If your doctor thinks that you may have thyroid cancer, you’ll have one or more of the following tests:
- Physical exam: Your doctor feels your thyroid for lumps (nodules). Your doctor also checks your neck and nearby lymph nodes for growths or swelling.
- Blood tests: Your doctor may check for abnormal levels of thyroid-stimulating hormone (TSH) in the blood. Too much or too little TSH means the thyroid is not working well. If your doctor thinks that you may have medullary thyroid cancer, you’ll be checked for a high level of calcitonin and have other blood tests.
- Ultrasound: An ultrasound device uses sound waves that can’t be heard by humans. The sound waves make a pattern of echoes as they bounce off organs inside your neck. The echoes create a picture of your thyroid and nearby tissues. The picture can show thyroid nodules that are too small to be felt. Your doctor uses the picture to learn the size and shape of each nodule and whether the nodules are solid or filled with fluid. Nodules that are filled with fluid are usually not cancer. Nodules that are solid may be cancer.
- Thyroid scan: Your doctor may order a scan of your thyroid. You swallow a small amount of a radioactive substance (such as radioactive iodine), and it travels through the bloodstream. Thyroid cells that absorb the radioactive substance can be seen on a scan. Nodules that take up more of the substance than the thyroid tissue around them are called “hot” nodules. Hot nodules are usually not cancer. Nodules that take up less substance than the thyroid tissue around them are called “cold” nodules. Cold nodules may be cancer.
- Biopsy: A biopsy is the only sure way to diagnose thyroid cancer. A pathologist checks a sample of thyroid tissue for cancer cells using a microscope.
Your doctor may take tissue for a biopsy in one of two ways:
- With a thin needle: Your doctor removes a sample of tissue from a thyroid nodule with a thin needle. An ultrasound device can help your doctor see where to place the needle. Most people have this type of biopsy.
- With surgery: If a diagnosis can’t be made from tissue removed with a needle, a surgeon removes a lobe or the entire thyroid. For example, if the doctor suspects follicular thyroid cancer, the lobe that contains the nodule may be removed for diagnosis.
You may want to ask the doctor these questions before having a biopsy:
- Will I have to go to the hospital?
- How long will it take? Will I be awake? Will it hurt?
- Are there any risks? What is the chance of infection or bleeding afterward?
- Will I have a scar on my neck?
- How soon will I know the results? Who will explain them to me?
- If I do have cancer, who will talk to me about the next steps? When?