If the biopsy shows that you have cancer, your doctor will need to learn the extent (stage) of the disease to help you choose the best treatment.
The stage is based on the size of the nodule and whether the cancer has invaded nearby tissues or spread to other parts of the body. Thyroid cancer spreads most often to nearby tissues in the neck or to lymph nodes. It may also spread to the lungs and bones.
When cancer spreads from its original place to another part of the body, the new tumor has the same kind of cancer cells and the same name as the original tumor. For example, if thyroid cancer spreads to the lungs, the cancer cells in the lungs are actually thyroid cancer cells. The disease is metastatic thyroid cancer, not lung cancer. It’s treated as thyroid cancer, not as lung cancer. Doctors sometimes call the new tumor in the lung “distant” disease.
Staging may involve one or more of these tests:
- Ultrasound: An ultrasound exam of your neck may show whether cancer has spread to lymph nodes or other tissues near your thyroid.
- CT scan: An x-ray machine linked to a computer takes a series of detailed pictures of your neck and chest area. A CT scan may show whether cancer has spread to lymph nodes, other areas in your neck, or your chest.
- MRI: MRI uses a powerful magnet linked to a computer. It makes detailed pictures of your neck and chest area. MRI may show whether cancer has spread to lymph nodes or other areas.
- Chest x-ray: An x-ray of the chest can often show whether cancer has spread to the lungs.
- Whole body scan: You may have a whole body scan to see if cancer has spread from the thyroid to other parts of the body. You get a small amount of a radioactive substance (such as radioactive iodine). The substance travels through the bloodstream. Thyroid cancer cells in other organs or the bones take up the substance. Thyroid cancer that has spread may show up on a whole body scan.