the same time as the surgery to remove the thyroid, but you need those glands as well. The surgeon doesn’t want to remove all of those glands.
How does the iodine play into the functioning of the thyroid and what happens when you take the thyroid out?
Dr. Shivnani: The thyroid needs iodine to synthesize the thyroid hormone which regulates these processes in the body, and so we take advantage of that fact after treatment. When the thyroid is removed the concern is that if there are any cancer cells left behind we want to try to destroy those cancer cells to prevent it from growing again. The other issue is that the endocrinologist which is the doctor that deals with thyroid issues are using a blood test called a thyroglobulin level to follow patients after their treatment. That has to do with how much of the hormone is produced by this tissue. The concern is that when the surgeon removes the thyroid they are literally peeling the thyroid off a bunch of normal structures in this area, like blood vessels and nerves. So when you’re taking it out there is often a little bit of thyroid tissue left behind. That can be confusing for the endocrinologist because they are trying to do this blood test to check for any thyroid but if the thyroglobulin is elevated they don’t know if it’s because of cancer cells or just because of that residual thyroid tissue. That being said, the other purpose of doing this treatment is to destroy that residual normal thyroid tissue, so that when the endocrinologist is following them, when they check the thyroglobulin level, if it goes up, there’s a strong suspicion it’s because of thyroid cancer and not because of that residual normal thyroid tissue. We’re using an isotope of iodine, which is similar to the iodine that we get in our diet in salt and so forth, to destroy any of that residual thyroid tissue as well as any residual cancer cells that may be left behind.
So what do you call it, radioactive?
Dr. Shivnani: We call it radioactive I-131 which is the specific isotope of iodine that we use. It basically comes in a pill form that patients take after some preparation beforehand and it goes to the areas where there could be any cancer cells left behind. Typically the thyroid bed where the cancer was removed, and it gets excreted in the urine so patient’s basically excrete it on their own afterwards.
So it’s useful in clearing up residuals of cancer?
Dr. Shivnani: Correct. Thyroid cancer specifically.
It’s the radioactive version of iodine?
Dr. Shivnani: Right, it has more neutrons compared to the regular iodine and when the patients take it up the body thinks it’s the normal type of iodine that you get in iodized salt. It then takes it into the thyroid tissue that’s left behind.
And that will kill it?
Dr. Shivnani: Correct.
I guess after that she had to go into isolation?
Dr. Shivnani: Right, so patients are radioactive after they get this treatment. It used to be that patients had to stay in the hospital for several days afterwards until their radioactivity decreased below a certain level that they were felt to be okay to go out in public. Nowadays as long as patients follow certain precautions, we typically do this as an outpatient treatment. The precautions are basically patients have to remain at home for about five days afterwards, depending on the dose of radioactive iodine they’re getting. They have to agree to have separate sleeping arrangements, separate bathroom facilities, that way patients are obviously more comfortable at home and as long as they follow these precautions there is minimal risk to anybody else around from radiation.
It’s kind of a paradox isn’t it that you’re making a person radioactive in order to kill the cancer?
Dr. Shivnani: Exactly, yes. It’s what we do in our specialty every day is using radiation to treat cancer. It’s important that we do it in a way that involves the lowest amount of radiation possible with a minimal amount of risk to other people, in a way that’s most targeted to the area that we need to treat. For thyroid cancer this has been the best treatment that we’ve had over the last fifty years.
I guess it’s the same as with radiation, it’s harmful to the body right?
Dr. Shivnani: Right. Too much is harmful to the body so when we use it we have to use it again in the right dose at the right area of the body for the right purpose. Anytime we’re recommending radiation, we’re looking at what are the risks of giving radiation, what are the benefits and does it justify giving radiation in this particular case.
Typically we think of radiation like an X-ray or somebody shooting some kind of beam at you. Or is that a misconception?
Dr. Shivnani: No that’s accurate. A lot of the patients that I treat with radiation are getting what’s called external beam radiation. They come to our cancer center and they’re lying on a table, a machine is pointing radiation at some part of the body. This treatment is a radio isotope and it’s a radioactive pill because we find that, that does a better job of being selective at going to the thyroid cells without exposing the other parts of the body to too much radiation.
That’s why it’s better?
Dr. Shivnani: Correct. For thyroid cancer and the most common type of thyroid cancer that we see this is the best treatment.
When was all this approved?
Dr. Shivnani: This treatment has been around for several decades. It has a long track record of being safe and effective. That’s why we typically use it and nothing has been shown to be better after surgery than the radioactive iodine. There are times where these thyroid cancers develop resistance to radioactive iodine and then that’s where some of the newer treatments that have been developed for thyroid cancer is becoming more widely used.
I imagine you have access to all of them in your toolbox?
Dr. Shivnani: Yeah, some of them are still undergoing clinical study, but a lot of them are available at our cancer center now.
In terms of what is the latest and newest thing about thyroid cancer, it’s showing up in younger people?
Dr. Shivnani: And at a high incidence. We’re seeing more patients at a younger age develop thyroid cancer. And it’s more than just what we would expect because of increased use of medical imaging and finding incidental thyroid cancers. We don’t fully understand why that is.
You mentioned that a child who is exposed to maybe too much radiation or something could develop… Again that seems pyridoxal, radiation is causing the cancer and radiation is treating the cancer.
Dr. Shivnani: Right. We don’t think that radiation is causing all of the cases of thyroid cancer; it’s just a possible risk factor. Whenever anybody comes to us with a diagnosis of thyroid cancer we ask if they were exposed to radiation as a child. Some of those cases are related to radiation but nowadays most you know, people that grew up in the seventies or eighties would not have been exposed to radiation for those purposes that were being used in the forties and fifties.
Because we know a lot more now?
Dr. Shivnani: Correct. And we don’t use radiation on kids unnecessarily. A lot of times, there were different forms of acne treated with radiation, and different types of fungal infections were treated with radiation. They worked for those purposes, but we don’t do that anymore because we know that down the road there’s more harm and there are other ways to treat those conditions without using radiation.
There’s a lot of sea salt now, there’s a lot of different types of salt that do not have iodine. Do you recommend against using those, just as a dietary thing?
Dr. Shivnani: Not necessarily, but when we’re preparing patients for treatment, because this is a radioactive form of iodine, we need the rest of their body to have a low amount of iodine so that this treatment is effective. Before we do this treatment, we start patients on what’s called a low iodine diet for two weeks before the treatment. And so we encourage patients not to have any outside food because that outside food, if it’s fast food or what have you, has salt in it and that salt is iodized salt. We tell patients to try to avoid that for the two weeks before this treatment, and it’s an inconvenience, but the whole point of it is to try to make sure that this treatment is as effective as possible. This way hopefully they never have to go through it again.
Is there any thought in the research that somehow this increase in thyroid cancers could be caused by just other things in our diet?
Dr. Shivnani: It’s possible. I mean a lot of things are being looked at and thought about but nothing has been proven yet as far as diet.
I know about the huge trend of hormone replacement therapy, some people are looking at the thyroid and measuring the hormone levels, coming up with all kinds of recommendations based on that. What’s the sense of that, what are they finding and are they on target with that?
Dr. Shivnani: I think there are some patients that are requesting to receive thyroid supplementation because they’ve gained weight and they think that it’s because of their thyroid, when really there is another explanation for it. Sometimes patients are being unnecessarily or inappropriately treated with thyroid hormone when their thyroid really isn’t low to begin with. It’s important that, like a lot of organs in our body, it shouldn’t be over functioning, it shouldn’t be under functioning and we shouldn’t try to mess too much with it as long as we feel like it’s functioning normally. Our bodies were meant to function in a certain way, and the vast majority of the time they do and so a lot of times we have other reasons for trying to treat certain things that may or may not need to be treated. It’s important to talk to your doctor about it before you start taking a supplement or something like that where we’re not really sure if it’s necessary.
In Mitzi’s case how would you assess how well she’s done from where she was to where she is?
Dr. Shivnani: She’s done great. Her treatment went perfectly and now she’s following closely with the endocrinologist periodically. They’re doing blood work, they’re doing scans to make sure there’s no sign of recurrence. Typically we do that with ultrasound so she’ll be followed closely for the next several years with the endocrinologist.
So you don’t necessarily see her that much anymore?
Dr. Shivnani: Correct.
Your job is in a sense done if the cancer is gone and you’re not treating the cancer?
Dr. Shivnani: Right. We don’t typically follow patients as long as they’re seeing the endocrinologist because they’re kind of the main quarterback for patients with thyroid cancer. But if there is an unfortunate case where the thyroid cancer comes back and we need to do the radioactive iodine treatment again, then the endocrinologist will send the patient back to us.
END OF INTERVIEW
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Anand Shivnani
972-542-8609
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