Staging of melanoma

The stage of a cancer describes its size and if it has spread. Knowing this helps doctors plan the best treatment.

Melanoma stages

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:

Stage 0 (melanoma in situ)

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

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

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 melanoma

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 melanoma

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.

Breslow thickness

The Breslow thickness describes how thick 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 (T) 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 1mm and 2mm thick
  • T3 – the melanoma is between 2mm and 4mm thick
  • T4 – the melanoma is more than 4mm thick.

TNM staging system for melanoma

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

T is for tumour

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

N is for nodes and nearby skin

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 is for metastasis

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.

About our information

  • References

    Below is a sample of the sources used in our melanoma information. If you would like more information about the sources we use, please contact us at cancerinformationteam@macmillan.org.uk

    Michielin O, van Akkooi ACJ, Ascierto PA, et al. Cutaneous melanoma: ESMO Clinical Practice Guidelines for diagnosis, treatment and follow-up. Annals of Oncology. 2019; 30, 12, 1884-1901 [accessed May 2022].

    Michielin O, van Akkooi ACJ, Ascierto PA, et al. ESMO consensus conference recommendations on the management of locoregional melanoma: under the auspices of the ESMO Guidelines Committee. Annals of Oncology. 2020; 31, 11, 1449-1461 [accessed May 2022].

    Peach H, Board R, Cook M, et al. Current role of sentinel lymph node biopsy in the management of cutaneous melanoma: A UK consensus statement. Journal of Plastic, Reconstructive & Aesthetic Surgery. 2020; 73, 1, 36-42 [accessed May 2022].


  • Reviewers

    This information has been written, revised and edited by Macmillan Cancer Support’s Cancer Information Development team. It has been reviewed by expert medical and health professionals and people living with cancer. It has been approved by Senior Medical Editor, Dr Samra Turajlic, Consultant Medical Oncologist.

    Our cancer information has been awarded the PIF TICK. Created by the Patient Information Forum, this quality mark shows we meet PIF’s 10 criteria for trustworthy health information.

The language we use

We want everyone affected by cancer to feel our information is written for them.

We want our information to be as clear as possible. To do this, we try to:

  • use plain English
  • explain medical words
  • use short sentences
  • use illustrations to explain text
  • structure the information clearly
  • make sure important points are clear.

We use gender-inclusive language and talk to our readers as ‘you’ so that everyone feels included. Where clinically necessary we use the terms ‘men’ and ‘women’ or ‘male’ and ‘female’. For example, we do so when talking about parts of the body or mentioning statistics or research about who is affected.

You can read more about how we produce our information here.

Date reviewed

Reviewed: 01 October 2022
|
Next review: 01 October 2025
Trusted Information Creator - Patient Information Forum
Trusted Information Creator - Patient Information Forum

Our cancer information meets the PIF TICK quality mark.

This means it is easy to use, up-to-date and based on the latest evidence. Learn more about how we produce our information.