Thyroid cancer is on the rise

MD Anderson Cancer Center
Date: 06-16-2014



Lisa Garvin:  Welcome to Cancer Newsline, a podcast series from the University of Texas MD Anderson Cancer Center. Cancer Newsline helps you stay current with the news on cancer research, diagnosis, treatment, and prevention providing the latest information on reducing your family's cancer risk. I'm your host, Lisa Garvin, and today our guest is Dr. Naifa Busaidy. She is an associate professor of endocrinoplasia and hormonal disorders here at MD Anderson. And our subject today is thyroid cancer. Thyroid cancer seems to be on the rise, at least in America. Is there a reason for that?

Dr. Naifa Busaidy: So yeah interesting question. There was quite a bit of controversy because there have been several studies that have come out that suggested that thyroid cancer is on the rise and several people had come out and thought that thyroid cancer was on the rise because we had better surveillance and better techniques to be able to image it. But actually a couple of studies have come out since to suggest that actually larger tumors are also on the rise. And we're not just simply picking up the smaller tumors that would be normally picked up by better surveillance techniques but we're also picking up the larger tumors and it's unclear why this may be occurring.

Lisa Garvin:  What is the ballpark number of Americans who get thyroid cancer each year?

Dr. Naifa Busaidy: The incidence of thyroid cancer has increased to about 50,000 people. The prevalence of thyroid cancer is about 400 to 500,000.

Lisa Garvin:  Now this is a cancer that typically strikes adults like about 20 to 55, correct?

Dr. Naifa Busaidy: Yes. It can actually strike younger. There's peak incidences on both ends of the spectrum, the older and the younger but the vast majority of them, yes would be in that age range.

Lisa Garvin:  As far as cancers are concerned, thyroid cancer is probably less serious than a lot of cancers. Is that correct?

Dr. Naifa Busaidy: Yes and no. So when -- I hesitate a little bit there because when people say that -- a lot of physicians will tell patients that if there's any cancer that you have to get thyroid cancer is the best one to get. Well first of all no one wants cancer. Second of all, while the vast majority of thyroid cancers, patients do survive and do well about 85 percent of patients will do well with the initial treatment which is surgery plus or minus radioactive iodine, there is still a number of patients that suffer quite a bit of morbidity and or mortality from the cancer. So since you don't know necessarily which category that's going to fit in, you don't want to tell the patient, well if there's any cancer you would like to have, thyroid cancer should be it. So that was the reason for my hesitation.

Lisa Garvin:  Okay. I had heard that the survival rate was actually approaching 97 percent but you're saying it's closer to 85.

Dr. Naifa Busaidy: Well the overall survival rate is 97 percent for papillary thyroid cancer which is the best of the four types of thyroid cancer. The number that I was quoting 85 percent; we were talking about patients having no evidence of disease after initial treatment.

Lisa Garvin:  Let's talk about the types of cancers. So there are four different types. Can you walk us through those?

Dr. Naifa Busaidy: Yeah. Papillary thyroid cancer is the most common type of thyroid cancer. Followed by follicular thyroid cancer, medullary thyroid cancer, and anaplastic thyroid cancer. When patients and or sites often talk about thyroid cancer, they're usually referring to papillary thyroid cancer because that makes up about 80 to 85 percent of thyroid cancers. And although they're all called thyroid cancer, three of the four of those types of thyroid cancers are derived from the original thyroid cell when we think about thyroid hormone producing cells. Medullary thyroid cancers actually made from a cell that happens to be within the thyroid but has nothing to do with the thyroid called C cells.

Lisa Garvin:  And that's one of the more serious types, the medullary thyroid?

Dr. Naifa Busaidy: Yes. Medullary thyroid cancer is different from the others in the sense that 20 percent of them can be familiarly genetic where most thyroid cancers are actually not. And the survival rate is shorter and has higher morbidity associated with it. It's harder to cure.

Lisa Garvin:  What is the genetic mutation that's behind medullary thyroid cancer?

Dr. Naifa Busaidy: So 20 percent of patients with medullary thyroid carcinoma will have a genetic mutation known as RET, r e t, which is a proto-oncogene that actually drives the cancer. And it can also have other associated endocrine tumors associated with the medullary thyroid cancer.

Lisa Garvin:  Now I would think that diagnosis is fairly straight forward. The thyroid is in the neck. It's pretty close to the skin. Do a lot of people catch it before they're diagnosed? Like they come in with a lump in their neck. How is diagnosis typically done?

Dr. Naifa Busaidy: So thyroid cancer diagnosis is actually very frequently, incidentally found. So patients will go into their local church health fair or have an ultrasound done for their neck vessels, the carotids and then they'll find oh there's a thyroid nodule there. And -- or a growth on the thyroid and so then they have to have further evaluation like ultrasounds dedicated to the thyroid itself and have a fine needle aspiration or a biopsy of that nodule to actually diagnose it.

Lisa Garvin:  Now we have a thyroid nodule clinic here at MD Anderson within the endocrine center. What is the role there? Is that like a diagnosis type clinic or how does that work?

Dr. Naifa Busaidy: Yeah. This was a clinic that was actually started in 2009 here at MD Anderson. We've always been seeing thyroid nodule patients. So the idea is to try to catch the thyroid cancer early. So if you can catch when it's a nodule located only in the thyroid prior to it having spread to the lymph nodes or to any other site, then you can have those patients directed into multidisciplinary specialty clinic that basically a one stop shop where the patient comes in, has a question. Do I have a thyroid nodule that needs something doing about? They see a practitioner. They have the ultrasound done and after they have their ultrasound with a biopsy, they come for the final evaluation and everything's wrapped up in that one day with a treatment plan in hand.

Lisa Garvin:  Are there benign nodules or benign cysts or things that occur on the thyroid?

Dr. Naifa Busaidy: Yes. So 85 to 90 percent of the growths noted on thyroids are noted to benign or noncancerous. And so they do not transform into cancer later. So the vast majority of patients that do have thyroid nodules do end up having nodules that are benign and noncancerous. But that has to be evaluated with ultrasound and a biopsy if necessary.

Lisa Garvin:  Now typically people who come here, what stage are they generally at? It sounds like you might be able to catch a lot of these early.

Dr. Naifa Busaidy: Yeah. So with good surveillance and ultrasound, thyroid cancers can be caught early although it's not something routinely we have a screening for. So, for example, like breast cancer or prostate cancer or colon cancer, we have screening programs for. With thyroid cancer, there isn't a good screening program. We don't recommend everybody going out and getting ultrasounds because about two-thirds of the population will have growths or nodules on their thyroid. But when it is found, it needs further workup. There currently is no program to surveil for these.

Lisa Garvin:  And what are the risk factors for thyroid? I'm hypothyroid and have been on medication for a long time for that. Is that a risk factor?

Dr. Naifa Busaidy: Usually not. The prevalence of hypothyroidism is large in the United States and in the world but the prevalence of thyroid nodules is also large with about two-thirds of people it being detected on some sort of imaging. So it's difficult to make a study to prove a cause and effect but there are several risk factors that can identify patients with thyroid nodules that are at risk for being malignant. And those are nodules that are larger. Nodules found in men. Patients with a history of external beam radiation exposure and particular for medullary thyroid cancer, a family history of thyroid cancer but there are some rare papillary thyroid cancers that do have familial associations with it as well.

Lisa Garvin:   Now typically when treating a thyroid, a thyroidectomy, it's not like -- of course it's a small organ or gland. I guess it's really a gland. With a thyroidectomy there's no sparing of the thyroid. You just take the whole thing out.

Dr. Naifa Busaidy: Okay. So if a patient has a benign thyroid nodule that needs to be removed or a nodule that's found that's what's called indeterminant meaning the biopsy could not tell whether it was malignant or not. Then in some instances half the thyroid or a hemithyroidectomy is recommended in which case just the other half of the thyroid is in place and there are several advantages to that. One is that the patients can -- 50 percent of the patients may not require thyroid hormone replacement or the tablets of thyroid hormone. And also the potential for complications from surgery are lower. If a patient has thyroid cancer especially if they have larger thyroid cancers, the total thyroidectomy is recommended which is the removal of the whole thyroid. There is some controversy that exists if the patients have smaller thyroid cancers whether half the thyroid or hemithyroidectomy can be done and is advocated in many places.

Lisa Garvin:   So have there been incidences of recurrence of people who have kept all or part of their thyroid who have had cancer?

Dr. Naifa Busaidy: Yes there have been studies looking at recurrence of thyroid cancer in general in patients who have had small sized tumors. And albeit many of them have not been done in a prospective fashion, most of the thyroid cancer research was in a retrospective fashion and recurrence rates seem to be low overall especially in tumors that are smaller than 2 sonometers or even a sonometer and a half.

Lisa Garvin:  What is the typical treatment? I mean obviously surgery is part of it but is there a role for chemotherapy and or radiation therapy?

Dr. Naifa Busaidy: Yeah. So the typical treatment for differentiated thyroid cancer which is the two most common, the papillary and follicular thyroid carcinoma, is to do a total thyroidectomy, removal of the whole thyroid, with or without lymph nodes removed. If any lymph nodes are involved with the cancer, imaging before surgery or by the surgeon during surgeon and the key there is finding a good surgeon who knows and does thyroid cancer because the surgery can be different itself and the identification of the involved lymph nodes can be a difficult process with low risk of complications. The second treatment after surgery is radioactive iodine. So the thyroid naturally uses iodine to make thyroid hormone and so if you make that iodine radioactive and the patient can ingest that iodine, the iodine will tend to hone into normal thyroid tissue or thyroid cancer and burn it off or get rid of it. So it's actually one of the original molecular targeted therapies because it actually targets the thyroid and thyroid cancer which is exciting and came out very early on. And then the third treatment after surgery and radioactive iodine is to give patients a thyroid hormone pill because they no longer have a thyroid to help control what the thyroid naturally controls. We give the patients a little more thyroid hormone than their body needs to keep the cancer from coming back which is a nice form of a simple anticancer therapy. About 85 percent of patients have no evidence of disease with those treatments alone which is surgery and radioactive iodine and the thyroid hormone. About 5 to 15 percent of patients with thyroid cancer does recur. And in those instances the current best treatments are further surgery plus or minus radioactive iodine if their tumors do continue to take up radioactive iodine. The role of external beam radiation which is different from the radiation that comes from radioactive iodine is small in differentiated thyroid cancer and in medullary thyroid cancer but it's a large part of the treatment for anaplastic thyroid cancer or the more rare thyroid cancer. So in the more common thyroid cancers with the differentiated thyroid cancer it is only used typically in patients where they've had good surgery with surgeons that do thyroid cancer and the surgeon says we should not try to go back into this neck. And there's good removal of all the disease that can be seen as opposed to disease being left behind. So it's a small role. We tend to not give it much in differentiated thyroid cancer. In anaplastic thyroid cancer which is a more rare cancer, it is front and center part of the treatment to be given for those patients. The role of systemic therapy or chemotherapy after radioactive iodine has a small role but it's an evolving role. The patients who have the advanced thyroid cancer that cannot be cured with surgery or radioactive iodine that is progressing or growing is where we tend to give these patients the targeted therapies or systemic therapies. This role has been evolving in the last five years or so and these therapies tend to target -- starving the tumors of its blood supply and target abnormal proteins that make the cancer grow. And there have been lots of research in this area that's been changing the face of thyroid cancer where we're trying to advanced to a more personalized cancer therapy for the thyroid cancers that are advanced which again is a small minority but for those patients, we really need cures for them. Currently there is no cure but we are trying to move towards targeted therapies for them to get their cancer.

Lisa Garvin:  Is there anything the general public can do? Obviously there's no standardized screening but is there anything people can do like have their doctors during their physical feel their glands under their jaw? I mean is there any way that they can get ahead of this absent a screening regimen?

Dr. Naifa Busaidy: Yeah. So I think the role of the primary care physician and gynecologist, very frequently a lot of our referrals will be from the gynecologist because most of the patients are women that develop thyroid cancer and a lot of them only have a gynecologist as their primary care physician. So a physical exam of the thyroid and the neck can be very useful in diagnosing thyroid cancers in lymph nodes although you can't tell by physical examination. It can lead you to the ultrasound. However a vast majority of the thyroid cancers are small and may not be felt on palpation on physical examination. So that can be difficult.

Lisa Garvin:  So Dr. Busaidy even though people want to say that thyroid is an easy cancer. It really is not as easy all that and really should require expert treatment, correct?

Dr. Naifa Busaidy: Absolutely. I think that diagnosing the cancer early is important and then getting the appropriate treatment from the beginning is important so that the patients dealing less with problems with multiple treatments and having to clean things up. So I think a patient with thyroid cancer or even with a thyroid nodule should seek expertise. Seek out physicians and multidisciplinary groups. So the endocrinologists, the surgeons, the oncologists, and the radiation docs that are necessary in one team that can work together to treat them right from the beginning.

Lisa Garvin:  Well great. Thank you very much for being with us today.

Dr. Naifa Busaidy: Thank you.

Lisa Garvin:  If you have questions about anything you've heard today on Cancer Newsline, contact Ask MD Anderson at 1-877-MDA-6789 or online at Thank you for listening to this episode of Cancer Newsline. Tune in for the next podcast in our series.