Head & Neck

Thyroid Cancer

The thyroid is a butterfly-shaped gland below the larynx (voice box) in the front of the neck. It produces hormones that help regulate the heart rate, body temperature, growth and metabolism.

Four parathyroid glands (not shown above) are pea-sized organs on the back of the thyroid. They produce hormones that control blood calcium levels. Thyroid tissues contain two types of cells. Follicular cells produce the thyroid hormone, and para-follicular cells (commonly called C-cells) produce a hormone involved in processing calcium.

There are four primary types. Papillary thyroid cancer is the most common, and it begins in the follicular cells, as does follicular thyroid cancer. Both are called differentiated cancers because their cells look similar to healthy thyroid cells when viewed under a microscope. They tend to spread and grow slowly. Medullary thyroid cancer begins in the C-cells. Medullary and anaplastic thyroid cancers are called undifferentiated or poorly differentiated, because their cells look very different from healthy thyroid cells. Both types grow and spread more quickly, and anaplastic is a very aggressive form.

It is common for people with thyroid cancer to have few symptoms, if any. The cancer is sometimes discovered on imaging scans or other tests performed to diagnose another medical condition. When symptoms do occur, they may include a lump, swelling or pain in the front of the neck; persistent hoarseness or voice changes; swollen neck glands; throat or neck pain; difficulty swallowing; trouble breathing; or a persistent cough without a cold.

Common Treatments

Talk with your health care team about the goal of treatment. Depending on your diagnosis, it may be to cure the cancer or to control it while relieving symptoms. As you discuss treatment options, be sure to learn the benefits and risks as well as any side effects or long-term effects of each type. This information will make you more prepared to make treatment decisions.

One or more of the following therapies may be part of your treatment plan. (See Treatment Options for general descriptions of each treatment type.)

Surgery

Surgery to remove all or most of the thyroid is the most common treatment for thyroid cancer, and various procedures and techniques may be available.

Lobectomy, also called hemithyroidectomy, may be used in some low-risk patients when only half of the thyroid needs to be removed.

Total thyroidectomy is used when the entire thyroid gland is removed. In this case, thyroid hormone can no longer be produced in the body. This means that medication must be taken as a replacement for the hormone. This treatment, which can be taken as a pill, is known as thyroid hormone therapy. Taking calcium and vitamin D supplements may also be necessary if the parathyroid gland function is affected by surgery.

In addition to removing the thyroid, your surgeon may also remove lymph nodes in the neck to see if the cancer has spread.

Radioactive Iodine Treatment

Because the thyroid absorbs almost all iodine that enters the body, radioactive iodine treatment can be used to treat remaining thyroid cells that were not removed by surgery or that have spread beyond the thyroid. This involves giving radioactive iodine (I-131) in liquid or pill form. The radioactive iodine will concentrate in any remaining thyroid tissue, and the radiation will kill the cancer cells. This treatment is standard of care for papillary or follicular thyroid cancer that has spread to lymph nodes in the neck or other parts of the body.

Radiation Therapy

This treatment is more often used as part of treatment for medullary and anaplastic thyroid cancer. It is usually given after surgery (adjuvant therapy) and concentrated on targeted cancer cells in a specific area. External-beam radiation therapy is usually given for about six weeks, once a day for 15 to 30 minutes, five days a week.

Immunotherapy

Immunotherapy in the form of immune checkpoint inhibitors may be an option for treating recurrent or metastatic thyroid cancer that has stopped responding to chemotherapy. Other immunotherapy options may be available in clinical trials.

Targeted Therapy

Certain targeted therapy drugs may be given to treat medullary thyroid cancer or to people with papillary or follicular thyroid cancer for whom standard treatment (surgery or radioactive iodine therapy) was not effective.

Targeted therapy in the form of tyrosine kinase inhibitors (TKIs) may also be an option if a neurotrophic tyrosine receptor kinase (NTRK) genetic fusion, a specific molecular (genetic) abnormality, is found in the tumor. This type of personalized treatment attacks the source of a tumor’s growth, focusing on certain parts of cells and the signals that cause them to grow unchecked or keep from dying. These signals are often sent by proteins called tyrosine kinases.

Other Treatment Options

Chemotherapy may be used if surgery and radiation therapy are not successful. Clinical trials may be another option. Ask your doctor if you are a candidate for a clinical trial, and research available trials on your own (see Clinical Trials).

Staging

Diagnosing your type of thyroid cancer is an important step in creating the best treatment plan for you. Your doctor will perform a thorough exam, imaging studies, blood tests and a biopsy and use these test results to stage the cancer. Staging determines the extent of your cancer, where it is located and whether it has metastasized (spread) to nearby organs, tissues or lymph nodes, or to other parts of your body.

The TNM staging system, developed by the American Joint Committee on Cancer (AJCC), is typically used to classify and stage thyroid cancer. This system classifies the cancer by tumor (T), node (N) and metastasis (M). The T category describes the size and location of the primary tumor. The N category indicates whether the lymph nodes show evidence of cancer cells. The number and location of these lymph nodes are important because they show how far the disease has spread. The M category describes metastasis (spread of cancer to another part of the body), if any.

Staging Criteria

Once the cancer is classified, an overall stage is assigned. Thyroid cancer may be Stage I through Stage IV. Stages I and II are generally confined to the local area where the cancer is found, and Stage III has spread to the regional lymph nodes in the neck. Stage IV is further divided into Stages IVA, IVB and IVC. Stages IVA and IVB are locally or regionally advanced disease, and Stage IVC has spread to distant sites, such as the liver, lungs or bone.

These basic stages are designed to group patients who have a similar prognosis (outlook). This grouping allows doctors to more accurately predict outcomes for patients depending on the type of treatment they receive. In certain cancers, the stage is also determined by other factors. For thyroid cancer, the subtype of cancer and age of the patient may influence the stage.

Sometimes your doctor may reassess your stage after treatment or if cancer recurs. This is known as restaging. It is rarely done but typically involves the same diagnostic tests used for the original staging. If a new stage is assigned, it’s often preceded by an “r” to denote that it’s been restaged and different from the original stage given at diagnosis.

Look carefully at the table headlines and sections to ensure you view the information that applies to your diagnosis as each has unique staging characteristics.

TNM Classification for Thyroid Cancer

Classification Definition
Tumor (T)
TX Primary tumor cannot be assessed.
T0 No evidence of primary tumor.
Anaplastic & Differentiated
T1 Tumor ≤ (not more than) 2 cm in greatest dimension limited to the thyroid.
  T1a Tumor ≤ (not more than) 1 cm in greatest dimension limited to the thyroid.
  T1b Tumor > (more than) 1 cm but ≤ (not more than) 2 cm in greatest dimension limited to the thyroid.
T2 Tumor > (more than) than 2 cm but ≤ (not more than) 4 cm in greatest dimension limited to the thyroid.
T3 Tumor > (more than) 4 cm limited to the thyroid, or gross extrathyroidal extension (extended beyond the thyroid) invading only strap muscles.
  T3a Tumor > (more than) 4 cm limited to the thyroid.
  T3b Gross extrathyroidal extension (extended beyond the thyroid) invading only strap muscles (sternohyoid, sternothyroid, thyrohyoid or omohyoid muscles) from a tumor of any size.
T4 Includes gross extrathyroidal extension (extended beyond the thyroid) beyond the strap muscles.
  T4a Gross extrathyroidal extension (extended beyond the thyroid) invading subcutaneous soft tissues, larynx, trachea, esophagus, or recurrent laryngeal nerve from a tumor of any size.
  T4b Gross extrathyroidal extension (extended beyond the thyroid) invading prevertebral fascia or encasing the carotid artery or mediastinal vessels from a tumor of any size.
Medullary
T1 Tumor is ≤ (not more than) 2 cm in greatest dimension limited to the thyroid.
  T1a Tumor is ≤ (not more than) 1 cm in greatest dimension limited to the thyroid.
  T1b Tumor is > (more than) 1 cm but ≤ (not more than) 2 cm in greatest dimension limited to the thyroid.
T2 Tumor is > (more than) 2 cm but ≤ (not more than) 4 cm in greatest dimension limited to the thyroid.
T3 Tumor is > (more than) 4 cm or with extrathyroidal extension (extended beyond the thyroid).
  T3a Tumor is > (more than) 4 cm in greatest dimension limited to the thyroid.
  T3b Tumor of any size with gross extrathyroidal extension (extended beyond the thyroid) invading only strap muscles (sternohyoid, sternothyroid, thyrohyoid or omohyoid muscles).
T4 Advanced disease.
  T4a Moderately advanced disease; tumor of any size with gross extrathyroidal extension (extended beyond the thyroid) into the nearby tissues of the neck, including subcutaneous soft tissue, larynx, trachea, esophagus or recurrent laryngeal nerve.
  T4b Very advanced disease; tumor of any size with extension toward the spine or into nearby large blood vessels, gross extrathyroidal extension (extended beyond the thyroid) invading the prevertebral fascia, or encasing the carotid artery or mediastinal vessels.
Node (N)
NX Regional lymph nodes cannot be assessed.
N0 No evidence of locoregional lymph node metastasis.
  N0a One or more cytologically (based on fine needle aspiration biopsy) or histologically (based on pathologic analysis of tissues after surgery) confirmed benign lymph nodes.
  N0b No radiologic or clinical evidence of locoregional lymph node metastasis.
N1 Metastasis to regional nodes.
  N1a Metastasis to level VI or VII (pretracheal, paratracheal, or prelaryngeal/Delphian, or upper mediastinal) lymph nodes. This can be unilateral (on one side) or bilateral (on both sides) disease.
  N1b Metastasis to unilateral (on one side), bilateral (on both sides), or contralateral (opposite side of thyroid tumor) lateral lymph nodes (levels I, II, III, IV or V) or retropharyngeal lymph nodes.
Metastasis (M)
M0 No distant metastasis.
M1 Distant metastasis.

Used with permission of the American Joint Committee on Cancer (AJCC), Chicago, Illinois. The original and primary source for this information is the AJCC Cancer Staging Manual, Eighth Edition (2017) published by Springer Science+Business Media.

Staging Anaplastic Thyroid Cancer

Stage T N M
IVA T1 - T3a N0/NX M0
IVB T1 - T3a
T3b, T4
N1
Any N
M0
M0
IVC Any T Any N M1

Staging Differentiated Thyroid Cancer*

Stage T N M
Younger than 55 years
I Any T Any N M0
II Any T Any N M1
55 years or older
I T1, T2 N0, NX M0
II T1, T2
T3a, T3b
N1
Any N
M0
M0
III T4a Any N M0
IVA T4b Any N M0
IVB Any T Any N M1

*Includes papillary, follicular, poorly
differentiated and Hurthle cell carcinoma

Staging Medullary Thyroid Cancer

Stage T N M
I T1 N0 M0
II T2, T3 N0 M0
III T1 - T3 N1a M0
IVA T4a
T1 - T3
Any N
N1b
M0
M0
IVB T4b Any N M0
IVC Any T Any N M1
 

 

Key Takeaways

  • The thyroid hormone helps regulate your heart rate, body temperature, growth and metabolism.
  • Of the four main types of thyroid cancer, papillary is the most common.

Additional Resources

 

Previous Next


Register Now! Sign Up For Our Free E-Newletter!

Read Inspiring Cancer Survivor Stories

Order Your Guides Here