Stages of Cancer

Approved by the Lineagotica Editorial Board, 03/2018

Staging helps describe where a cancer is located, if or where it has spread, and whether it is affecting other parts of the body. Doctors often use diagnostic tests to determine a cancer’s stage. Staging may not be complete until all of these tests are finished. Knowing the stage helps the doctor:

  • Plan treatment, including the type of surgery and/or whether chemotherapy or radiation therapy are needed

  • Predict the chance that the cancer will come back after the original treatment

  • Predict the chance of recovery

  • Talk about the diagnosis in a clear, common language with the entire health care team

  • Determine how well the treatment worked

  • Compare how well new treatments work among large groups of people with the same diagnosis

About the TNM staging system

For many types of cancer, doctors commonly use the TNM system of the American Joint Committee on Cancer (AJCC) to describe a cancer’s stage. Doctors answer the following questions based on the results from diagnostic tests, imaging scans, and surgery to remove or get a sample of the tumor.

  • How large is the primary tumor? Where is it located? (Tumor, T)

  • Has the tumor spread to the lymph nodes? If so, where and how many? (Node, N)

  • Has the cancer spread to other parts of the body? If so, where and how much? (Metastasis, M)

  • Are there any biomarkers or tumor markers linked to the cancer that may make it more or less likely to spread?

Staging can be “clinical” or “pathological.” Clinical staging is based on the results of tests done before surgery, such as physical examinations and imaging scans. Pathological staging is based on what is found during surgery. Clinical stage is often indicated with a lowercase “c” before the TNM classification. The pathological stage is indicated with a lowercase “p.” In general, pathological staging provides the most information to determine a patient’s prognosis.

Staging may also be done after a person has received other treatments before surgery, such as radiation therapy, chemotherapy, hormone therapy, or immunotherapy. This is called post-therapy stage. This type of staging may be done for some cancers because treatment before surgery helps shrink the tumor so it can be removed. Post-therapy stage is indicated with a lowercase “y” before the TNM classification.

TNM descriptions

Listed below are the general descriptions of the TNM staging system. However, the specific definitions for each category are different for each type of cancer that is staged using this system. Learn more specific staging information for each type of cancer.

  • Tumor (T). The letter "T" plus a number (0 to 4) describes the size and location of the tumor, including how much the tumor has grown into nearby tissues. Tumor size is measured in centimeters (cm). A centimeter is roughly equal to the width of a standard pen or pencil. A larger tumor or a tumor that has grown more deeply into the surrounding tissue receives a higher number. For some types of cancer, lowercase letters, such as “a,” “b,” or "m" (for multiple), are added to the “T” category to provide more detail.

  • Node (N). The letter "N" plus a number (0 to 3) stands for lymph nodes. These tiny, bean-shaped organs help fight infection. Lymph nodes near where the cancer started are called regional lymph nodes. Lymph nodes in other parts of the body are called distant lymph nodes. Most often, the more lymph nodes with cancer, the larger the number assigned. However, for some tumors, the location of the lymph nodes with cancer may determine the “N” category.

  • Metastasis (M). The letter "M" indicates whether the cancer has spread to other parts of the body, called distant metastasis. If the cancer has not spread, it is labeled M0. If the cancer has spread, it is considered M1.

Other factors included in the stage

In addition to the TNM categories, other factors may be included in the stage depending on the specific type of cancer. These may include:

  • Grade. The grade describes how much cancer cells look like healthy cells when viewed under a microscope. This may be indicated with the use of the letter “G” and a number (0 to 4). The doctor compares the cancerous tissue with healthy tissue. Healthy tissue usually contains many different types of cells grouped together. If the cancer looks similar to healthy tissue and contains different cell groupings, it is called “differentiated” or a “low-grade tumor.” If the cancerous tissue looks very different from healthy tissue, it is called “poorly differentiated” or a “high-grade tumor.” The cancer’s grade may help the doctor predict how quickly the cancer will spread. In general, the lower the tumor’s grade, the better the prognosis. Different types of cancer have different methods to assign a cancer grade.

  • Tumor markers or biomarkers. Tumor markers, or biomarkers, are substances found at higher than normal levels on the surface of cancer cells or in the blood, urine, or body tissues of some people with cancer. For many types of cancer, tumor markers can help figure out how likely the cancer is to spread and determine the best treatment options. For some cancers, certain tumor markers may be more helpful than stage in helping plan treatment. Learn more about testing for tumor markers and about how they are used for staging in each cancer-specific section on Lineagotica.

  • Tumor genetics. Researchers have found ways to determine the genes involved in many types of cancer. Many of these genes may help predict if a specific type of cancer will spread or what treatment(s) will work best. This information may help doctors target treatment to each person’s cancer. Learn more about personalized and targeted therapies.

Cancer stage grouping

Doctors combine the T, N, M results and other factors specific to the cancer to determine the stage of cancer for each person. Most types of cancer have four stages: stages I (1) to IV (4). Some cancers also have a stage 0 (zero).

  • Stage 0. This stage describes cancer in situ, which means “in place.” Stage 0 cancers are still located in the place they started and have not spread to nearby tissues. This stage of cancer is often highly curable, usually by removing the entire tumor with surgery.

  • Stage I. This stage is usually a small cancer or tumor that has not grown deeply into nearby tissues. It also has not spread to the lymph nodes or other parts of the body. It is often called early-stage cancer.

  • Stage II and Stage III. In general, these 2 stages indicate larger cancers or tumors that have grown more deeply into nearby tissue. They may have also spread to lymph nodes but not to other parts of the body.

  • Stage IV. This stage means that the cancer has spread to other organs or parts of the body. It may also be called advanced or metastatic cancer.

Restaging

The stage of a cancer does not change over time. If the cancer comes back or spreads to another part of the body, the more recent information about the size and spread of the cancer is added to the original stage.

Sometimes, a doctor might “restage” a cancer to determine how well a treatment is working or to get more information about a cancer that has come back after treatment. This process uses the same staging system described above. Usually some of the same tests that were done when the cancer was first diagnosed will be repeated. After this, the doctor may assign the cancer a new stage. The doctor then adds a lowercase “r” before the new stage to show that it is different from that of the first diagnosis. However, this is not common.

Other staging systems

The TNM system is mainly used to describe cancers that form solid tumors, such as breast, colon, and lung cancers. However, doctors use other staging systems to classify other types of cancer, such as:

  • Central nervous system tumors (brain tumors). Because cancerous brain tumors do not normally spread outside the brain and spinal cord, only the "T" description of the TNM system applies. Currently, no single staging system exists for central nervous system tumors. Learn more about brain tumor staging and prognostic factors.

  • Childhood cancers. The AJCC does not include childhood cancers in its staging system. Doctors stage most childhood cancers separately according to other staging systems that are often specific to the type of cancer.

  • Cancers of the blood. The TNM system does not describe leukemia, lymphoma, or multiple myeloma since they usually do not form solid tumors. Each blood cancer has a unique staging system.

Related Resources

Cancer Stage: 5 Important Reasons to Know Yours

Tests and Procedures

Reading a Pathology Report

After a Biopsy: Making the Diagnosis