Stages of Melanoma

The stage of melanoma depends on the thickness of the tumor, whether cancer has spread to lymph nodes or other parts of the body, and other factors.

To find out the stage of melanoma, the tumor is completely removed and nearby lymph nodes are checked for signs of cancer. The stage of the cancer is used to determine which treatment is best. Check with your doctor to find out which stage of cancer you have.

The stage of melanoma depends on the following:

  • The thickness of the tumor. The thickness of the tumor is measured from the surface of the skin to the deepest part of the tumor.
  • Whether the tumor is ulcerated (has broken through the skin).
  • Whether cancer is found in lymph nodes by a physical exam, imaging tests, or a sentinel lymph node biopsy.
  • Whether the lymph nodes are matted (joined together).
  • Whether there are:
    • Satellite tumors: Small groups of tumor cells that have spread within 2 centimeters of the primary tumor.
    • Microsatellite tumors: Small groups of tumor cells that have spread to an area right beside or below the primary tumor.
    • In-transit metastases: Tumors that have spread to lymph vessels in the skin more than 2 centimeters away from the primary tumor, but not to the lymph nodes.
  • Whether the cancer has spread to other parts of the body, such as the lung, liver, brain, soft tissue (including muscle), gastrointestinal tract, and/or distant lymph nodes. Cancer may have spread to places in the skin far away from where it first formed.

Staging is the term oncologists use to define where skin cancer is located and how much it has spread. Once the stage of skin cancer is determined, your physician can recommend a particular course of treatment.

Most cancer teams use the system developed by the American Joint Committee on Cancer, known as the TNM staging system.

T = Tumor: Where is the primary tumor and how large is it?

N = Nodes: Has the tumor spread to nearby lymph nodes?

M = Metastasis: Has cancer spread to other parts of the body?

For each letter, there are five numbered stages, from 0 to 4, depending on how much the cancer has spread. The lower the number, the more the cancer cells look like normal cells and the easier they are to treat and cure. A higher number means it has spread more deeply.

The place where cancer originates is called the primary site. Cancer can spread from the primary site to other parts of the body. It's important to understand that even if skin cancer is found in other parts of your body, it's still considered skin cancer. For instance, if colon cancer has spread to the liver, it's called metastatic colon cancer, not liver cancer.

Be sure to talk to your physician about your particular stage of cancer and how that will impact your treatment.

For more information about the stages of skin cancer, please visit our Health Library.