Non-melanoma skin cancer is the most common cancer worldwide. Recent studies suggest that it is becoming much more common among women, and the increase is especially dramatic among young women. According to the Canadian Dermatology Association, a person born in 1930 faces a 1-in-500 chance of developing nonmelanoma skin cancer in his or her lifetime, whereas a person born after 1994 faces a 1-in-7 chance.

This increase has occurred because more people are overexposed to ultraviolet (UV) radiation. People are living longer. People of this generation have often been exposed to the sun more than their parents because they tend to have more opportunity for leisure activities in the sun. The thinning of the earth's ozone layer (caused by pollution and chemicals) also contributes to the increased occurrence of nonmelanoma skin cancer.

The two most common types of nonmelanoma skin cancer are basal cell carcinoma and squamous cell carcinoma. These account for 98 percent of nonmelanoma skin cancers. Men are slightly more likely than women to have basal cell carcinoma and two to three times more likely to have squamous cell carcinoma.

The risk of nonmelanoma skin cancer is higher for people who:

• have spent too much time in the sun without protection (the sun is the main source of UV radiation)

• use tanning lamps and tanning booths (also sources of UV radiation)

• have light-coloured eyes, hair and skin (especially skin that freckles or burns easily)

• have had sunburns as children or teenagers

• have a family history of skin cancer

• have been exposed to arsenic (a heavy metal used in making some insecticides) or other industrial chemicals (such as tar, coal and paraffin)

• have been exposed to therapeutic radiation

• have a history of non-cancerous skin growths

• have had chronic or severe skin inflammation or injury

• have a history of immune disorders