If the test results show you have melanoma, your doctor will work out the stage of the cancer. The stage describes how far the cancer has spread.
Staging the melanoma helps your health care team decide what treatment is best for you.
The expected outcome of your disease is called the prognosis, but it is only a prediction and some people do not find it helpful or even prefer not to know.
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Staging the melanoma
The test results will help your doctors assign a stage to describe the melanoma. You may also undergo some other diagnostic tests, including blood tests and imaging tests (ultrasound, CT scan or PET scan), to assess whether the melanoma has spread from the original site to other parts of the body.
- Stage 0 — The melanoma is confined to the outer layer of the skin (also known as in situ melanoma).
- Stage 1 — The melanoma has not moved beyond the primary site and is 2 mm or less in thickness (may or may not have ulceration).
- Stage 2 — The melanoma has not moved beyond the primary site and is 2 mm or greater in thickness (may or may not have ulceration).
- Stage 3 — The melanoma has spread to lymph nodes near the primary site, to nearby skin or to tissues under the skin (subcutaneous).
- Stage 4 — The melanoma has spread to distant lymph nodes and/or other parts of the body such as the lungs, liver, brain or bone.
Gene mutation testing
Approximately 40% of people with melanoma have a mutation in the BRAF gene and approximately 15% have a mutation in the NRAS gene. These mutations can cause cancer cells to multiply and contribute to the growth of melanomas.
If the melanoma is advanced (metastatic), mutation testing of tissue samples is recommended to identify particular genetic mutations that may respond to some medicines. See Targeted therapy for more details.
Prognosis means the predicted outcome of a disease. You may wish to discuss your prognosis and treatment options with your doctor, but it is not possible for any doctor to predict the exact course of the disease. Instead, your doctor can give you an idea about common issues that affect people with melanoma.
Melanoma can be treated most effectively in its early stages when it is still confined to the top layer of the skin (epidermis). The deeper a melanoma penetrates into the lower layers of the skin (dermis), the greater the risk that it could spread to nearby lymph nodes or other organs.
In recent years, clinical breakthroughs have led to new treatments that continue to improve the prognosis for people with advanced melanoma.