Staging of melanoma

The stage of the melanoma describes its size and how far it has spread. Knowing the stage of the melanoma helps doctors decide on the best treatment for you.

Your specialists can give you more information about the stage of your melanoma.

The way cancers are staged is complicated. This section gives a simple explanation of the different stages. We also have more detailed information about the TNM staging of melanoma.

We understand that waiting to know the stage of your melanoma can be a worrying time. We're here if you need someone to talk to. You can:

Call the Macmillan Support Line on 0808 808 00 00.
Chat to our specialists online.

Melanoma in situ (stage 0)

Melanoma in situ is a term used to describe the earliest stage of melanoma. This means the melanoma is only in the top layer of skin (epidermis) and has not started to spread down into the dermis. Because of this, people with melanoma in situ do not usually have any risk of the melanoma spreading to other parts of the body.

Stages 1 and 2

The melanoma is only in the skin (epidermis and dermis). It has not spread to other parts of the body.

Stage 3

The melanoma has spread to the lymph nodes closest to it, but not to any other parts of the body.

Stage 4

The melanoma has spread to distant areas of skin. Or to other organs such as the lungs, liver or brain. This is called advanced or metastatic melanoma.

Breslow thickness

Doctors also use a measurement called Breslow thickness to describe how thick (deep) the melanoma is. It measures in millimetres (mm) how far the melanoma cells have grown down into the layers of skin.

There are 5 levels of tumour thickness:

Tis – the melanoma cells are only in the very top layer of the skin (epidermis).
T1 – the melanoma is 1mm thick or less.
T2 – the melanoma is between 1.1mm and 2mm thick.
T3 – the melanoma is between 2.1mm and 4mm thick.
T4 – the melanoma is more than 4mm thick.

The different levels of tumour thickness

TNM staging system for melanoma

The TNM staging system gives more details about the melanoma.

T stands for tumour. It describes:

the thickness (depth) of the melanoma – which is called the Breslow thickness
whether the melanoma is ulcerated – this means the layer of skin covering the melanoma is broken.

N stands for lymph nodes. It shows how many lymph nodes the melanoma has spread to.

M stands for metastases. It describes whether the melanoma has spread to other parts of the body (secondary or metastatic cancer).

Detailed staging of melanoma

The TNM staging system groups melanomas into a number stage between 0 and 4.

Stage 0

The melanoma is only in the top layer of the skin (epidermis). It has not started to spread into deeper layers.

Stage 1

The melanoma is up to 2mm thick, with or without ulceration. It has not spread to the lymph nodes or other parts of the body.

Stage 2

The melanoma is at least 1.1m thick, or can be more than 4mm thick. It might be with or without ulceration. It has not spread to the lymph nodes or anywhere else in the body.

Stage 3

The melanoma is in lymph nodes close to the melanoma. It has not spread to anywhere else in the body. Stage 3 is divided into 4 stages.

Stage 3A

The melanoma is in up to 3 lymph nodes. It is up to 2mm thick, with or without ulceration. The melanoma cells in the lymph nodes can only be seen under a microscope.

Stage 3B

Stage 3B melanoma can mean one of the following:

There is no sign of melanoma on the skin and the melanoma is in 1 lymph node.
The melanoma has spread to the skin or lymphatic vessels near the melanoma but is not in the lymph nodes.

Or stage 3B can mean the melanoma is between 1.1 and 2mm thick, with ulceration.

Stage 3B can also mean the melanoma is between 2.1 and 4mm thick,without ulceration, and one of the following:

The melanoma is in 1 lymph node.
The melanoma has spread to the skin or lymphatic vessels near the melanoma but is not in the lymph nodes.
The melanoma is in 2 to 3 lymph nodes.

Stage 3C

Stage 3C melanoma can mean there is no sign of melanoma on the skin, and one of the following:

The melanoma is in 2 to 3 lymph nodes.
The melanoma is in 1 or more lymph nodes and has spread to the skin or lymphatic vessels near the melanoma.
The melanoma has spread to 3 or more lymph nodes that are clumped together.

Stage 3C can mean the melanoma is between 0.8mm and 4mm, with or without ulceration, and one of the following:

The melanoma is in 1 or more lymph nodes.
The melanoma has spread to the skin or lymphatic vessels near the melanoma.
The melanoma has spread to 3 or more lymph nodes that are clumped together.

Stage 3C can also mean the melanoma is between 2.1 and 4mm thick, with ulceration.

Or stage 3C could mean the melanoma is 4mm or thicker, without ulceration, and one of the following:

The melanoma is in up to 3 lymph nodes.
The melanoma has spread to the skin or lymphatic vessels near the melanoma, but is not in the lymph nodes.
The melanoma has spread to lymph nodes that are clumped together.

Stage 3C can sometimes mean the melanoma is 4mm or thicker, with ulceration, and one of the following:

The melanoma is in up to 3 lymph nodes.
The melanoma has spread to the skin or lymphatic vessels near the melanoma, but is not in the lymph nodes.
The melanoma has spread to 1 lymph node, and the skin or lymphatic vessels near the melanoma.

Stage 3D

The melanoma is thicker than 4mm, with ulceration, and one of the following:

The melanoma has spread to 3 or more lymph nodes that are clumped together.
The melanoma has spread to the skin or lymphatic vessels near the melanoma, and is in 1 or more lymph nodes.