Risk groups for non-melanoma skin cancer

Doctors classify most non-melanoma skin cancers into risk groups that are based on several prognostic factors, including the size of the cancer and where it’s located.

The risk groups allow the doctor to estimate the chance that the cancer will come back (recur). Doctors also use the risk groups to help plan the best treatment.

The prognosis is usually very good for BCC because it can be found and treated early. BCC is classified as low or high risk based on its risk of coming back. If the BCC has any high-risk factor, it is automatically classified as high-risk BCC.

BCC is put in the low-risk group when any of the following are true:

• It is smaller than 2 cm and on the central part of the body (called the trunk), upper arms or legs.
• It is smaller than 1 cm on the cheeks, forehead, scalp or neck.
• It is nodular or superficial.
• It is a primary cancer that has not come back after treatment.
• The edge of the cancerous area is clear and smooth.
• The immune system is not weakened.
• There was no previous radiation therapy to the area.
• There is no cancer in or around nerves.

BCC is put in the high-risk group when any of the following are true:

• It is larger than 2 cm and on the trunk of the body, arms or upper legs.
• It is larger than 1 cm on the cheeks, forehead, scalp or neck.
• It is any size and on the eyelids, eyebrows, temples, nose, lips, ears, genitals, hands or feet.
• It is an aggressive (fast-growing and fast-spreading) subtype, such as infiltrative, morpheaform or micronodular.
• It has come back after treatment.
• The edge of the cancerous area is uneven.
• The immune system is weakened.
• There was previous radiation therapy to the area.
• The cancer has grown into or around nerves.

SCC is classified as low or high risk based on its risk of coming back. If the SCC has any high-risk factor, it’s automatically classified as high-risk SCC.

SCC is put in the low-risk group when any of the following are true:

• It is smaller than 2 cm and on the central part of the body (called the trunk), upper arms or legs.
• It is smaller than 1 cm on the cheeks, forehead, scalp or neck.
• It is less than 2 mm deep.
• The edge of the cancerous area is clear and smooth.
• It is low grade.
• It is growing slowly.
• It is caused by ultraviolet radiation.
• It is a primary cancer that has not come back after treatment.
• The immune system is not weakened.
• There was no previous radiation therapy to the area.
• There is no cancer in or around nerves.

SCC is put in the high-risk group when any of the following are true:

• It is larger than 2 cm and is on the trunk of the body, arms or upper legs.
• It is larger than 1 cm and is on the cheeks, forehead, scalp, nails or ankles.
• It is any size and on the head, neck, eyelids, eyebrows, temples, nose, lips, ears, genitals, hands, feet or skin around the eyes.
• It is 2 mm or more deep.
• It is high grade.
• It is growing quickly.
• The edge of the cancerous area is uneven.
• It is a high-risk subtype, such as desmoplastic SCC or adenosquamous carcinoma of the skin.
• It has come back after treatment.
• The immune system is weakened.
• There was previous radiation therapy to the area.
• It started from a chronic wound or scar.
• The cancer has grown into or around nerves, the lymphatic system or blood system.