How Do I Know If I Have Thyroid Cancer?


Medically Reviewed by Jennifer Robinson, MD on November 16, 2022

Thyroid nodules, or lumps, are very common. Most aren’t cancer.

Your thyroid is the small, butterfly-shaped gland usually located at the bottom front of your neck. If you have a lump on it, chances are you found it yourself, though your doctor may have detected it during a physical exam. If you have discovered a lump on your own, you should get your doctor to check it.

Physical Exam

Your doctor will examine any lumps, or nodules, you have on your neck. They might ask you some questions to find out if you’re at risk. The questions might be about whether you’ve been exposed to too much radiation, or if you have a family history of thyroid cancer or thyroid disease.

Blood Tests

There is no blood test that can detect thyroid cancer. Still, your doctor may want you to get one to help figure out whether your thyroid gland is working right.

Genetic Tests

Based on your family history, your doctor might order genetic testing to find out if you have any genes that make you more likely to get cancer. It can also show genetic changes that could be a sign of certain types of thyroid cancer.


If you have a thyroid lump, you may need to have it tested. A biopsy will tell if it’s cancer or not.

To do a biopsy, your doctor uses a small, thin needle to take a little sample from the lump, and maybe other places around it.

You’ll probably get this “fine-needle biopsy” in your doctor’s office. You won’t need any recovery time afterward.

After they get the sample, the doctor will send the sample to a lab for testing.


An ultrasound helps your doctor learn more about the thyroid nodule(s). It uses high-frequency sound waves to create an image of your thyroid.

Your doctor will place a small device that looks like a wand in front of your thyroid gland. The image of your thyroid and any nodules, even those you can’t feel, will show up on a computer screen.

An ultrasound may show your doctor if a lump is filled with fluid or if it’s solid. A solid one is more likely to have cancerous cells, but you’ll still need more tests to find out. The ultrasound will also show the size and number of nodules on your thyroid.

Radioiodine Scan

This test uses radioactive iodine which will be taken up by thyroid cells. A scan measures radiation in the thyroid or other parts of the body.

CT Scan

Computed tomography, commonly called a CT scan or CAT scan, uses special X-rays to give your doctor a look inside of your body. It can show the size and location of thyroid cancer and whether it has spread to other parts of your body.

PET Scan

Your doctor might recommend a positron emission tomography, or PET scan. This test uses small amounts of radioactive material, called radiotracers, a special camera, and a computer to look at your organs and tissue.

A PET scan looks at changes on the cellular level. It may be able to detect the cancer in a very early state and check for cancer spread.

Your doctor will give you the results of your tests.


Act Fast

Remember that the odds are the lump on your neck probably isn’t thyroid cancer, but you’re doing the right thing to get it checked out. And if it is, the sooner you find out and start treatment, the better.

Show Sources


National Cancer Institute: “A Snapshot of Thyroid Cancer.”

Endocrine Practice, “The Increasing Incidence of Thyroid Cancer.”

American Thyroid Association: “Thyroid Cancer.”

Light of Life Foundation: “Thyroid Cancer Q&A.”

Mayo Clinic: “Thyroid cancer.”

Radiological Society of North America, Inc.: “Ultrasound-Thyroid.”

East Jefferson Imaging Center: “Q&A: About Your CT Scan.”

PET Professional Resources and Outreach Source: “PET Scans: Get the Facts.”

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