Staging of melanoma

The stage of the melanoma describes:

• how thick (deep) it is
• whether it has spread from where it started.

Knowing the stage of the melanoma helps doctors plan the best treatment for you.

The way melanoma is staged is complicated. This section gives a simple explanation of 3 different ways of staging melanoma:

• the number stages from 0 to 4
• Breslow thickness
• TNM staging.

Your specialists can give you more information about the stage of your 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 for free on 0808 808 00 00.
• Chat to our specialists online.

Melanoma in situ is a term used to describe the earliest stage of melanoma. The melanoma is only in the top layer of skin, called the epidermis. It has not started to spread into the dermis. People with melanoma in situ do not usually have any risk of the melanoma spreading to other parts of the body.

Stage 1 melanoma means the melanoma is either:

• 1mm or less thick
• 1 to 2mm thick and the skin over the melanoma has not broken.

This is an early-stage melanoma. It is only in the skin. It has not spread to other parts of the body.

Stage 2 melanoma means the melanoma is either:

• 1 to 2mm thick and the melanoma has broken the outer layer of skin (ulcerated melanoma)
• thicker than 2mm.

It has not spread to other parts of the body.

Stage 3 means the melanoma has spread in the same area of the body. It may have spread to the following areas:

• Nearby lymph nodes.
• Areas of skin less than 2cm away from where the melanoma started. These areas are called satellite metastases.
• Areas of skin more than 2cm away from where the melanoma started and up to the nearby lymph nodes. These areas are called in-transit metastases.

It has not spread to any other parts of the body.

Stage 4 means the melanoma has spread to other areas of the body such as:

• other areas of the skin
• the lungs, liver, bones or brain.

This is also called advanced or metastatic melanoma.

The TNM staging system describes the stage of melanoma using letters and numbers.

T stands for tumour. It describes the thickness of the melanoma. This is also called the Breslow thickness.

N stands for nodes and nearby skin. It describes if the melanoma has spread to nearby lymph nodes. It also describes any spread to areas of skin between the tumour and these lymph nodes. This is called in-transit, satellite or microsatellite metastases.

• N0 – The melanoma has not spread from where it started.
• N1 – The melanoma has spread to 1 lymph node or to nearby areas of skin.
• N2 – The melanoma has spread to 2 or 3 lymph nodes or to 1 lymph node and nearby skin.
• N3 – The melanoma has spread to 4 or more lymph nodes or to 2 or more lymph nodes and nearby skin or to any number of lymph nodes and these have stuck together.

M stands for metastases. It describes whether the melanoma has spread to other parts of the body such as the lungs, liver, bones, brain or distant areas of the skin. This is also called advanced or metastatic cancer.

• M0 – The melanoma has not spread to other parts of the body.
• M1 – The melanoma has spread to other parts of the body.