What is anaplastic thyroid cancer?

Your thyroid is a butterfly-shaped gland in the lower front part of your neck. The hormones it makes are carried throughout your body to help regulate heat and energy.

Anaplastic thyroid cancer is one of four types of thyroid cancer. It’s very rare: The American Thyroid Association notes that this type represents less than 2 percent of all cases of thyroid cancer. It metastasizes, or spreads, quickly to other organs. It’s one of the most aggressive cancers in humans.

Anaplastic thyroid cancer is fast-growing. This means symptoms can progress in only a few weeks. Some of the first symptoms you might notice are:

  • a lump or nodule in the neck
  • difficulty swallowing food or pills
  • pressure and shortness of breath when you lie down on your back

As the cancer grows, you might also notice:

  • hoarseness
  • a visible, hard mass in the lower front part of your neck
  • enlarged lymph nodes
  • cough, with or without blood
  • difficult or loud breathing due to a restricted airway or trachea

Researchers aren’t sure about the exact cause of anaplastic thyroid cancer. It might be mutation of another, less aggressive form of thyroid cancer. It could also be the result of a series of genetic mutations, though no one’s sure why these mutations happen. However, it doesn’t seem to run in families.

Certain things may increase your risk of developing anaplastic thyroid cancer, including:

  • being 60 or older
  • having a goiter
  • previous radiation exposure to the chest or neck

During a physical examination, your doctor will feel your neck. If they feel a lump that could be a tumor, they’ll likely refer you to an endocrinologist or oncologist for further evaluation.

To determine whether the tumor is cancerous, you’ll need have a biopsy done. This involves taking a small tissue sample from the tumor using fine needle aspiration or core biopsy and examining it for signs of cancer.

If the tumor turns out to be cancerous, the next step is to figure out how advanced the cancer is. Anaplastic thyroid cancer grows very quickly, so it’s almost always diagnosed at a more advanced stage.

Imaging tests, such as a CT scan of your neck and chest, will give your doctor a better idea of how big the tumor is. These images will also show how far the cancer has spread.

In some cases, your doctor might also use a flexible laryngoscope. This is a long, flexible tube with a camera on the end that can help your doctor determine if the tumor is affecting your vocal chords.

Anaplastic thyroid cancer is stage 4 cancer. This stage is further divided as follows:

  • Stage 4A means the cancer is only in your thyroid.
  • Stage 4B means the cancer has spread into tissue around the thyroid and possibly the lymph nodes.
  • Stage 4C means the cancer has spread to distant sites, such as the lungs, bones, or brain and possibly the lymph nodes.

Anaplastic thyroid cancer requires immediate treatment since it spreads quickly. For about half of people who receive a diagnosis, the cancer has already spread to other organs. In these cases, treatments focus on slowing its progression and keeping you as comfortable as possible.

Unlike some other types of thyroid cancer, anaplastic thyroid cancer doesn’t respond to radioiodine therapy or thyroid-stimulating hormone suppression with thyroxine.

Your doctor will discuss with you all the available treatment options. They can help you choose one that’s best suited for both your condition and personal preferences.


Your doctor may refer to your cancer as being “resectable.” This meaning it can be surgically removed. If your cancer is unresectable, it means it has invaded nearby structures and can’t be completely removed with surgery. Anaplastic thyroid cancer is usually unresectable.

Other surgeries are palliative. This means they’re designed to improve your quality of life instead of treating the cancer.

For example, if you’re having trouble breathing, your doctor might suggest a tracheostomy. This involves inserting a tube into your skin, below the tumor. You’ll breathe through the tube and will be able to talk by placing your finger over the air hole. To avoid infection or blockage, the tube has to be removed and cleaned a few times every day.

If you’re having trouble eating and swallowing, you can have a feeding tube inserted through the skin into the wall of your stomach or intestine.

Radiation and chemotherapy

Chemotherapy alone isn’t very effective against this type cancer. However, it’s sometimes more effective when combined with radiation therapy. Radiation is directed at the tumor cells to shrink the tumor or slow its growth. It’s typically done five days a week for four to six weeks.

Radiation can also be used following surgery. This combination can help improve the overall outlook for people with stage 4A or 4B anaplastic thyroid cancer.

Clinical trials

By joining a clinical trial, you might gain access to investigational drugs or treatments that are otherwise unavailable. You’ll also be helping researchers learn more about anaplastic thyroid cancer in hopes of developing more effective treatments for it. You can search for relevant clinical trials in the United States here.

Find out more about clinical trials and what to expect in each phase.

With anaplastic thyroid cancer, time is of the essence. Once you have a diagnosis, you’ll need to work closely with your doctor to make crucial decisions and start treatment. If your doctor isn’t familiar with anaplastic thyroid cancer, ask for a referral to someone who is. Don’t feel uncomfortable about getting a second opinion from a different doctor as well.

Here are a few other things to discuss with your doctor as soon as possible:

  • treatment goals
  • clinical trials you may qualify for
  • medical advance directives and living wills
  • palliative and hospice care

You might also wish to speak with a legal expert about:

  • power of attorney
  • medical surrogacy
  • financial planning, wills, and trusts

Learning you have anaplastic thyroid cancer can be overwhelming. If you’re not sure where to turn or how to take the next step, consider these support sources:

If you’re caring for someone who has anaplastic thyroid, don’t underestimate your needs as a caregiver. Here are 10 things to help you take care of both you and your loved one.

Suggested reads

  • When Breath Becomes Air” is a Pulitzer Prize finalist written by a neurosurgeon who received a diagnosis of stage 4 lung cancer. It details his experience as both a doctor and a patient living with a terminal illness.
  • Dancing with Elephants” combines interviews with medical experts, mindfulness tips, and humor to help people with serious illnesses live joyfully and intentionally.
  • Life After the Diagnosis” is written by a doctor who specializes in palliative care. It provides practical information on everything from complex medical jargon to difficult treatment decisions for people living with terminal illnesses and their caregivers.
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Anaplastic thyroid cancer is very aggressive. Even with earlier detection, most people go on to develop metastatic disease. According to Columbia University, the five-year survival rate is under 5 percent.

However, because it’s so aggressive, anaplastic thyroid cancer is also the subject of a lot of innovative research. It may be worth it to seek out open clinical trials. Your doctor can help you look for one in your area.

Your doctor can also work with you to come up with a treatment plan to either slow the cancer’s progression or minimize your symptoms. Finally, don’t hesitate to tell your doctor if you feel like you need additional support. They’ll likely be able to guide you with local resources that can help.