After mycosis fungoides and the Sézary syndrome have been diagnosed, tests are done to find out if cancer cells have spread from the skin to other parts of the body.

The process used to find out if cancer has spread from the skin to other parts of the body is called staging. The information gathered from the staging process determines the stage of the disease. It is important to know the stage in order to plan treatment. The following procedures may be used in the staging process:

• Chest x-ray : An x-ray of the organs and bones inside the chest. An x-ray is a type of energy beam that can go through the body and onto film, making a picture of areas inside the body.

• CT scan (CAT scan): A procedure that makes a series of detailed pictures of areas inside the body, such as the lymph nodes, chest, abdomen, and pelvis, taken from different angles. The pictures are made by a computer linked to an x-ray machine. A dye may be injected into a vein or swallowed to help the organs or tissues show up more clearly. This procedure is also called computed tomography, computerized tomography, or computerized axial tomography.

• MRI (magnetic resonance imaging): A procedure that uses a magnet, radio waves, and a computer to make a series of detailed pictures of areas inside the body, such as the lymph nodes, chest, abdomen, and pelvis. This procedure is also called nuclear magnetic resonance imaging (NMRI).

• PET scan (positron emission tomography scan): A procedure to find malignant tumor cells in the body. A small amount of radioactive glucose (sugar) is injected into a vein. The PET scanner rotates around the body and makes a picture of where glucose is being used in the body. Malignant tumor cells show up brighter in the picture because they are more active and take up more glucose than normal cells do.

• Lymph node biopsy : The removal of all or part of a lymph node. A pathologist views the tissue under a microscope to look for cancer cells.

There are three ways that cancer spreads in the body.

The three ways that cancer spreads in the body are:

• Through tissue. Cancer invades the surrounding normal tissue.
• Through the lymph system. Cancer invades the lymph system and travels through the lymph vessels to other places in the body.
• Through the blood. Cancer invades the veins and capillaries and travels through the blood to other places in the body.

When cancer cells break away from the primary (original) tumor and travel through the lymph or blood to other places in the body, another (secondary) tumor may form. This process is called metastasis. The secondary (metastatic) tumor is the same type of cancer as the primary tumor. For example, if breast cancer spreads to the bones, the cancer cells in the bones are actually breast cancer cells. The disease is metastatic breast cancer, not bone cancer.

The following stages are used for mycosis fungoides and the Sézary syndrome:

Stage I

Stage I is divided into stage IA and stage IB as follows:

• Stage IA: Less than 10% of the skin surface is covered with patches, papules, and/or plaques.

• Stage IB: Ten percent or more of the skin surface is covered with patches, papules, and/or plaques.

There may be abnormal lymphocytes in the blood but they are not cancerous.

Stage II

Stage II is divided into stage IIA and stage IIB as follows:

• Stage IIA: Any amount of the skin surface is covered with patches, papules, and/or plaques. Lymph nodes are enlarged but cancer has not spread to them.

• Stage IIB: One or more tumors that are 1 centimeter or larger are found on the skin. Lymph nodes may be enlarged but cancer has not spread to them.

There may be abnormal lymphocytes in the blood but they are not cancerous.

Stage III

In stage III, nearly all of the skin is reddened and may have patches, papules, plaques, or tumors. Lymph nodes may be enlarged but cancer has not spread to them.

There may be abnormal lymphocytes in the blood but they are not cancerous.

Stage IV

Stage IV is divided into stage IVA and stage IVB as follows:

• Stage IVA: Most of the skin is reddened and any amount of the skin surface is covered with patches, papules, plaques, or tumors, and either:
  • cancer has spread to lymph nodes and there may be cancerous lymphocytes in the blood; or
  • there are cancerous lymphocytes in the blood and lymph nodes may be enlarged, but cancer has not spread to them.

• Stage IVB: Most of the skin is reddened and any amount of the skin surface is covered with patches, papules, plaques, or tumors. Cancer has spread to other organs in the body. Lymph nodes may be enlarged and cancer may have spread to them. There may be cancerous lymphocytes in the blood.