Key Messages:

• Staging is used to help plan treatment and predict a person’s chance of recovery.
  
  
• Stage is usually determined by three factors: size and growth of the tumor, whether cancer is located in lymph nodes, and whether it has spread to other parts of the body.
  
  
• Other factors, such as grade, tumor markers, and tumor genes, may be used to help describe the cancer in more detail.

Staging is a way of describing a cancer, such as where it is located, if or where it has spread, and if it is affecting the functions of other organs in the body. Doctors use diagnostic tests to determine the cancer’s stage, so staging may not be complete until all the tests are finished. Knowing the stage helps the doctor:

• Plan treatment
  
  
• Predict prognosis (chance of recovery)
  
  
• Talk about the diagnosis in a clear, common language with the cancer treatment team
  
  
• Interpret treatment effectiveness
  
  
• Analyze larger populations with the same diagnosis as part of cancer research to evaluate new, more effective treatments

The staging system used by doctors is the TNM system from the American Joint Committee on Cancer (AJCC). TNM is an abbreviation for tumor (T), node (N), and metastasis (M), or cancer that has spread to other areas of the body. The TNM system uses three criteria to describe the stage of the cancer: the tumor itself, the lymph nodes around the tumor, and if the tumor has spread to other parts of the body. The results are combined to determine the stage of cancer for each person. There is a separate TNM system for each type of cancer. Below are general descriptions of the TNM staging system. Learn more about detailed staging for each type of cancer.

T: The letter "T" plus a letter and a number (0 to 4) is used to describe the size of the tumor, including how much the tumor has grown into the nearby tissue. A larger tumor or a tumor that has grown more deeply into the surrounding tissue is given a larger number.

N: The letter "N" plus a number (0 to 3) describes whether there is cancer in the lymph nodes, and, in some types of cancer, how many of these lymph nodes contain cancer. Lymph nodes are the tiny, bean-shaped organs that help fight infection. Lymph nodes near the site of the cancer 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. For other tumors, the location of the nodes that have cancer may determine the N rating.

M: The letter "M" indicates whether the cancer has metastasized (spread) to other parts of the body from where it started. Each cancer is assigned either M0, meaning the cancer has not spread to other parts of the body, or M1, meaning the cancer has spread to other parts of the body.

For some cancers, the TNM categories are divided even more by using lowercase letters. For example, the letter “m” may be used if there is more than one tumor. It is important to talk with your doctor about the stage of your cancer and what it means for your diagnosis and treatment.

Other information about the cancer may also be used to determine the stage. This includes the results of blood tests and specific tests that are done on the cancer tissue itself.

Cancer stage grouping

Doctors assign the stage of cancer by combining the T, N, and M classifications. Most cancers have four stages, stages I to IV. Some cancers also have a stage 0 (zero).

Stage 0. This is used to describe cancer in situ, meaning that the cancer is still near the place it started and has not invaded nearby tissues. It is often highly curable.

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

Stage II and III. These stages indicate cancers or tumors that are larger in size, have grown more deeply into nearby tissue, and have 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 be called advanced cancer.

In addition to the T, N, and M staging system, your doctor may use other information about a cancer to help determine the prognosis and the best available treatment. For some cancers, this information is used in addition to T, N, and M to determine the stage group.

Grade. The grade describes how the cancer cells look under a microscope when compared with healthy cells. The grade of a cancer can help the doctor predict how quickly the cancer will spread. A tumor with cells that look more like healthy cells is called well differentiated or low-grade. A tumor with cells that look less like healthy cells, or “wilder” is poorly differentiated or undifferentiated and is called high-grade. In general, the prognosis is better for a tumor with cells that look more like healthy cells. There are different methods used to assign a cancer grade for different types of cancers. For example, prostate cancer uses a grading system called the Gleason System that assigns a score on the tissue sample.

Tumor markers. Tumor markers are substances found at higher than normal levels in the blood, urine, or body tissues of some people with cancer. For some cancers, certain tumor markers may be more helpful than stage to predict the chance that the cancer will spread or to choose the best treatment. One example of a tumor marker is the estrogen receptor in breast cancer. Read more about tumor markers for breast cancer. Doctors and researchers have been discovering tumor markers for many types of cancer that can help determine the best treatment. Learn more about tumor markers for specific cancers.

Tumor genetics. There are many genes in cancers that may help understand if the cancer will spread or what treatment will be effective. Recent research studies have found ways to determine the genes involved in a type of cancer. In the future, this information may also help doctors target treatment to each person’s cancer.

Other Staging Systems

The TNM system is used to describe most cancers that form solid tumors like breast, colon, and lung cancers. In addition to TNM staging, there are other staging systems used to classify other types of cancer. Examples of these types of cancers include:

Central nervous system tumors (brain cancers). Because cancerous brain tumors do not normally spread outside of the central nervous system (CNS, brain and spinal cord), only the "T" description of the TNM system applies. Currently, there is not one single staging system for central nervous system tumors.

Childhood cancers. The AJCC does not include childhood cancers in its staging system. Most childhood cancers are staged separately, according to other staging systems that are often specific to the type of cancer.

Leukemias and Lymphomas. Cancers of the blood are not described by the TNM system, since they usually do not form solid tumors. A leukemia is described according to subtypes and by how the cancer cells differ between types of leukemias. A lymphoma is described using four stages that are based on the following: the number and location of lymph nodes that contain cancer cells; whether the lymph nodes that contain cancer cells are on one or both sides of the diaphragm; and, whether the cancer has spread to the bone marrow, spleen, or organs outside the lymphatic system, such as the liver, lungs, or brain.

More Information

Tests and Procedures

All About Cancer

Last Updated: May 03, 2010