Stages of Melanoma

Cancer stage describes the extent of cancer in the body, such as the size of the tumor, whether it has spread, and how far it has spread from where it first formed. It is important to know the melanoma stage to plan treatment.

There are several staging systems for cancer that describe the extent of the cancer. Melanoma staging usually uses the TNM staging system. The cancer may be described by this staging system in your pathology report. Based on the TNM results, a stage (I, II, III, or IV, also written as 1, 2, 3, or 4) is assigned to your cancer. When talking to you about your diagnosis, your doctor may describe the cancer as one of these stages.

Learn about tests to stage melanoma. Learn more about Cancer Staging.

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 tumor's thickness, which 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), digestive tract, and/or distant lymph nodes.

The following stages are used for melanoma:

Stage 0 (melanoma in situ)

In stage 0, abnormal melanocytes are found in the epidermis. These abnormal melanocytes may become cancer and spread into nearby normal tissue. Stage 0 is also called melanoma in situ.

Stage I (also called stage 1) melanoma

In stage I, cancer has formed. Stage I is divided into stages IA and IB.

• Stage IA: The tumor is not more than 1 millimeter thick, with or without ulceration.
• Stage IB: The tumor is more than 1 but not more than 2 millimeters thick, without ulceration.

Stage II (also called stage 2) melanoma

Stage II is divided into stages IIA, IIB, and IIC.

• Stage IIA: The tumor is either:
  • more than 1 but not more than 2 millimeters thick, with ulceration; or
  • more than 2 but not more than 4 millimeters thick, without ulceration.
• Stage IIB: The tumor is either:
  • more than 2 but not more than 4 millimeters thick, with ulceration; or
  • more than 4 millimeters thick, without ulceration.
• Stage IIC: The tumor is more than 4 millimeters thick, with ulceration.

Stage III (also called stage 3) melanoma

Stage III is divided into stages IIIA, IIIB, IIIC, and IIID.

• Stage IIIA: The tumor is not more than 1 millimeter thick, with ulceration, or not more than 2 millimeters thick, without ulceration. Cancer is found in 1 to 3 lymph nodes by sentinel lymph node biopsy.
• Stage IIIB:

  (1) It is not known where the cancer began or the primary tumor can no longer be seen, and one of the following is true:

  • cancer is found in 1 lymph node by physical exam or imaging tests; or
  • there are microsatellite tumors, satellite tumors, and/or in-transit metastases on or under the skin.

    or

  (2) The tumor is not more than 1 millimeter thick, with ulceration, or not more than 2 millimeters thick, without ulceration, and one of the following is true:

  • cancer is found in 1 to 3 lymph nodes by physical exam or imaging tests; or
  • there are microsatellite tumors, satellite tumors, and/or in-transit metastases on or under the skin.

    or

  (3) The tumor is more than 1 but not more than 2 millimeters thick, with ulceration, or more than 2 but not more than 4 millimeters thick, without ulceration, and one of the following is true:

  • cancer is found in 1 to 3 lymph nodes; or
  • there are microsatellite tumors, satellite tumors, and/or in-transit metastases on or under the skin.

• Stage IIIC:

  (1) It is not known where the cancer began, or the primary tumor can no longer be seen. Cancer is found:

  • in 2 or 3 lymph nodes; or
  • in 1 lymph node and there are microsatellite tumors, satellite tumors, and/or in-transit metastases on or under the skin; or
  • in 4 or more lymph nodes, or in any lymph nodes that are matted together; or
  • in 2 or more lymph nodes and/or in any lymph nodes that are matted together. There are microsatellite tumors, satellite tumors, and/or in-transit metastases on or under the skin.

    or

  (2) The tumor is not more than 2 millimeters thick, with or without ulceration, or not more than 4 millimeters thick, without ulceration. Cancer is found:

  • in 1 lymph node and there are microsatellite tumors, satellite tumors, and/or in-transit metastases on or under the skin; or
  • in 4 or more lymph nodes, or in any lymph nodes that are matted together; or
  • in 2 or more lymph nodes and/or in any lymph nodes that are matted together. There are microsatellite tumors, satellite tumors, and/or in-transit metastases on or under the skin.

    or

  (3) The tumor is more than 2 but not more than 4 millimeters thick, with ulceration, or more than 4 millimeters thick, without ulceration. Cancer is found in 1 or more lymph nodes and/or in any lymph nodes that are matted together. There may be microsatellite tumors, satellite tumors, and/or in-transit metastases on or under the skin.

  or

  (4) The tumor is more than 4 millimeters thick, with ulceration. Cancer is found in 1 or more lymph nodes and/or there are microsatellite tumors, satellite tumors, and/or in-transit metastases on or under the skin.

• Stage IIID: The tumor is more than 4 millimeters thick, with ulceration. Cancer is found:
  • in 4 or more lymph nodes, or in any lymph nodes that are matted together; or
  • in 2 or more lymph nodes and/or in any lymph nodes that are matted together. There are microsatellite tumors, satellite tumors, and/or in-transit metastases on or under the skin.

Stage IV (also called stage 4) melanoma

In stage IV, the cancer has spread to other parts of the body, such as the lung, liver, brain, spinal cord, bone, soft tissue (including muscle), digestive tract, and/or distant lymph nodes. Cancer may have spread to places in the skin far away from where it first started.

Stage IV melanoma is also called metastatic melanoma. Metastatic cancer happens when cancer cells travel through the lymphatic system or blood and form tumors in other parts of the body. The metastatic tumor is the same type of cancer as the primary tumor. For example, if melanoma spreads to the lung, the cancer cells in the lung are actually melanoma cells. The disease is called metastatic melanoma, not lung cancer. Learn more in Metastatic Cancer: When Cancer Spreads.

Melanoma can recur (come back) after it has been treated.

Recurrent melanoma is melanoma that has come back after it has been treated. If melanoma comes back, it may come back in the area where it first started or in other parts of the body, such as the lungs or liver. Tests will help determine where in the body the cancer has returned. The type of treatment that you have for recurrent melanoma will depend on where it has come back.

Learn more in Recurrent Cancer: When Cancer Comes Back. Information to help you cope and talk with your health care team can be found in the booklet When Cancer Returns.