Not all cancers are alike when they are first diagnosed. Sometimes there’s just a small, single tumor that can be easily removed. Other times, a tumor might be dangerously large or the cancer may have already spread to other parts of the body.
These aren’t trivial differences. The size and extent of cancers when they are first diagnosed reveal a lot of important information about treatment options and future prospects (prognosis).
What is staging?
Doctors have developed a system for describing the important details of each newly diagnosed case of cancer. A person’s breast cancer, for instance, might be described as T1 N1 M0. If you’re a cancer patient, becoming familiar with this code will help you understand your disease and your prospects.
The first thing to know about a cancer is where it started. There’s a big difference in treatment for cancer that started in the breast and cancer that started in the skin. After that, doctors can take x-rays, collect tissue samples, run blood tests, or conduct other tests to understand the size and scope of the illness. This process is called staging.
The TNM system: Tumor, lymph nodes, metastasis
Staging a solid tumor typically looks at three major factors: The size of the original tumor, whether the cancer has spread to the lymph nodes, and whether the cancer has spread to other parts of the body. Doctors call this approach the TNM system, and it’s one of the most common staging systems used. The T stands for Tumor size, the N stands for lymph Nodes, and the M stands for metastasis (the medical term for the spread of cancer throughout the body.)
T for tumor size. The size of a tumor is rated on a scale from 0 to 4. If your doctor says you have a T1 tumor, that means that the tumor is small for its type. A T4 tumor would have grown into other neighboring tissue and is often quite large for its type.
- TX: The tumor size can’t be measured
- T0: No primary tumor, or it can’t be found
- Tis: Tumor is “in situ,” meaning it is small and completely contained in the tissue where it started
- T1-4: The tumor is increasing in size and invading surrounding tissues and organs
N for lymph nodes. Lymph is the fluid between all the cells in the body. It collects and flows in lymphatic vessels, and along these vessels are small rounded organs called lymph nodes. Lymph nodes are reservoirs for cells called lymphocytes, the immune cells that produce targeted antibodies and give us long-term immunity against germs and other enemies, including cancer cells. Lymph nodes can intercept and destroy cancer cells that break free of a tumor and migrate to other areas of the body. If they fail to stop the cancer cells, the lymph nodes can end up serving as gateways to the whole body.