Thyroid biopsy: Purpose, process and recovery

The thyroid is a butterfly-shaped gland in the front of your lower neck. A thyroid biopsy is a procedure that helps diagnose or rule out thyroid cancer.

As an oncologic endocrinologist at MD Anderson, I often perform thyroid biopsies and order thyroid biopsies to be performed by radiologists. Here, I’ll answer some of the most common questions I get about them.

Why would my doctor order a thyroid biopsy?

A doctor usually orders a thyroid biopsy to evaluate a thyroid nodule further. A thyroid nodule is a lump that grows within the thyroid gland.

When you have a thyroid biopsy, the doctor uses a small needle to remove a tissue sample from the thyroid nodule. The sample will then be examined to see if it’s cancerous.

Can you see thyroid nodules?

It depends on the size of the nodule and where it’s located in the thyroid gland.

A nodule on the front of the thyroid can pop out enough to be seen. But if the nodule is in the middle or the back of the thyroid, you won’t be able to see it unless it grows large enough to push your whole thyroid out. In this case, it may look like an enlarged thyroid.

Typically, you can’t see a nodule that is less than 1 to 2 centimeters in size. Thyroid nodules are often easier to see in people with a thin neck because there is less tissue covering the thyroid. People who have lost a lot of weight might notice a thyroid nodule for the first time.

Sometimes, doctors can feel a thyroid nodule during a physical exam. It’s pretty common for thyroid nodules to be found incidentally when people have medical imaging done for an unrelated reason.

What can a thyroid biopsy tell you?

A thyroid biopsy can help diagnose thyroid cancer. It can also tell us if there is metastasis from cancer that started in another part of the body and spread to the thyroid.

Thyroid nodules are very common. Most of the time, they are not cancer. A thyroid biopsy could show other thyroid conditions, such as:

Hashimoto’s disease

This is an autoimmune disease in which the immune system attacks the thyroid, resulting in an underactive thyroid.

Graves’ disease

This is an autoimmune disease that causes an overactive thyroid, which means the thyroid makes too much hormone.

Thyroiditis

This is inflammation of the thyroid, which can cause an underactive or overactive thyroid.

What percentage of thyroid biopsies are cancerous?

MD Anderson pathologists will classify a thyroid sample in one of four broad categories:

• Benign: Noncancerous
• Malignant: Cancerous
• Insufficient: There was not enough of the sample to make a diagnosis.
• Indeterminate: We cannot tell whether it’s cancer because it may have some uncommon features or abnormal cells, but not enough to make a cancer diagnosis.

At MD Anderson, 60% to 70% of our thyroid biopsies come back benign; 5% come back as cancerous. The other 25% to 35% are indeterminate.

We offer Rapid On-site Evaluation (ROSE), a practice that helps our pathologists ensure there is enough tissue to make a diagnosis. Using this method, pathologists analyze the sample immediately. If there is not enough sample to make a diagnosis, your doctor may obtain more sample tissue to make the diagnosis.

If biopsy results are indeterminate, your doctor may order molecular testing for gene mutations or fusions. This helps predict which nodules are cancerous versus noncancerous. Molecular testing has been found to reduce the number of unnecessary surgeries. If you have an indeterminate biopsy that is unlikely to be cancer, your doctor will continue to monitor the nodule.

What can I expect during a thyroid biopsy?

There’s nothing specific you need to do to prepare for a thyroid biopsy. Tell your doctor if you are taking any blood thinners; they may want you to stop taking them before the biopsy. This is because blood thinners may increase the chance of bleeding during the biopsy, which can affect your results and increase the chance of bruising at the biopsy site.

The procedure

On the day of your appointment, you will go to the hospital or clinic and be asked to change into a gown. Then, you will lie down on your back, and the doctor will cleanse the skin over the thyroid gland with an antiseptic. The doctor will then put gel on your neck and use the ultrasound to find and measure the thyroid nodule. After that, the doctor will give a local anesthetic to numb the area.

Once the area is numb, your doctor will carefully put a small needle through your skin and into the thyroid nodule, using the ultrasound to guide them. The doctor will then use a syringe to take a small sample of cells from the nodule. This is called an ultrasound-guided thyroid biopsy. Most people do not feel pain during the procedure. After the needle is removed, your doctor will press on your neck and cover the area with a bandage or gauze. After that, you are free to go home.

Recovery after the procedure

We recommend leaving the bandage on for four hours. You should not shower or allow the area to get wet for 24 hours after the biopsy.

You can resume your normal activities the same day. If you have any pain once the anesthesia wears off, we recommend taking acetaminophen or applying an ice pack to the area for 20 minutes at a time.

Getting your results

A pathologist will analyze the sample, which can take a few days up to 2 weeks. Once the results are ready, the pathologist will share the results with your doctor. Your doctor will then go over the results with you. If the results show that the nodule is benign, your doctor will monitor it regularly to check for any changes. Your doctor may recommend another biopsy if the nodule grows, or if anything concerning is found. 

If the biopsy shows cancer, your doctor will discuss a treatment plan with you. When thyroid cancer is caught early, it is often successfully treated with surgery. In some cases, the plan may also include thyroid hormone therapy and radioactive iodine treatment. For more advanced thyroid cancer, your doctor may suggest targeted therapy, immunotherapy or external beam radiation therapy.

Steven Weitzman, M.D., is an oncologic endocrinologist who specializes in ultrasound-guided thyroid biopsies.

Request an appointment at MD Anderson online or call 1-877-695-0709.