Skin Cancer Staging

If the biopsy shows that you have skin cancer you will be referred to a cancer specialist, known as an oncologist. Whether melanoma or nonmelanoma skin cancer, your oncologist needs to know the extent (stage) of the disease. Staging is a careful attempt to learn how thick the tumor is, and if it has spread. 

Knowing the stage of your cancer helps your cancer doctor:

• Understand how serious your cancer is and your chances of survival
• Plan the best treatment for you
• Identify clinical trials that may be treatment options for you

In some cases, the oncologist may check your lymph nodes to stage the cancer (such surgery may be considered part of the treatment because removing cancerous lymph nodes may help control the disease).

The stage of the skin cancer is based on:

• The size of the growth
• How deeply it has grown beneath the top layer of skin
• Whether it has spread to nearby lymph nodes or to other parts of the body

Tests Used to Stage Skin Cancers

If the tumor is thick, the doctor may order tests to determine if the cancer has spread to other parts of the body. The tests used to stage melanoma or nonmelanoma skin cancer include:

• X-ray of the chest to see if the cancer has spread to the lungs.
• CT scan to see if the cancer has spread to other organs, such as the liver.
• MRI to see if the cancer has spread to the brain or spinal cord.
• PET scan to see if the cancer has spread elsewhere.
• Nuclear bone scans to see if the cancer has spread to the bones.
• Fine needle aspiration biopsy in which the physician uses a thin needle to remove very small samples of tissue from organs or lymph nodes.
• Surgical lymph node biopsy to remove an abnormally large lymph node through a small incision.
• Sentinel lymph node biopsy, the surgeon injects a radioactive substance into the area of the melanoma, then checks the lymph nodes for radioactivity to find which one is the first to drain fluid from the skin near the melanoma. Then the lesion is injected with a blue dye that will travel to the node that the cancer would first drain into. When this first node, called the sentinel node, had been identified, it will be removed and looked at under a microscope. If cancer cells are found in this lymph node, the rest of the lymph nodes in the area are removed.

Oncologists use the Roman numerals I through IV to indicate the stage of a patient’s cancer. Stage I cancers are small and limited to the area where they began. Stage IV indicates advanced cancer that has spread to other areas of the body.

Nonmelanoma Skin Cancer Staging

These are the stages of skin cancer:

• Stage 0: The cancer involves only the top layer of skin. It is carcinoma in situ.
• Stage I: The growth is 2 centimeters wide (three-quarters of an inch) or smaller.
• Stage II: The growth is larger than 2 centimeters wide (three-quarters of an inch).
• Stage III: The cancer has spread below the skin to cartilage, muscle, bone, or to nearby lymph nodes. It has not spread to other places in the body.
• Stage IV: The cancer has spread to other places in the body.

Melanoma Staging

The following stages are used for melanoma:

• Stage 0: In stage 0, the melanoma cells are found only in the outer layer of skin cells and have not invaded deeper tissues.
• Stage I: Melanoma in stage I is thin:
  • The tumor is no more than 1 millimeter (1/25 inch) thick. The outer layer (epidermis) of the skin may appear scraped. (This is called an ulceration).
  • Or, the tumor is between 1 and 2 millimeters (1/12 inch) thick. There is no ulceration. The melanoma cells have not spread to nearby lymph nodes.
• Stage II: The tumor is at least 1 millimeter thick:
  • The tumor is between 1 and 2 millimeters thick. There is ulceration.
  • Or, the thickness of the tumor is more than 2 millimeters. There may be ulceration. The melanoma cells have not spread to nearby lymph nodes.
• Stage III: The melanoma cells have spread to nearby tissues:
  • The melanoma cells have spread to one or more nearby lymph nodes.
  • Or, the melanoma cells have spread to tissues just outside the original tumor but not to any lymph nodes.
• Stage IV: The melanoma cells have spread to other organs, to lymph nodes, or to skin areas far away from the original tumor.
• Recurrent: Recurrent disease means that the cancer has come back (recurred) after it has been treated. It may have come back in the original site or in another part of the body.