Thyroid Cancer: Tests After Diagnosis

After a diagnosis of thyroid cancer, you will likely have other tests. These tests help your healthcare providers learn more about the cancer. They can help show if the cancer has grown into nearby areas or spread to other parts of the body. The test results help your healthcare providers decide the best ways to treat the cancer. If you have any questions about these or other tests, be sure to talk with your healthcare team.

The tests you have may include:

• Blood tests

• Imaging tests

A variety of blood tests will be used before, during, and after diagnosis and treatment. They are used to see if the thyroid gland is making hormones, and to check your overall health. These tests may include:

• Thyroid hormone levels. This test is used to check the level of the thyroid hormones, T3 (triiodothyronine) and T4 (thyroxine), in your body.

• TSH (thyroid-stimulating hormone) level. This test measures the level of this hormone that is produced by the pituitary gland in the brain. This hormone stimulates the thyroid to make its own hormones, T3 and T4.

• Thyroglobulin . This test measures the level of this protein that's made by the thyroid gland and differentiated thyroid (papillary and follicular) cancer.

• Thyroglobulin antibodies. This test measures the level of antibodies against the thyroid enzyme in your body. It will give data to your healthcare provider on the real amount of thyroglobulin.
• Calcitonin and CEA (carcinoembryonic antigen). Levels are checked to watch for medullary thyroid cancer growth or return after treatment.

The overall goal of treatment is to destroy all thyroid cancer cells. Depending on your type of tumor and whether all or part of your thyroid was removed, the levels of some of these hormones and proteins should drop and then stay very low after treatment.

These tests may be used after diagnosis to help see if the thyroid cancer has spread or come back after treatment

• Radionuclide or radioiodine scan. A very small, harmless amount of radioactive iodine called a radiotracer is swallowed or put in a vein. Over time, it’s absorbed by thyroid cells, no matter where they are in your body. The thyroid cells can then easily be seen on the body scan taken several hours later.

• Neck ultrasound. High-energy sound waves are bounced off structures or tissues in the neck to form a picture.

• Chest X-ray.A regular chest X-ray may be used to see if the cancer has spread to your lungs.

• CT scan. This test uses X-rays to get detailed cross-sectional images of the body. It can be used to find out if the cancer has spread to other parts of your body. A contrast agent is often either put in a vein or swallowed to help make the detailed images clearer.

• PET scan. If the thyroid cancer doesn't absorb iodine, this test may be used to look for cancer all over the body. Instead of iodine, an IV radioactive sugar is given into a vein. It collects in the cancer cells over time. A scan is done to look for it. This test is often combined with a CT scan to give detailed pictures of any tumors that use a lot of the sugar.

• Laryngoscopy. In this procedure, the healthcare provider checks your voice box, or larynx, to see if the thyroid tumor is pressing on your vocal cords. This can be done with special mirrors. Or the provider may use a very thin, flexible tube called a laryngoscope. This tube has a light and a lens on it. The provider can look through the lens and see how well the vocal cords are moving.

Your healthcare provider will talk with you about which tests you'll have. Make sure to get ready for the tests as instructed. Ask questions and talk about any concerns you have.