Risks for non-melanoma skin cancer

Some things can affect your risk, or chance, of developing cancer. Certain behaviours, substances or conditions can increase or decrease the risk. Most cancers are the result of many risks. But sometimes cancer develops in people who don't have any risks.

Sun and indoor tanning are the main risks for non-melanoma skin cancer.

Non-melanoma skin cancer is the most common cancer diagnosed in Canada. Basal cell carcinoma (BCC) and squamous cell carcinoma (SCC) are the 2 main types of non-melanoma skin cancer.

Most cancer registries in Canada don't collect information about non-melanoma skin cancers. This is because these cancers are hard to keep track of. The information often doesn’t get reported because non-melanoma skin cancer is usually diagnosed and treated easily in a doctor’s office.

The risk of developing non-melanoma skin cancer increases with age. Most new cases are diagnosed in people who are 70 or older. BCC seems to affect men and women equally, and SCC is diagnosed more often in men. We need more research and can't say at this time what the risk is for transgender, non-binary and gender-diverse people.

Some of the things that increase the risk for non-melanoma skin cancer may also cause actinic keratosis. Actinic keratosis is a precancerous condition of the skin. It's not cancer, but it can sometimes become SCC if it's not treated. Find out more about precancerous conditions of the skin.

If you have a genetic condition that increases your risk for non-melanoma skin cancer, you may need to visit your doctor more often. Talk to your doctor about your risk and if you need to have certain tests to check for non-melanoma skin cancer.

There are several things that could increase your risk for non-melanoma skin cancer. Some of these risks can't be changed. But in some cases, there are things you can do to lower your risk.

The following can increase your risk for non-melanoma skin cancer:

Sun and indoor tanning

Light-coloured skin, eyes and hair

Personal history of skin cancer

Family history of non-melanoma skin cancer

Ionizing radiation

Arsenic

Contact with chemicals at work

PUVA therapy

Xeroderma pigmentosum

Basal cell nevus syndrome

Weak immune system

Sun and indoor tanning equipment, such as tanning beds and sun lamps, increase your risk for non-melanoma skin cancer. They are the main risks for non-melanoma skin cancer.

Having a tan means that your skin has been damaged. Sun and indoor tanning can cause sunburns, premature aging, cataracts and skin cancers.

Most cases of non-melanoma skin cancer are caused by exposure to ultraviolet radiation (UVR) from the sun over a long time. People who work outside, such as farmers, have a higher risk of developing non-melanoma skin cancer because they are outdoors for long periods of time. People who live at high altitudes or in areas with year-round, bright sunlight also have a greater risk of developing non-melanoma skin cancer.

BCC has been most strongly linked to on-and-off exposure to UVR, sunburns and overexposure during the childhood or teenage years.

SCC is most strongly linked to total lifetime sun exposure. This includes recreational and work-related exposure and being exposed to UVR a lot during childhood.

Learn more about how to be sun safe.

People with fair or light-coloured skin and many freckles have a higher risk of developing non-melanoma skin cancer than people with other skin types such as black or brown skin. People with blonde or red hair and blue, green or grey eyes also have a higher risk of developing non-melanoma skin cancer. The risk is greater because people with these features have less melanin. Melanin is what gives colour to your skin, hair and eyes. It's believed that melanin also helps protect the skin from UVR. People with fair or light-coloured skin who have had very bad sunburns at an early age have the highest risk for non-melanoma skin cancer

Albinism is a condition that causes a lack of melanin in the skin, eyes and hair. People with this condition burn easily, increasing their risk of developing non-melanoma skin cancer.

If you've already had skin cancer (non-melanoma or melanoma), you have a greater risk of developing another skin cancer, including BCC and SCC.

Having a family history of non-melanoma skin cancer increases your risk of developing non-melanoma skin cancer. The risk is greater for SCC.

People who've hadradiation therapy (a source of ionizing radiation) have a greater risk of developing non-melanoma skin cancer in the treatment area. This type of skin cancer can develop 15 to 20 years after they've received radiation therapy.

Radiation exposure from nuclear fallout, such as in Hiroshima, Japan, is linked with a higher risk of developing non-melanoma skin cancer.

Coming into contact with arsenic increases the risk for non-melanoma skin cancer. Arsenic is a natural substance found in rocks and soil. Arsenic and substances that contain arsenic are also found in certain types of wood preservatives, pesticides and insecticides.

People who work in mining and smelting industries can be exposed to arsenic. People who manufacture and apply pesticides and insecticides may also be exposed to arsenic.

The biggest risk of exposure is through drinking water that contains high levels of arsenic. Arsenic can get into drinking water from natural sources or from certain types of mining, smelting or manufacturing plants.

Learn more about arsenic and how to reduce your risk.

Coming into contact with the following chemicals at work increases the risk for non-melanoma skin cancer:

• coal and shale
• industrial tar and pitch
• creosote
• chimney soot
• paraffin

Learn more about how to be safe at work.

PUVA therapy is a treatment used for skin conditions such as psoriasis. It uses the drug psoralen and ultraviolet A (UVA) radiation. Psoralen makes the skin more sensitive to UVA light.

Receiving PUVA therapy for a long time increases your risk of developing SCC.

Xeroderma pigmentosum (XP) is an inherited condition that affects the skin so it can't repair damage caused by ultraviolet radiation from the sun. XP increases the risk of developing non-melanoma and melanoma skin cancers.

Basal cell nevus syndrome is a genetic condition that causes different problems with the skin, eyes, nervous system, endocrine glands and jawbone. Basal cell nevus syndrome increases the risk of developing BCC and a type of brain tumour called a medulloblastoma.

Basal cell nevus syndrome is also called Gorlin syndrome or nevoid basal cell carcinoma syndrome.

Having a weak immune system (immunosuppression) increases your risk for non-melanoma skin cancer. You may have a weak immune system for different reasons, including if you have HIV (the virus that causes AIDS) or if you have had an organ transplant and must take medicines to suppress your immune system.

The following have been linked with an increased risk of non-melanoma skin cancer or BCC only. More research is needed to know for sure that they are risks:

• human papillomavirus (HPV) infection
• taking medicines that make your skin more sensitive to the sun (called photosensitizing drugs)
• tall adult height (BCC)
• alcohol (BCC)

Drinking coffee has been linked with a decreased risk of BCC, but more research is needed to know for sure that it lowers the risk.

To make the decisions that are right for you, ask your doctor questions about risks. Learn how cancer can be prevented and what you can do to reduce your risk.