Hanadi BuAli, MD, FACS, FSSO, breast surgical oncologist and director of the Breast Health program for Ascension Wisconsin.
Learn more about cancer staging numbers
Being diagnosed with cancer can leave you with questions. We’re here to answer them—big and small. One question many people have is about the stages of cancer. Your stage of cancer is one of the first things you learn about when you are diagnosed. Staging a cancer can give your doctor information on how far the cancer has spread, how you may fare and what type of treatment you may need.
If a cancer is diagnosed early, it is usually located in one area of your body. That can make it easier to remove with surgery and/or radiation. Cancer presenting at a later stage means that it has spread to other areas of your body, may require adding chemotherapy and would likely need a longer time for treatment.
The TNM staging system
The most common cancer staging system is called the TNM classification system. Your cancer team will assign letters and numbers to the cancer to describe the tumor size/depth (T), lymph nodes (N), and whether the cancer has spread to other areas (M).
Tumor
The T category in TNM provides information about the tumor size, where it started, and if it has invaded surrounding tissue.
- TX means the tumor cannot be measured
- T0 means the tumor cannot be found
- Tis means the cancer is growing only in the most superficial layer of tissue (this is usually true with Stage 0 or cancer that has not spread)
- T1-T4 describes the size of the tumor and the extent to which it has spread to nearby tissue. The higher the number after the T, the larger the tumor or involvement of surrounding tissue.
Lymph nodes
The N category describes whether the cancer has spread to the lymph nodes.
- NX means the nearby lymph nodes cannot be evaluated
- N0 means nearby lymph nodes do not contain cancer
- N1-N3 describes the size, location, and the number of nearby lymph nodes affected by the cancer
Metastasis
The M category describes whether the cancer has spread to other parts of the body.
- MX means that metastasis cannot be measured
- M0 means that the cancer has not spread widely to other areas. Involvement of the lymph nodes in the immediate area to the cancer still qualifies as M0 disease
- M1 means that the cancer has spread to distant organs or tissue
New Cancer staging system
In addition to the TNM classification mentioned above, the new cancer staging system for some tumors includes markers that can give us some information about the biology of the cancer such as the grade and various other receptors (tags) in the tumor cells. For example, in the case of breast cancer, it is important for both staging and treatment to know if the cancer has receptors for estrogen.
Cancer stages 0 to IV
The number of cancer stages is different for different types of cancers. However, as a general rule, stage 0 means it is at its very early stages, is superficial and has not invaded surrounding tissue while stage IV means that it has spread to areas in the body other than the lymph nodes immediately in the area close to the cancer.
Common questions about staging
Do cancer stages change over time?
The stage of cancer you start with does not change after you receive treatment unless it starts spreading. For example, if you were diagnosed with stage II lung cancer and went into remission, that does not mean you go to a lower stage. However, if the disease continues to spread, it can be given a higher cancer stage.
Do people with the same stage of cancer receive similar treatment?
Not all cancers at the same stage have the same type of treatment. For example, the treatment of stage II breast cancer is not the same as that for stage II colon cancer. Also, the same types of cancers at the same stage might not necessarily have the same type of treatment. For example, if you and another person both have stage II breast cancer, you might not necessarily have the same treatment. Your treatment is personalized based on the type of your cancer, biology of your disease and your general health.
Understanding your cancer stage can be helpful but if you have questions, you should always discuss your diagnosis in depth with your doctor. Learn more about cancer care treatment at Ascension sites of care in Wisconsin.