An Overview of Anaplastic Thyroid Cancer

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Anaplastic thyroid cancer (ATC) is a rare, aggressive form of thyroid cancer. This type of cancer can cause severe compression of the structures in the neck, interfering with breathing, swallowing, and speaking. It can also metastasize (spread) rapidly throughout the body.

ATC typically begins after the age of 60 and, unlike other forms of thyroid cancer, it occurs most often in men. It is estimated that ATC makes up approximately 1 percent to 3 percent of all thyroid cancers in the United States each year.

Symptoms

The thyroid gland is a bow-tie-shaped endocrine gland located in the neck, below the Adam's apple area. It regulates the body's metabolism and energy levels.

The first signs of anaplastic thyroid cancer are typically related to compression of the structures in the neck, which results from physical enlargement of the thyroid gland.

While this type of cancer can cause symptoms of thyroid disease, such as weight loss or fatigue, these symptoms are not usually among the earliest signs of the condition.

The early signs and symptoms of anaplastic cancer include:

  • A mass in the neck that you can both see and feel
  • Rapid enlargement of the thyroid gland
  • A large lump on the thyroid gland
  • Swollen lymph nodes in the neck
  • Hoarseness or a change in the voice
  • Cough
  • Coughing up blood
  • Difficulty swallowing
  • Trouble breathing

Anaplastic thyroid cancer grows rapidly and can quickly infiltrate the trachea (windpipe), interfering with breathing. ATC is also one of the only types of thyroid cancer that can rapidly metastasize to other areas of the body.

Cause

The cause of anaplastic thyroid cancer is not known, but there are several risk factors that have been identified.

  • Previous thyroid cancer or enlargement: Most people diagnosed with anaplastic thyroid cancer also had another type of less aggressive thyroid cancer or an enlarged thyroid prior to developing ATC. It is not clear why these tumors increase the risk of developing ATC.
  • Radiation: A history of radiation exposure to the thyroid region is also among the risk factors associated with ATC.
  • Genetic mutations: There have been several genetic mutations identified in association with this disease. The genetic abnormalities identified in ATC are not believed to be hereditary and may develop at some point during life. There is no clear association between the genetic mutations found in ATC and disease prognosis, cause, or screening.

Diagnosis

If you have symptoms of neck compression due to thyroid enlargement, your diagnostic evaluation will include neck imaging studies, such as ultrasound, a computed tomography (CT) scan, or magnetic resonance imaging (MRI) of your neck and surrounding regions.

A diagnostic evaluation of a thyroid growth usually involves a biopsy as well. A biopsy is a sample of thyroid tissue, usually taken with a thin needle, that is then examined under a microscope. This is a minor surgical procedure that requires injection of local pain medication. After the procedure, you will need stitches for your wound.

A biopsy sample of ATC shows undifferentiated thyroid cells. They are not as well developed as regular thyroid tissue and appear less like well-functioning thyroid tissue than samples of other thyroid tumors.

Stages

As part of the diagnostic process, ATC is also staged. The disease is defined by how much it has invaded the body.

The stages of ATC are:

  • Stage IVA: The cancer is only found in the thyroid gland.
  • Stage IVB: The cancer has spread outside the thyroid gland to other areas of the neck.
  • Stage IVC: The cancer is metastatic and has spread to distant areas of the body through the bloodstream.

ATC typically metastasize into the trachea, lymph nodes, lungs, and bones. In as many as 25 percent of cases, infiltration of the trachea is already present at initial diagnosis of the condition. Spread of ATC to the lungs is estimated to have already occurred in as many as 50 percent of cases by the time of ATC diagnosis.

If you have had thyroid cancer or thyroid enlargement in the past, you may have had symptoms of thyroid disease or side effects of treatment prior to developing ATC.

Treatment

Unfortunately, the prognosis for ATC is very poor, and there is less than a 5 percent chance of survival at five years. However, treatment can prolong survival, and, in rare instances, the condition can be cured.

Treatment of ATC is focused on relieving the compression caused by the tumor, supportive control of symptoms, and radiation and chemotherapeutic treatment to control the growth of the cancer in the neck and elsewhere in the body.

There are several treatment approaches:

  • Surgery: ATC is often treated with surgery to remove the tumor from the thyroid gland and, if applicable, any surrounding structures the tumor has invaded. Sometimes ATC becomes attached to vital structures within the neck and may unfortunately be inoperable.
  • Supportive care for symptoms: If ATC infiltrates your windpipe, a tracheostomy (a surgical procedure done to insert a tube that then serves as an airway) may be necessary to ease breathing.
  • Radiation and chemotherapy: Radiation is often needed to shrink the tumor in the neck and elsewhere in the body. Chemotherapy is used to treat metastatic disease. However, remains of the ATC tumor within the thyroid gland are not typically responsive to chemotherapy.
  • Gene therapy: There are new treatment approaches that are currently being investigated for ATC treatment. They use targeted chemotherapy that is personalized for treatment of the specific molecular defects caused by the genetic mutations associated with ATC. This approach is currently considered investigational.

    Because there are not many available or effective treatments for ATC, you may also decide to participate in a clinical trial, potentially gaining access to new treatments that could be more beneficial than those currently available.

    A Word From Verywell

    A diagnosis of an aggressive form of cancer is among the most difficult challenges that a person or a family can face. Deciding which treatment approach to take depends on whether you can tolerate the recovery process after surgery and whether you are prepared to devote your time and energy to treatment with radiation and chemotherapy. Speak with your doctor about your options and any concerns.

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