To plan the best treatment, your doctor needs to learn the extent (stage) of the disease. Staging is a careful attempt to find out the size of the nodule, whether the cancer has spread, and if so, to what parts of the body.
Thyroid cancer spreads most often to the lymph nodes, 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 cancer. 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. For that reason, it’s treated as thyroid cancer, not lung cancer. Doctors call the new tumor “distant” or metastatic 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 areas inside your body. 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 tissue. Your doctor can view these pictures on a screen or print them on film. MRI may show whether cancer has spread to lymph nodes or other areas.
- Chest x-ray: X-rays of your chest may 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. 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.