Stages and types of melanoma
The number stage of a melanoma tells you how thick it is and if it has spread. It also tells you whether the top layer of the melanoma looks broken (ulcerated) when looked at under a microscope. Knowing this helps your doctor decide which treatment you need.
Doctors also use another staging system for melanoma called the TNM staging system. It stands for Tumour, Node, Metastasis.
T describes the size of the tumour
N describes whether there are any cancer cells in the lymph nodes
M describes whether the cancer has spread to a different part of the body
The TNM staging system describes the cancer in detail. The number staging system puts these details together to give an overall stage. This can be easier to understand.
In the TNM staging system, stage 1 can be:
T1a, N0, M0
T1b, N0, M0
T2a, N0, M0
Find out more about TNM staging for melanoma skin cancer
To diagnose melanoma your doctor removes the abnormal area and a small area of surrounding skin. This is called an excision biopsy. A specialist doctor (pathologist) looks at the biopsy under a microscope. If there are melanoma cells, they will work out the stage of the cancer.
You may have some other tests and scans to help with this.
Read more about the tests for melanoma skin cancer
Stage 1 means the melanoma is at an early stage. It is only in the skin and there is no sign that it has spread to nearby or other parts of the body. Stage 1 can be divided into 1A and 1B.
This means the melanoma is less than 0.8mm thick and is not ulcerated.
This means the melanoma is one of the following:
less than 0.8mm thick and is ulcerated
between 0.8 and 1mm thick and it may or may not be ulcerated
more than 1mm thick up to 2mm and is not ulcerated
Your doctor might do further tests to check for cancer cells in the lymph nodes near the melanoma.
If you have stage 1B melanoma, your doctor may offer you a test called a sentinel lymph node biopsy (SLNB). They may also offer you the test if you have stage 1A melanoma and either:
there are cancer cells in the blood vessels or of the melanoma
the cancer cells are dividing quickly
During the test, your doctor removes the first lymph node or nodes that the melanoma could have spread to. You usually have this test at the same time as a .
Read more about having a sentinel lymph node biopsy
If your doctor can feel that the lymph nodes near the melanoma are swollen (enlarged), you usually have an ultrasound scan instead of a SLNB. They may take a sample of tissue (biopsy) from the lymph node to check for cancer cells.
Read more about having an ultrasound and biopsy
Most people with thin melanomas don’t have cancer cells in the nearby lymph nodes.
If your doctor finds cancer cells in the lymph nodes near the melanoma, the stage changes to stage 3.
Read more about stage 3 melanoma skin cancer
The stage of the cancer helps your doctor decide what treatment you need. Treatment also depends on:
where the melanoma is
your general health and level of fitness
Surgery is the main treatment for stage 1 melanoma.
You usually have an operation to remove a larger area of skin around where the melanoma was. This is called a wide local excision. Doctors do this to remove any melanoma cells that might be in the surrounding skin.
Read more about having a wide local excision
Your doctor might ask if you’d like to take part in a clinical trial. Doctors and researchers do trials to make existing treatments better and develop new treatments.
Find out more about clinical trials
Last reviewed: 02 Jan 2025
Next review due: 02 Jan 2028
If you have symptoms of melanoma skin cancer you should see your GP. They might ask you to have some tests and may refer you to a specialist.
The stage of a melanoma skin cancer tells you how deeply it has grown down into the skin. It also tells you if it has spread elsewhere in your body and how far.
Treatments include surgery, cancer drugs and sometimes radiotherapy. Which ones you have depends on the melanoma stage, where on your body it is and your general health.
Coping with melanoma skin cancer can be difficult. You might find it helpful to talk about your feelings. And there are people who can support you and your family.
Survival for melanoma skin cancer depends on many factors including the stage of the cancer when it was diagnosed, the treatment you have and your general health.
Melanoma develops in cells called melanocytes. You have these in your skin and other parts of your body. Melanoma that starts in the skin is called melanoma skin cancer.
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