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Stages and grades

Read about the staging and grades of non melanoma skin cancer.

Stage of cancer

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

Your doctor might carry out a number of tests to stage your cancer. Most basal cell cancers (BCC) don't need staging because it's very rare for them to spread. They will only be staged if they're very large. Staging is more likely for squamous cell skin cancers (SCC) because they can spread, although this is still rare.

Doctors can use a numbers system or sometimes the TNM system (Tumour, Node, Metastases) to stage your cancer. 

Stage 0

Stage 0 is also called Bowen's disease or carcinoma in situ. Carcinoma means there are cancer cells. In situ means the cells are still in the place where they started to develop. So the cells have started to turn into cancer, but they have not yet spread or grown into surrounding areas of the skin. 

Bowen's disease might develop into SCC if it's not treated. So your doctor may describe this stage as pre cancerous or pre malignant.

Stage 1

Stage 1 means the cancer is 2cm across or less and has 1 or no high risk features. High risk features mean the cancer:

  • is more than 2mm thick
  • has grown in the lower dermis
  • has grown into the space around a nerve (perineural invasion)
  • started on the ear or lip
  • looks very abnormal under the microscope (the cells are poorly differentiated or undifferentiated)

Stage 2

Stage 2 means the cancer is more than 2cm across, or has 2 or more high risk features.

Stage 3

Stage 3 means the cancer has either:

  • grown into the bones in the face, such as the jaw bone or the bone around the eye
  • spread to a nearby lymph node (or lymph gland) on the same side of the body (and is less than 3cm)

Stage 4

Stage 4 cancer means the cancer has either:

  • grown into the spine, ribs or lower part of the skull
  • spread to a lymph node that's more than 3cm, or to an internal organ such as the lungs


The grade of a cancer tells you how much the cancer cells look like normal cells.

The grade gives your doctor an idea of how the cancer might behave and what treatment you need.

The grades of cancer cells are from 1 to 3:

  • grade 1 (low grade) look most like normal cells
  • grade 2 look a bit like normal cells
  • grade 3 (high grade) look very abnormal and not like normal cells
Last reviewed: 
26 Jul 2017
  • TNM Classification of Malignant Tumours (7th edition)
    International Union Against Cancer   
    L.H. Sobin, M.K. Gospodarowicz, Ch. Wittekind
    John Wiley & Sons, Hoboken, New Jersey, 2009

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