Stages of melanoma skin cancer
Staging describes or classifies a cancer based on how much cancer there is in the body and where it is when first diagnosed. This is often called the extent of cancer. Information from tests is used to find out the size (thickness) of the tumour, which parts of the skin have cancer, whether the cancer has spread from where it first started and where the cancer has spread. Your healthcare team uses the stage to plan treatment and estimate the outcome (your prognosis).
The most common staging system for melanoma skin cancer is the TNM system. For melanoma skin cancer there are 5 stages – stage 0 followed by stages 1 to 4. Often the stages 1 to 4 are written as the Roman numerals I, II, III and IV. Generally, the higher the stage number, the more the cancer has spread. Talk to your doctor if you have questions about staging.
When describing the stage, doctors often use the words early stage, locoregional or metastatic.
Early stage means that the cancer is only in the skin where it started and has not spread to other parts of the body. It includes stage 0, stage 1A, stage 1B, stage 2A, stage 2B and stage 2C melanoma skin cancers.
Locoregional means the cancer has spread to nearby lymph nodes, or it has spread to nearby areas of skin or lymph vessels. It includes stage 3 melanoma skin cancer.
Metastatic means that the cancer is in a part of the body farther from where it started. It includes stage 4 melanoma skin cancer.
Find out more about staging cancer.
Stage 0 (or melanoma in situ)
The cancer cells are only in the top or outer layer of the skin (epidermis). Some doctors describe melanoma in situ as a precancerous condition of the skin.
The tumour is 0.8 mm thick or less with no ulceration of the tumour (there is no broken skin or open wound).
Or the tumour is more than 0.8 mm thick but not more than 1 mm thick. There may be ulceration of the tumour (broken skin with an open wound).
The tumour is more than 1 mm thick but not more than 2 mm thick. There is no ulceration of the tumour.
The tumour is more than 1 mm thick but not more than 2 mm thick. There is ulceration of the tumour.
Or the tumour is more than 2 mm thick but not more than 4 mm thick. There is no ulceration of the tumour.
The tumour is more than 2 mm thick but not more than 4 mm thick. There is ulceration of the tumour.
Or the tumour is more than 4 mm thick with no ulceration of the tumour.
The tumour is more than 4 mm thick with ulceration of the tumour.
The cancer has spread to 1 or more lymph nodes near where the cancer started (regional lymph nodes). After lymph nodes are removed and examined by a pathologist, the cancer can be assigned stage 3A, 3B, 3C or 3D. It depends on:
- the number of lymph nodes that contain cancer
- the amount of cancer in the lymph nodes
- if the cancer has spread to nearby areas of skin (satellite tumours) or lymph vessels (in transit tumours)
The cancer has spread to other parts of the body (called distant metastasis), such as to the lungs or liver. This is also called metastatic melanoma skin cancer.
Recurrent melanoma skin cancer
Recurrent melanoma skin cancer means that the cancer has come back after it has been treated. If it comes back in the same place or close to where the cancer first started, it’s called locally recurrent melanoma skin cancer. It can also recur in another part of the body farther from where it started. This is called metastatic melanoma skin cancer or a distant recurrence.
What’s the lifetime risk of getting cancer?
The latest Canadian Cancer Statistics report shows about half of Canadians are expected to be diagnosed with cancer in their lifetime.