Diagnosis & staging
Basal cell carcinoma (BCC) and squamous cell carcinoma (SCC) are different than the more serious
type of skin cancer called melanoma.
Another type of skin cancer is skin lymphoma.
Skin does many things. It keeps moisture inside your body. It is also part of your immune system.
- Epidermis: outer layer of the skin. New skin cells are made in the bottom layer, called the basal layer.
- Skin cancers start in this layer, usually on skin that has been exposed to the sun.
- Dermis: made up of connective tissue, blood vessels, and nerves.
- Contains hair follicles, sweat glands, sebaceous glands and nerve endings.
- Hypodermis: made of fat and connective tissue.
Image of skin layers
Cancers of the skin are also called cutaneous cancers or dermatological cancers. Melanoma may also be called cutaneous malignant melanoma.
- Any change in your skin, such as a sore that does not heal.
- A new skin spot or growth.
- A change in a skin spot or growth.
If you have any signs or symptoms that you are worried about, please talk to your family doctor or nurse practitioner.
Tests that may help diagnose non-melanoma skin cancer include:
- Physical exam by a family doctor or dermatologist (skin doctor), including exam of lymph nodes.
- Biopsy: a doctor removes a sample of skin. The tissue is then examined by a specialist doctor (pathologist) under a microscope.
There are two main types of non-melanoma skin cancer.
- Most common type of skin cancer.
- About 75-80% (75-80 out of 100) of all skin cancers.
- Often found in skin that has had severe sun damage. Most commonly found on your face, ears, scalp, back of hands, arms or legs.
- Usually grows slowly.
- Second most common type of skin cancer.
- About 20% (20 out of 100) of all skin cancers.
- Grows slowly, but more quickly than basal cell carcinoma.
- Often found in skin that has been exposed to the sun.
- Pre-cancerous (may develop into squamous cell carcinoma).
- Rough, scaly spots that develop on skin that has been most exposed to the sun.
Staging describes the cancer. Staging is based on how much cancer is in the body, where it was first diagnosed, if the cancer has spread and where it has spread to.
The stage of the cancer can help your health care team plan your treatment. It can also tell them how your cancer might respond to treatment and the chance that your cancer may come back (recur).
Doctors do not often use staging for non-melanoma skin cancer. This is because these cancers are often found early and are treated. They do not often spread to other parts of the body. Some doctors group these cancers into risk groups instead of staging.
Risk groups are based on several things, including the grade of the cancer. For more about the grade of non-melanoma skin cancer, see grading section below.
- On the trunk of the body, arms, legs, cheeks, forehead, temples, scalp, neck or chin.
- 2 cm or smaller.
- It is a primary cancer and not a cancer that has come back after treatment.
- Edge is clear and smooth.
- No cancer in or around nerves.
- On eyelids, nose, ears, or skin around the eyes.
- Larger than 2 cm.
- Aggressive type of cancer.
- Has come back after treatment.
- Edge is uneven.
- Has grown into or around nerves.
- Anywhere on the skin except for the ears, lips or scalp.
- Smaller than 2cm.
- Less than 2 mm deep.
- Only in the top or outer layer of the skin.
- Low grade.
- Primary cancer.
- No cancer in or around nerves.
- On the ears, lips or scalp.
- 2 cm or larger.
- 2 mm or more deep.
- High grade.
- Growing quickly.
- Has come back after treatment.
- Person has a weakened immune system.
- Cancer has grown into or around nerves
Below is staging for certain types of non-melanoma skin cancer:
- Stage 0 (carcinoma in situ): Cancer cells are only in the top layer of the skin (epidermis). Squamous cell carcinoma in situ is also called Bowen's disease.
- Stage 1: Tumour is 2 cm (about 1 inch) or smaller.
- Stage 2: Tumour is larger than 2 cm but not more than 4 cm (1.5 inches)
- Stage 3 is any of the following:
- Tumour is larger than 4 cm.
- Tumour has slightly worn away nearby bone (bone erosion).
- Tumour has grown into or around nerves (perineural invasion).
- Tumour has grown deep, past the fat under the skin (deep invasion.
- Cancer has spread to 1 lymph node. The lymph node is 3 cm (just over 1 inch) or smaller.
- Stage 4A is any of the following:
- Cancer has spread to 1 lymph node that is larger than 3 cm but not more than 6 cm (about 2 inches). The lymph node is on the same side of the body where the cancer started.
- Cancer has spread to many lymph nodes and none of the lymph nodes are larger than 6 cm. The lymph nodes are on the same side of the body where the cancer started.
- Cancer has spread to a lymph node that is larger than 6 cm.
- Stage 4B: Cancer has spread to other parts of the body (called distant metastasis), such as the liver or lymph nodes on the other side of the body from where the cancer started.
Staging is the same as non-melanoma skin cancer staging above, except:
- Stage 3 is any of the following:
- Tumour is larger than 4 cm.
- Tumour has slightly worn away nearby bone (bone erosion).
- Tumour has grown into or around nerves (perineural invasion).
- Tumour has grown deep, past the fat under the skin (deep invasion).
- Cancer has spread to 1 lymph node. The lymph node is 3 cm (just over 1 inch) or smaller. Lymph nodes is on the same side of the body as where the cancer started.
- Stage 4A is one of the following:
- Cancer has spread to 1 or more lymph nodes that are large than 3 cm. The lymph nodes may be one or both sides of your body.
- Tumour has grown into bone, such as your skull or ribs. Cancer may have spread to 1 or more lymph nodes.
For more information on staging, see our About Cancer page.
The grade of the cancer describes how different the cancer cells look from normal cells and how fast the cancer cells are growing. A pathologist will give the cancer a grade after looking at the cells under a microscope.
Non-melanoma skin cancer can be grade 1, 2, 3 or 4. The lower the number, the lower the grade.
Low grade: cells are abnormal but look a lot like normal cells. Low grade cancers usually grow slowly and are less likely to spread.
High grade: cells are abnormal and do not look like normal cells. High grade cancers usually grow more quickly and are more likely to spread.
The grade of the cancer can help your health care team plan your treatment.
