Melanoma stages in detail

As explained in What are the stages of melanoma, the stage of the cancer is given a number. This describes:

• The thickness of the tumour in mm: How far has it spread into the deeper layers of the skin?
• Ulceration: Has the cancer has broken the surface of the skin?
• Lymph nodes: Has it spread to nearby lymph nodes?
• Metastasis: Has it spread to other parts of your body?

To give the doctors more information about the stage of the melanoma, a more detailed staging may be done - adding the letters A-C to the numbers.

• Stage 1A: The melanoma is less than 0.8mm thick. The covering layer of skin over the tumour is not broken — it is not ulcerated.
• Stage 1B: The melanoma is less than 0.8mm thick and the skin is broken (ulcerated). Or it is between 0.8 and 1mm thick, and may be either ulcerated or not ulcerated.
• Stage 2A: The melanoma is between 1 and 2 mm thick and is ulcerated. Or it is between 2 and 4mm and is not ulcerated.
• Stage 2B: The melanoma is between 2 and 4mm thick and is ulcerated. Or it is thicker than 4mm and is not ulcerated.
• Stage 2C: The melanoma is thicker than 4mm and is ulcerated.
• Stage 3A: The melanoma has spread to 1 to 3 lymph nodes near the original tumour. The nodes are not enlarged and the melanoma can only be seen with a microscope. The melanoma can be of any thickness, but it is not ulcerated.
• Stage 3B: The melanoma can be of any thickness and is ulcerated. It has spread to 1 to 3 lymph nodes near the original tumour. The nodes can be enlarged or not enlarged. OR the melanoma can be of any thickness, but it is not ulcerated. The melanoma has spread to skin or lymph vessels around the original tumour. Nearby lymph nodes do not have melanoma cells.

Stage 3C describes one of the following:

• The melanoma has spread to 1 to 3 lymph nodes near the original tumour. The nodes are enlarged. The melanoma can be of any thickness and is ulcerated.
• The melanoma has spread to skin or lymph vessels near the original tumour. The lymph nodes do not contain melanoma. The melanoma can be of any thickness and is ulcerated.
• The melanoma has spread to 4 or more nearby lymph nodes, or to nearby lymph nodes that are clumped together. The melanoma can be of any thickness and may or may not be ulcerated.
• The melanoma has spread to skin or lymph vessels around the original tumour and to nearby lymph nodes. The nodes are enlarged because of the melanoma.

• Stage 4: The melanoma has spread to other areas of the body, such as the lung, liver or brain.