Thyroid Disease

Different Types of Thyroid Cancer

An Overview of Thyroid Cancer

Thyroid cancer refers to cancer that occurs in your thyroid gland. Your thyroid is a small, butterfly-shaped gland located in your neck. It produces hormones that regulate how your cells, organs, tissues, and glands use oxygen and energy.

According to the American Cancer Society, it's estimated that in 2016 about 62,450 new cases of thyroid cancer will be diagnosed (49,350 in women, and 19,950 in men).

Thyroid cancer is the most rapidly increasing cancer in the U.S., with the number of diagnoses tripling over the past 30 years. There is disagreement as to whether this is due to more detection of smaller thyroid cancers due to use of ultrasound technology, or an actual increase in the incidence of thyroid cancer.

Thyroid cancer is, however, considered one of the least deadly and most survivable cancers, and five-year survival rates for thyroid cancer are almost 97 percent.

According to the American Cancer Society, in 2016, about 1,980 people will die from thyroid cancer (1,070 women and 910 men). 

Types of Thyroid Cancer 

There are four different types of thyroid cancer:

Papillary thyroid cancer makes up about 80 percent of all thyroid cancer cases. Papillary cancer mostly involves one side of the thyroid and sometimes spreads into the lymph nodes. The cure rate is very high. 

Follicular thyroid cancer makes up about 15 percent of all thyroid cancer cases. It tends to be more aggressive than papillary cancer. The thyroid gland is comprised of follicles which produce thyroid hormones.

While the spread of follicular thyroid cancer is not common when it does, cancer doesn't usually spread to the lymph nodes, but instead can spread to arteries and veins of the thyroid gland and more distantly, to the lungs, bones, or skin. The long-term survival rate is high.

Medullary thyroid cancer makes up about 3 percent of all thyroid cancer cases. This type of thyroid cancer originates in the upper central lobe of the thyroid. It spreads to the lymph nodes much earlier than papillary or follicular cancers. Medullary thyroid cancer differs from papillary and follicular cancer in that it does not arise from cells that produce thyroid hormone, but instead from C cells. These C cells make the hormone calcitonin. This type of cancer can run in families and also has a good cure rate.

Anaplastic thyroid cancer is the rarest thyroid cancer, making up about 2 percent of all cases. It is also the most serious thyroid cancer. Anaplastic thyroid cancer can spread early to lymph nodes, and the initial diagnosis is often made based on a mass in the neck.

It also is the form of thyroid cancer most likely to spread to other organs beyond the thyroid or lymph nodes. This type of thyroid cancer is more common in those over 65 and in men. Long-term survival rates are far less than for the other three types of cancer.

Risk Factors 

  • Age: Thyroid cancer is more common in younger people, when compared to other adult cancers. Nearly two-thirds of those diagnosed with thyroid cancer are between the ages of 20 and 55. About 2 percent of thyroid cancers occur in children and teenagers.
  • Gender: Women make up almost 75 percent of all thyroid cancer cases.
  • Family History and Genetics: A family history of thyroid cancer increases your risk. There is also an abnormal gene called the RET oncogene that can run in families. The presence of this gene greatly increases your risk of developing the medullary form of thyroid cancer.
  • Personal Thyroid History: A personal history of Hashimoto’s and/or goiter
  • Radiation Treatments: for bone marrow, head and neck cancers, childhood cancers, and pre-1960 radiation treatments for acne, tonsils, and adenoids
  • Radiation Exposure: due to nuclear accidents, releases from atomic facilities, or weapons testing
  • Iodine Deficiency
  • Other inherited conditions: There are several inherited conditions that increase your risk of developing thyroid cancer, including familial adenomatous polyposis (FAP), Gardner syndrome, Cowden disease, Carney complex, type I

Signs and Symptoms 

Some people with thyroid cancer do not develop any symptoms. Most commonly, however, you may notice a lump at the base of the front of your neck.

Other symptoms may include: 

  • pain in your neck
  • enlarged lymph nodes 
  • swelling in your neck
  • a hoarse voice

Some symptoms of the rarest type of thyroid cancer—anaplastic thyroid cancer—include a rapidly growing lump in the neck, difficulty swallowing, coughing, and coughing up blood.

Diagnosis

Detection of Lump or Nodule

The process of diagnosing thyroid cancer usually starts with detection of a lump or nodule in your thyroid gland. In some cases, you may feel it yourself or even see it. Your doctor—or even a partner, hairdresser, or massage therapist—may detect it when handling your neck.

It's also fairly common for thyroid nodules to be discovered when you have x-rays of your head or neck. Even though most nodules or lumps in the thyroid are benign, you should always have it evaluated by a physician.

Physical Exam

During an exam, your doctor should feel your thyroid and the lump, assess the size of your thyroid, its firmness, and any asymmetry. The doctor will also look for any enlarged lymph nodes in your neck and area around the gland.

Imaging Tests

Your doctor may perform imaging tests and scans to evaluate your nodules. These tests include:

  • Nuclear scan, also known as radioactive iodine uptake (RAI-U) scan. In this test, you are given a radioactive tracer dose, followed by the scan. A radioiodine uptake (RAI-U) test is often performed to determine if the nodule is more visible and “hot” (absorbing iodine, and therefore likely to be benign), “warm” (absorbing some iodine, and potentially suspicious), or “cold” (absorbing no iodine, and suspicious).
  • Magnetic resonance imaging (MRI) can help detect enlargement in your thyroid gland, as well as tumors and tumor size. MRI can also be helpful in detecting the spread of tumors. 
  • Thyroid ultrasound can tell whether a nodule is a fluid-filled cyst or a mass of solid tissue—fluid-filled cysts are more likely to be benign—but it cannot determine if a nodule or lump is malignant.

Fine Needle Aspiration (FNA) Biopsy of the Thyroid

The next step is to biopsy warm or cold nodules to rule out or diagnose thyroid cancer. Thyroid nodules are biopsied using a needle, in a procedure known as "fine needle aspiration biopsy"—abbreviated FNA. In some cases, the biopsy is "ultrasound-guided" so that the nodule can be more accurately sampled by the physician or pathologist performing the biopsy. 

In the past, as many as 30 percent of FNA biopsies were considered inconclusive, or indeterminate, meaning that cancer couldn’t be ruled out. Typically, the next step was surgery to remove the thyroid, so that the nodules could undergo full pathological evaluation. The majority of those nodules ended up being benign, but the patients were left with no thyroid gland and lifelong hypothyroidism. Since 2011, however, there is a specialized test available, called the Veracyte Afirma Thyroid Analysis, that eliminates almost all indeterminate or inconclusive thyroid nodule biopsy results, preventing unnecessary surgery.

Blood Tests

Blood tests can’t diagnose thyroid cancer or detect a cancerous thyroid nodule. Your doctor may order a thyroid stimulating hormone (TSH) test, however, to determine if your thyroid is overactive or underactive.

If your doctor suspects medullary thyroid cancer, calcium testing may be ordered. High levels can be indicative of medullary thyroid cancer. Genetic testing may also be recommended to identify whether you have the the abnormal RET gene associated with some cases of medullary thyroid cancer.

Laryngoscopy

If your thyroid nodule is close to your larynx (voice box), your doctor may order a laryngoscopy. This test involves inserting a lighted flexible tube to view your larynx at high magnification. 

Self-Exam - The Thyroid Neck Check

To emphasize the importance of early detection, the American Association of Clinical Endocrinologists (AACE) also recommends that everyone periodically perform a self-exam they call the “Thyroid Neck Check.” The purpose of this self-exam is to help you discover find lumps or enlargements in your neck that may point to thyroid conditions, including thyroid cancer. But it does not replace an exam by a physician, nor can it diagnose or rule out thyroid cancer.

Here are the steps in a thyroid neck check:

1. Stand in front of a mirror.
2. Stretch your neck back.
3. Swallow water.
4. Look for enlargement in your neck (below the Adam's Apple, above the collar bone).
5. Feel the area to confirm an enlargement or bump.
6. If you feel or see anything unusual, see a doctor.

Treatment 

Treatment for thyroid cancer depends on the type of cancer, the size, and staging, among other factors.

Surgery/Thyroidectomy

In most cases of thyroid cancer, the entire thyroid gland is surgically removed, known as a thyroidectomy. If there is concern that cancer has spread to your lymph nodes in your neck, another procedure to remove the lymph nodes—known as a neck dissection or lymphadenectomy—may also be performed. (Note: If you have a small papillary thyroid cancer, experts now agree that you may only need part of your thyroid removed, not the entire gland.)

Since thyroid surgery is not very common, it’s important that you find an experienced thyroid surgeon who has performed many thyroidectomies. You may want to learn more about what to expect from thyroid surgery, what your recuperation will be like and the potential complications you might face after thyroid surgery.

If your parathyroid gland is damaged during surgery, you also need to take vitamin D and calcium supplements after surgery to help maintain normal calcium levels.

Radioactive Iodine (RAI)

Depending on your type of thyroid cancer, the extent of cancer, and how aggressive it is, radioactive iodine (RAI) treatment, also known as remnant ablation, may be given after surgery. The purpose of RAI is to kill off any thyroid tissue remaining after the thyroid surgery, to that cancer can’t regrow in that tissue.

After thyroid surgery (and RAI if given), you will need to be on thyroid hormone replacement medications. Depending on the type of thyroid cancer and the risk of recurrence, your doctor may recommend that your dosage is high enough that it is "suppressive," meaning that the amount of medication you take keeps your TSH level low or undetectable, to help prevent a recurrence of cancer.

In preparation for a scan to evaluate the effectiveness of surgery/RAI, you may need to stop taking any thyroid hormone replacement long enough for TSH levels to rise—usually over several weeks. This is accompanied by a low-iodine diet. A scan is then performed to look for any remnant thyroid tissue. A second RAI may be recommended if remnant tissue is discovered.

External Beam Radiation

External-beam radiation therapy is sometimes recommended if an advanced thyroid cancer did not respond to the RAI.

Targeted Therapies

A variety of targeted therapies are now being used for thyroid cancer that is resistant to RAI, or in the case of certain types of metastasis. These include sorafenib (Nexavar), lenvatinib (Lenvima), vandetanib (Caprelsa), and cabozantinib (Cometriq).

Monitoring and Follow-up

The prognosis for most types of thyroid cancer is very good. The risk of recurrence, however, is as much as 30 percent and can occur decades after your initial diagnosis and treatment. So periodic monitoring is necessary to check for any possible recurrence of cancer. Depending on the type of thyroid cancer, monitoring may include:

  • Periodic testing of your thyroglobulin (Tg) levels, which tend to rise if any remaining thyroid tissue is become active or cancerous
  • A scan for recurrence, after you stop taking thyroid hormone medication and TSH rises, while you follow a low-iodine diet. A drug called Thyrogen is available during this time to help relieve hypothyroidism symptoms, while still allowing an accurate scan.
  • Imaging tests, such as ultrasound, PET scan, MRI or CT scans 

Special Considerations: Anaplastic Thyroid Cancer

Typically, anaplastic cancer is treated with surgery to remove the tumor, followed by radiation to the tumor. Often, however, anaplastic thyroid tumors have become attached to vital structures within the neck, or have infiltrated the trachea, making them inoperable.

When an anaplastic tumor has infiltrated the windpipe, surgery may be needed to insert a tube in the throat to ease breathing—tracheotomy. In some cases, chemotherapy is used to treat metastatic disease, however, anaplastic tumors themselves are typically not responsive to chemotherapy.

Special Considerations: Thyroid Cancer in Pregnancy

If you are pregnant, the approaches to diagnosis and treatment are somewhat different. If a nodule is detected, your doctor will likely start with a thyroid blood test. If you have a family history of medullary thyroid carcinoma, calcitonin levels, and genetic testing may also be conducted. Radioactive iodine uptake testing is not performed during pregnancy.

If you have a small (less than 10 mm in size) nodule that is otherwise not suspicious, you doctor may recommend waiting until after pregnancy for further followup. If you have a nodule that is growing, or if you are having a persistent cough or vocal problems, or any other suspicious indicators, a fine needle aspiration biopsy is recommended and is considered safe during pregnancy.

If your nodule is benign, your doctor will recommend monitoring. If the nodules are compressing your trachea or esophagus, thyroid surgery will likely be recommended.

If thyroid cancer is found, the type of thyroid cancer determines the treatment. In some cases, surgery may be recommended, but deferred until after delivery, with an ultrasound performed each trimester to monitor your nodule(s). For aggressive cancers, or medullary cancer, surgery may be recommended.

In some cases, thyroid hormone replacement treatment may also be recommended to help suppress your TSH levels and slow the spread of any cancer. 

An important note: When thyroid surgery is necessary for a pregnant woman, it is usually performed only during the second trimester, considered the safest time for both mother and fetus.

A Healthy Life After Thyroid Cancer 

After thyroid cancer treatment, you will be functionally hypothyroid, so it’s important to know about thyroid hormone replacement treatment, and other ways to resolve any hypothyroidism symptoms you may experience.

A good resource is this detailed article on understanding hypothyroidism.

Also, be aware that as a thyroid cancer patient, you face a significantly increased risk of developing a second primary cancer and that risk is highest in the first year after thyroid cancer diagnosis. So, regular checkups with your physician are important following thyroid cancer treatment.

Support and Information 

If you've just been diagnosed with thyroid cancer, read this letter to all newly diagnosed thyroid cancer patients to get up to speed on key things you need to know.  

If your friends, family, and coworkers don't understand what it's like to have a thyroid problem and face thyroid cancer, give them a copy of this important letter to help them get a sense of what you're going through: "When Your Family Member or Friend Has Thyroid Disease: An Open Letter to the Family and Friends of Thyroid Patients." 

One important thing to realize is that because thyroid cancer is not common, doctors—even some endocrinologists—have very little experience with diagnosis and treatment. It’s important to find and work with a knowledgeable expert who has ongoing experience working with many thyroid cancer patients. The Thyroid Cancer Survivors’ Association can help you find a thyroid cancer expert. Each year, the Thyroid Cancer Survivors' Association (ThyCa) also coordinates an international patient conference. You, your family, and caregivers can learn more about living well with thyroid cancer in many informational sessions. Many patients find this conference very helpful. ThyCa also has online and in-person support groups. 

It’s also important to learn as much as you can. You can read about thyroid cancer here that you know the type of thyroid cancer you have, the stage, whether it has spread, the pros and cons of recommended treatments. If you need to, write down your questions before a visit, and bring a friend or family member along to visits to help act as a support and surrogate for you.

It’s also important to learn as much as you can. You can read about thyroid cancer here at Verywell. We also recommend two free PDF guides available for download, called Thyroid Cancer Basics from the Thyroid Cancer Survivor’s Association, and What You Need to Know About Thyroid Cancer from the National Cancer Institute. Also, be sure to ask your doctors questions, to be sure that you understand your diagnosis and treatment. Make sure that you know the type of thyroid cancer you have, the stage, whether it has spread, the pros and cons of recommended treatments. If you need to, write down your questions before a visit, and bring a friend or family member along to visits to help act as a support and surrogate for you.

A Word From Verywell 

One of the biggest challenges to many thyroid cancer patients is the tendency of doctors, the media, and even friends and family to say, "You’re lucky. Thyroid cancer is the 'good cancer.'" Very few people consider any cancer a "good cancer" and many patients find this infuriating and invalidating. The truth is that most forms of thyroid cancer are very treatable and survivable, hence the “good cancer” label. But you may find it helpful to read more about this “good cancer” issue and why many thyroid cancer patients find it frustrating.

Sources:

American Cancer Society. “Thyroid Cancer.” http://www.cancer.org/cancer/thyroidcancer/index 

Braverman L, Cooper D. Werner & Ingbar's The Thyroid, 10th Edition. WLL/Wolters Kluwer; 2012.

Haugen A, Alexander K, Bible K, et. al. 2015 American Thyroid Association Management Guidelines for Adult Patients with Thyroid Nodules and Differentiated Thyroid Cancer. Thyroid. 2016; 26(1): 1-133. doi:10.1089/thy.2015.0020.

Smallridge R, Ain K, Asa S, et al. ​American Thyroid Association Guidelines for Management of Patients with Anaplastic Thyroid Cancer. Thyroid. 2012; Volume 22. doi: 10.1089/thy.2012.0302

Stagnaro-Green A, Abalovich M, Alexander E. et al. ​Guidelines of the American Thyroid Association for the Diagnosis and Management of Thyroid Disease During Pregnancy and PostpartumThyroid. 2011; Volume 21, Number 10, 2011 doi: 10.1089/thy.2011.0087

Thyroid Cancer Survivors' Association. "Thyroid Cancer Basics." 2012. http://www.thyca.org/download/document/350/TCBasics.pdf

Wells S, Asa S, Dralle H, et al. ​Revised American Thyroid Association Guidelines for the Management of Medullary Thyroid Carcinoma. Thyroid. 2015; Volume 25, doi: 10.1089/thy.2014.0335

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