Melanoma Stages

Diagnosis and Staging. What it Means for You.

How is melanoma diagnosed?

To diagnose melanoma, a dermatologist biopsies the suspicious tissue and sends it to a lab, where a dermatopathologist determines whether cancer cells are present.

After the disease is diagnosed and the type of melanoma is identified, the next step is for your medical team to identify the stage of the disease. This may require additional tests including imaging such as PET scans, CT scans, MRIs and blood tests.

The stage of melanoma is determined by several factors, including how much the cancer has grown, whether the disease has spread (metastasized) and other considerations. Melanoma staging is complex, but crucial. Knowing the stage helps doctors decide how to best treat your disease and predict your chances of recovery.

What are the melanoma stages and what do they mean?

Early Melanomas

Stage 0 and I are localized, meaning they have not spread.

  • Stage 0: Melanoma is localized in the outermost layer of skin and has not advanced deeper. This noninvasive stage is also called melanoma in situ, which means “in its original place.”
  • Stage I: The cancer is smaller than 1 mm in Breslow depth, and may or may not be ulcerated. It is localized but invasive, meaning that it has penetrated beneath the top layer into the next layer of skin. Invasive tumors, considered Stage IA, are classified as early and thin if they are not ulcerated and measure less than 0.8 mm.

Find out about treatment options for early melanomas.

Intermediate or High-Risk Melanomas

Localized but larger tumors may have other traits such as ulceration that put them at high risk of spreading.

  • Stage II: Intermediate, high-risk melanomas are tumors deeper than 1mm that may or may not be ulcerated. Although they are not yet known to have advanced, the risk of spreading is high, and physicians may recommend a sentinel lymph node biopsy to verify whether melanoma cells have spread to the local lymph nodes. Thicker melanomas, greater than 4.0 mm, have a very high risk of spreading, and any ulceration can move the disease into a later stage. Because of that risk, the doctor may recommend more aggressive treatment.

Learn more about sentinel lymph node biopsy and melanoma treatment options.

Advanced Melanomas

Spread beyond the primary tumor to other parts of the body. There are also subdivisions within these stages.

  • Stage III.  These tumors have spread to either the local lymph nodes or more than 2 cm away from the primary tumor through a lymph vessel but not yet to the local lymph nodes. Thickness no longer plays a staging role. If local lymph nodes are palpable, meaning they feel enlarged when examined by a doctor, the tumor has reached them and they are removed. Sometimes melanoma is present even in lymph nodes that are not palpable. Sentinel lymph node biopsy (SLNB) is a technique used to determine whether the disease has spread to one or more nearby lymph nodes. Melanomas that have spread to very small areas of nearby skin or underlying tissue but have not reached the lymph nodes are known as “satellite tumors” — and are also included in Stage III.The staging system includes metastases so tiny they can be seen only by microscope (micrometastases). The degree of disease advancement depends on whether the tumor has reached the nodes, the number of nodes involved, the number of cancer cells found in them and whether or not they are microscopic or are palpable and can be seen with the naked eye.
  • Stage IV. The cancer has advanced to distant body areas, lymph nodes or organs, most often the lungs, liver, brain, bone and gastrointestinal tract. The two main ways to determine the degree of advancement in Stage IV melanoma are the site of the distant tumors and the presence of elevated serum lactate dehydrogenase (LDH) levels. LDH is an enzyme that turns sugar into energy; the more found in blood or body fluids, the more damage has been done.

These stages are each further broken down, from lowest to highest risk, depending on different characteristics of the original tumor and the areas where it has spread.

Cancer staging can be complex and confusing. If you have been diagnosed, ask your doctor to explain your stage clearly, in a way that you can understand.

What happens after staging?

Once your melanoma stage is determined, your doctor will develop a treatment plan that’s best for you.

Find out more about melanoma treatment options.

Reviewed by:
Allan C. Halpern, MD
Ashfaq A. Marghoob, MD

Ofer Reiter, MD

Last reviewed: April 2019