Stage 3 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 a treatment for stage 3 melanoma. Some people may have other treatments instead of an operation. This may include chemotherapy, targeted cancer drugs or immunotherapy. Or they may have these treatments as well as surgery.
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 normally have some other tests and scans to help with this.
What is stage 3 melanoma skin cancer?
Stage 3 generally means that cancer cells have spread to either:
- an area between the melanoma and the nearby
lymph nodes 
- the lymph nodes close to where the melanoma started
Cancer cells found between the melanoma and the nearby lymph nodes are called:
- micro satellite metastases – tiny amounts of cancer cells found next to the melanoma. These can only be seen through a microscope
- satellite metastases – cancer cells found within 2cm of the melanoma
- in-transit metastases – cancer cells that have spread more than 2cm away from the melanoma but not as far as the nearest lymph node
Sometimes doctors find melanoma cells in the lymph nodes or nearby but can’t find the original (primary) melanoma.
Stage 3 melanoma can be divided into A, B, C and D depending on if there are:
- micro satellite, satellite or in-transit metastases
- cancer cells in one or more lymph nodes
Your doctor or specialist nurse can tell you what your exact stage of melanoma is and what it means.
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 3 is:
- Any T, N1 to N3, M0
What are the lymph nodes?
The lymph nodes are part of the lymphatic system. This is a network of thin tubes (vessels) and small pieces of tissue (nodes) that carry a fluid called lymph around the body. The lymphatic system is an important part of the . It plays a role in fighting infection and destroying old or abnormal cells.
Lymph nodes are bean shaped. They filter the lymph fluid and trap bacteria, viruses and cancer cells.
Tests on your lymph nodes
Your doctor will usually recommend a test to see if there are cancer cells in the lymph nodes near the melanoma.
You normally have a test called a sentinel lymph node biopsy (SLNB). Your doctor removes the first lymph node or nodes that the melanoma could have spread to.
You have a SLNB at the same time as a .
Swollen lymph nodes
If your doctor can feel that your lymph nodes near the melanoma are swollen (enlarged), you usually have an ultrasound scan instead of an SLNB. They may take a sample of tissue (biopsy) from the lymph node to check for cancer cells.
Treatment for 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
Genetic tests on the melanoma
Your doctor will send a sample of the melanoma for genetic testing. This is to look for changes to a called the BRAF gene. These gene changes can make melanoma cells grow.
If you have changes in the BRAF gene, doctors describe the melanoma as BRAF positive. If you don’t have changes, then the melanoma is BRAF negative. This is also called BRAF wildtype. Knowing this helps your doctor decide whether you should have immunotherapy or targeted cancer drugs.
Micro satellite, satellite or in-transit metastases
Your doctor will normally remove the melanoma in an operation called a wide local excision. They may also be able to remove some micro satellite, satellite or in-transit metastases.
If you can’t have surgery, or you have had metastases treated before and they’ve come back, you might have one of the following:
- an injection of treatment directly into the melanoma (intralesional therapy), for example talimogene laherparepvec (T-VEC)
chemotherapy combined with an electric current (electrochemotherapy)- chemotherapy directly into the leg or arm where the melanoma is - isolated limb infusion or isolated limb perfusion
targeted cancer drugs immunotherapy - chemotherapy into your bloodstream (intravenously)
radiotherapy - imiquimod cream
Melanoma in the lymph nodes
If your lymph nodes feel normal, but an SLNB shows a small number of melanoma cells have spread there, you might have:
- treatment with targeted cancer drugs or immunotherapy
- regular scans to check your lymph nodes
You don’t usually have surgery to remove the rest of the lymph nodes in this situation. Your doctor will talk to you about this.
If your lymph nodes are swollen
You usually have surgery to remove the lymph nodes in the area. You may also have the lymph nodes removed if they look abnormal and a biopsy shows they have cancer cells in them.
This operation is called a completion lymph node dissection.
Treatment after a completion lymph node dissection
After surgery to remove the lymph nodes your doctor might offer you targeted or immunotherapy drugs. The aim is to reduce the chance of the cancer coming back. This is called adjuvant treatment.
You might have targeted cancer drugs or immunotherapy for a year.
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.
