If oral cancer is diagnosed, your doctor needs to learn the extent (stage) of the disease to help you choose the best treatment. When oral cancer spreads, cancer cells may be found in the lymph nodes in the neck or in other tissues of the neck. Cancer cells can also spread to the lungs, liver, bones, and other parts of the body.
When cancer spreads from its original place to another part of the body, the new tumor has the same kind of abnormal cells as the primary (original) tumor. For example, if oral cancer spreads to the lungs, the cancer cells in the lungs are actually oral cancer cells. The disease is called metastatic oral cancer, not lung cancer. It’s treated as oral cancer, not lung cancer. Doctors sometimes call the new tumor “distant” or metastatic disease.
Your doctor may order one or more of the following tests:
- X-rays: An X-ray of your entire mouth can show whether cancer has spread to the jaw. Images of your chest and lungs can show whether cancer has spread to these areas.
- CT scan: An X-ray machine linked to a computer takes a series of detailed pictures of your body. You may receive an injection of dye. Tumors in your mouth, throat, neck, lungs, or elsewhere in the body can show up on the CT scan.
- MRI: A powerful magnet linked to a computer is used to make detailed pictures of your body. An MRI can show whether oral cancer has spread.
- Endoscopy: The doctor uses a thin, lighted tube (endoscope) to check your throat, windpipe, and lungs. The doctor inserts the endoscope through your nose or mouth. Local anesthesia is used to ease your discomfort and prevent you from gagging. Some people also may be given a mild sedative. Sometimes the doctor uses general anesthesia to put a person to sleep. This exam may be done in a doctor’s office, an outpatient clinic, or a hospital.
- PET scan: You receive an injection of a small amount of radioactive sugar. The radioactive sugar gives off signals that the PET scanner picks up. The PET scanner makes a picture of the places in your body where the sugar is being taken up. Cancer cells show up brighter in the picture because they take up sugar faster than normal cells do. A PET scan shows whether oral cancer may have spread.
Doctors describe the stage of oral cancer based on the size of the tumor, whether it has invaded nearby tissues, and whether it has spread to the lymph nodes or other tissues:
- Early cancer: Stage I or II oral cancer is usually a small tumor (smaller than a walnut), and no cancer cells are found in the lymph nodes.
- Advanced cancer: Stage III or IV oral cancer is usually a large tumor (as big as a lime). The cancer may have invaded nearby tissues or spread to lymph nodes or other parts of the body.