Anaplastic Thyroid Cancer Overview

A rare, aggressive form of the disease

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Anaplastic thyroid cancer (ATC) is a fast-growing and aggressive type of thyroid cancer. Also known as undifferentiated thyroid cancer, the disease involves the rapid division of cancer cells that don't or barely resemble or act like normal thyroid cells.

Anaplastic cancers can grow as quickly as several weeks and 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.

Symptoms of Anaplastic Thyroid Cancer

The first signs of anaplastic thyroid cancer are typically related to the enlargement of the thyroid gland—a bow-tie-shaped endocrine gland located in the neck, below the Adam's apple area.

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

What Causes Anaplastic Thyroid Cancer?

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. They include BRAF, RAS and TP53, but also EIF1AX, CTNNB1, PIKC3A, PTEN, and AKT1. These mutations and their relationship to ATC remain under study.

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 an injection of local pain medication. After the procedure, you will need stitches for your wound.

A biopsy sample of anaplastic thyroid cancer 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.

Molecular studies of the genetic mutations are critical to a diagnosis of ATC and guide treatment options, including tyrosine kinase inhibitors and immunotherapy agents.

Thyroid Cancer Doctor Discussion Guide

Get our printable guide for your next doctor's appointment to help you ask the right questions.

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Stages of Anaplastic Thyroid Cancer

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 anaplastic thyroid cancer 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 metastasizes into the trachea, lymph nodes, lungs, and bones. In as many as 25% of cases, infiltration of the trachea is already present at the initial diagnosis of the condition.

The spread of ATC to the bones, lungs or brain is estimated to have already occurred in as many as 50% of cases by the time of ATC diagnosis.

Anaplastic Thyroid Cancer Treatment

Unfortunately, the prognosis for ATC is very poor, with only half of people surviving six months after diagnosis. However, treatment can prolong survival. Less often the entire cancer can be removed by surgery following an early diagnosis, but in these cases, people can live for years.

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

There are several treatment approaches:

  • Surgery: Anaplastic thyroid cancer 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 anaplastic thyroid cancer tumor within the thyroid gland are not typically responsive to chemotherapy.

Gene Therapy and ATC

Some 50% to 60% of ATC cases demonstrate mutations in BRAF and RAS genes, which are important to the diagnosis. There are new ATC treatment approaches under study, but it's a challenge due to more aggressive genetic activity with ATC when compared with other thyroid cancers. Targeted treatments include tyrosine kinase inhibitors (TKIs).

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.

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What Patients Should Know About Thyroidectomy

A Word From Verywell

A diagnosis of an aggressive form of cancer, like anaplastic thyroid 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 healthcare provider about your options and any concerns.

9 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. National Cancer Institute. Anaplastic.

  2. National Cancer Institute. Anaplastic thyroid cancer.

  3. U.S. National Library of Medicine. MedlinePlus. Anaplastic Thyroid Cancer.

  4. Columbia University Irving Medical Center. Columbia Thyroid Center. Anaplastic Thyroid Cancer.

  5. Araque KA, Gubbi S, Klubo-Gwiezdzinska J. Updates on the Management of Thyroid Cancer. Horm Metab Res. 2020 Aug;52(8):562-577. doi:10.1055/a-1089-7870.

  6. American Thyroid Association. Thyroid Cancer.

  7. Columbia University Irving Medical Center. Anaplastic Thyroid Cancer.

  8. Nylén C, Mechera R, Maréchal-Ross I, Tsang V, Chou A, Gill AJ, et al. Molecular Markers Guiding Thyroid Cancer Management. Cancers (Basel). 2020 Aug 4;12(8):2164. doi:10.3390/cancers12082164.

  9. Smith N, Nucera C. Personalized therapy in patients with anaplastic thyroid cancer: targeting genetic and epigenetic alterations. J Clin Endocrinol Metab. 2015;100(1):35-42. doi:10.1210/jc.2014-2803

Additional Reading

By Mary Shomon
Mary Shomon is a writer and hormonal health and thyroid advocate. She is the author of "The Thyroid Diet Revolution."