Risk Management & Treatment

Stages and subtypes of melanoma

After a biopsy or surgery confirms melanoma, doctors look closely at the tumor cells, size and thickness and check lymph nodes and organs for possible spread of cancer. This process is known as staging. Staging melanoma helps doctors create a plan to treat it.

Staging is done using the TNM system (tumor, node, and metastasis). TNM is based on 3 measures.

  • T (tumor) is a measure of tumor thickness and whether the tumor is ulcerated (the skin over the melanoma has broken down).
  • N (lymph node) is a measure of whether the tumor has spread to nearby lymph nodes.
  • M (metastasis) is a measure of whether the tumor has spread to other parts of the body.

Experts use numbers 0-4 to describe the stage of the cancer. Stage 0 is the earliest stage and stage 4 is the most advanced.

  • Stage 0 means the cancer is only in the top layers of skin. Stage 0 melanoma is sometimes called melanoma in situ.
  • Stagemelanomas have not spread beyond the skin, and are less than 2 millimeters (mm) thick or less than 1 mm thick but with ulceration.
  • Stage 2 melanomas have not spread beyond the skin, and are more than 2 mm thick or more than 1 mm and have not spread beyond the skin.
  • Stage 3 melanomas have spread to nearby lymph nodes or other nearby tissue.
  • Stage 4 melanomas have spread to distant lymph nodes or other organs, such as lung, liver or brain.

Additional biomarker tests can be performed on tumor samples to help guide treatment. For some patients, tumor biomarker testing can help guide the choice of targeted therapy


If you have been diagnosed with melanoma, you can find peer support through the following resources:

Other organizations that provide support for people diagnosed with melanoma include:

  • AIM at Melanoma is a nonprofit organization that has online support and a list of in-person support groups by region.