Staging of Cancer

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KEY POINTS

• Cancer staging describes how advanced the cancer is at the time of diagnosis. Staging helps your healthcare provider plan your treatment and helps give an idea of your chances for a cure.
• Staging is based on the way cancer develops and spreads. Grading is based on how the cancer cells look compared with normal cells in the same part of the body.
• Some cancers do not follow these staging systems. Talk with your healthcare provider and ask questions about staging and grading.

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What is cancer?

Cancer is a growth of abnormal cells. There are different names for cancer that are related to where the cancer started in the body

• Cancers that start in the tissue that lines the inner or outer surfaces of the body, such as the skin, the uterus, the lung, or the breast are called carcinomas.
• Cancers of supportive or connective tissue, such as muscle or bone, are known as sarcomas.
• Cancers of lymph tissue, bone marrow, and blood cells are called leukemias, lymphomas, and myelomas.
• Cancers of brain tissues are called gliomas.
• The serious type of skin cancer is called melanoma.

What is cancer staging?

Staging describes how advanced the cancer is at the time of diagnosis. Knowing the stage of the disease helps your healthcare provider plan your treatment and helps give an idea of your chances for a cure.

Staging is based on the way cancer develops and spreads. Cancer cells divide and grow without control to form a tumor. As the tumor grows, it can spread to nearby organs and tissues. The spread of cancer cells from one part of the body to other parts is called metastasis. What causes cancer to spread is not known. Cancer cells can:

• Grow into the area around the tumor
• Travel to other parts of the body through the bloodstream or the lymph system. The lymph system is part of your body's system for fighting infection. The lymph system consists of lymph nodes that store blood cells (lymphocytes) to fight infection and vessels that carry fluid, nutrients, and wastes between your body and your bloodstream.

New tumors then grow in these other areas.

How is cancer staged?

It is important to understand that the stage applies ONLY to your condition at the time cancer is diagnosed. Staging may be based on a physical exam, X-rays, a biopsy, or surgery.

The stage is usually based on the size of the original tumor and how far the cancer has spread. The higher the stage, the more cancer cells, and the more widespread the cancer is.

• Stage 0: Early cancer (carcinoma in situ) is present only in the layer of cells in which it began. It has not spread and it is curable. It can be thought of as precancer.
• Stages I, II, and III: These higher numbers may mean that the original tumor is bigger than stage 0, that the cancer has spread to nearby lymph nodes, or that it has spread to organs next to the original tumor.
• Stage IV: The cancer has spread to another part of your body.

Another staging system is called TNM (Tumor, Nodes, Metastasis). This system measures the size of the tumor, the number of nearby lymph nodes that contain cancer, and how far the cancer has spread, or metastasized. The TNM system can give a single stage number that is unique to each cancer.

Some cancers such as lymphoma and leukemia do not follow these staging systems. Talk with your healthcare provider about this.

Grade is based on how the cancer cells look compared with normal cells in the same part of the body. The grade of a tumor depends on how abnormal the cancer cells look under a microscope and may help to determine how quickly the tumor is likely to grow and spread. Grading systems are different for each type of cancer.

Besides the size of the tumor and whether the cancer has spread to lymph nodes or other parts of the body, your healthcare provider will also look at:

• Whether certain proteins are present in cancer cells
• What kind of genetic changes are present the cancer cells. Genes are inside each cell of your body. They contain the information that tells your body how to develop and work.
• Tumor markers, which are substances that are produced by cancer or by other cells of the body in response to cancer
• Tumor grades, which range from almost normal to most abnormal

All of these things help give an idea of your chances for successful treatment when you are diagnosed, and later in the treatment process.