Stage 1

The stage of a cancer tells you how big it is and how far it has spread. It helps your doctor decide which treatment you need.

Stage 1 is part of the number staging system and means your melanoma is at an early stage. It is only in the skin and there is no sign that it has spread to lymph nodes or other parts of the body.

Stage 1 can be divided into 1A and 1B.

Stage 1A

Stage 1A means the:

  • melanoma is less than 1 mm thick
  • outer layer of skin (epidermis) covering the tumour may or may not look broken under the microscope (ulcerated or not ulcerated)

Stage 1B

Stage 1B means the melanoma is between 1 and 2 mm thick and is not ulcerated.

Call Cancer Research UK’s information nurses on freephone 0808 800 4040 from 9am to 5pm, Monday to Friday, for more information about staging for melanoma.

TNM stages

Doctors also use another staging system for melanoma called the TNM staging system. It stands for Tumour, Node, Metastasis.

  • T describes the size of the tumour
  • N describes whether there are any cancer cells in the lymph nodes
  • M describes whether the cancer has spread to a different part of the body


The stage of your cancer helps your doctor to decide what treatment you need. Treatment also depends on:

  • where the melanoma is
  • your general health and level of fitness

Surgery is the main treatment. To diagnose melanoma doctors remove the abnormal area and a small area of surrounding skin.

You usually then have a second operation to remove a larger area of healthy tissue around where the melanoma was. This is called a wide local excision. 

For stage 1A melanoma, if your doctors are sure that they removed enough tissue, this is usually all the treatment you need.

For stage 1B and some stage 1A melanomas, your doctor might offer you a test to see if the cancer has spread to the nearby lymph nodes. The test is called a sentinel lymph node biopsy. Your doctor removes the first lymph node or nodes that the melanoma could have spread to and they are checked for cancer cells.

You have a sentinel lymph node biopsy while you're asleep (general anaesthetic) at the same time as a wide local excision.

For most people with thin melanomas, cancer cells aren’t found in the nearby lymph nodes. If they are (a positive sentinel lymph node biopsy) your stage of melanoma changes to stage 3.

Your doctor might suggest having regular ultrasound scans of the lymph nodes to check if the cancer grows (progresses). This is called surveillance.

They might suggest having treatment such as targeted cancer drugs or immunotherapy, to reduce the risk of the melanoma coming back. If a trial of new treatments is available, they may suggest you consider taking part in it.

Swollen lymph nodes

If after being diagnosed with melanoma your doctor can feel that the lymph nodes near to the melanoma are swollen (enlarged), you usually have an ultrasound scan and they take a sample of tissue from the lymph nodes (a biopsy).

Other number stages

Last reviewed: 
21 May 2020
Next review due: 
21 May 2023
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    American Joint Committee on Cancer
    Springer, 2017

  • Melanoma assessment and management
    National Institute for Health and Care Excellence, July 2015

  • BMJ Best Practice Melanoma
    BMJ Publishing Group, June 2018

  • Cutaneous melanoma: ESMO Clinical Practice Guidelines for diagnosis, treatment and follow-up
    R Drummer and others
    Annals of Oncology, 2015. Volume 26, Supplement 5, Pages v126 - v132

  • The Current Role of Sentinel Lymph Node Biopsy in the Management of Cutaneous Melanoma – a UK Consensus Statement based on a multi-disciplinary meeting held in Cambridge, UK on 17 May 2018
    Melanoma Focus, January 2019

  • Melanoma
    D Schadendorf and others
    The Lancet, 2018. Volume 392, Pages 971 – 984

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