Stage 1 melanoma skin cancer
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.
Surgery is the main treatment for stage 1 melanoma skin cancer.
How does your doctor work out the stage?
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.
What is stage 1 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 
or other parts of the body.
Stage 1 can be divided into 1A and 1B.
Stage 1A
This means the melanoma is less than 0.8mm thick and is not ulcerated.
Stage 1B
This means the melanoma is one of the following:
-
less than 0.8mm thick and is ulcerated
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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
TNM stages
Doctors also use another staging system for melanoma called the TNM staging system. It stands for Tumour, Node, Metastasis.
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T describes the size of the tumour
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N describes whether there are any cancer cells in the lymph nodes
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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
Tests on your lymph nodes
Your doctor might do further tests to check for cancer cells in the lymph nodes near the melanoma.
Sentinel lymph node biopsy
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
lymph vessels 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 .
Swollen lymph nodes
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.
If there are cancer cells in your lymph nodes
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.
Treatment for stage 1 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
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.
Clinical trial
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.
