Skin cancer is an abnormal growth of cells that typically occurs on areas of the skin that are exposed to the sun. The three main types of skin cancer are basal cell carcinoma, squamous cell carcinoma and malignant melanoma. According to the Public Health Agency of Canada, the vast majority of skin cancer cases in the country are basal and squamous cell carcinomas, two forms of the disease that appear later in life, progress slowly and usually do not lead to death because they do not spread to other areas of the body. Malignant melanomas, which represent about five per cent of skin cancer cases, are more likely to be fatal. These cancers appear earlier in life, spread rapidly and can form on any area of the skin.
Symptoms of skin cancer
The symptoms of non-melanoma skin cancers differ by type but most involve changes in the skin’s appearance. According to the Canadian Cancer Society, you should see your doctor if you notice some of the following changes:
- Basal cell carcinoma – Typically develops on areas of the skin exposed to the sun, particularly the head, neck and face. Symptoms include: sores that don’t heal; pale white or flat yellow areas that look like scars; raised and scaly red patches; smooth and shiny lumps that are white, pink or red; sores that bleed; and growths that are itchy.
- Squamous cell carcinoma – Typically develops on areas of the skin exposed to the sun but can also form around the genitals or anus. Symptoms include: sores that don’t heal; rough red patches with irregular edges; raised lumps with an indention in the centre; wart-like growths; sores that crust or bleed easily; and growths that are itchy.
Melanoma skin cancer often starts as an abnormal looking mole that can form anywhere on the skin. A change in the colour, size or shape of these moles is usually the first sign of melanoma. Changes can occur to the mole itself or appear as a new mole. Other symptoms include: areas of the skin that do not heal; moles that ooze or bleed; and painful lesions that itch or burn.
Diagnosing skin cancer
To diagnose skin cancer, a doctor will typically inquire about signs and symptoms and conduct a skin exam. Depending on the results, a patient may be referred to a dermatologist or other expert, who can perform a biopsy of suspicious areas of the skin to determine the presence and type of cancer.
Treating skin cancer
Treatment varies depending on the size, type, stage and location of the cancer. Some small cancers are completely removed during the biopsy process and require no further treatment. In other cases, addressing the issue can include:
- Surgery (cancerous tissue is completely excised)
- Freezing (some skin cancers can be destroyed by liquid nitrogen)
- Mohs surgery (a procedure used on difficult to treat cancers used in areas where it is necessary to preserve as much skin as possible)
- Radiation therapy (used when surgery cannot remove all the cancerous cells)
- Chemotherapy (anti-cancer creams are applied to the surface of the skin)
- Immunotherapy (used in some cases of early stage melanoma)
Preventing skin cancer
About 90 per cent of skin cancers are the result of exposure to UV light, according to the Canadian Skin Cancer Federation, but other risk factors include:
- Complexion (fair-skinned people possess less melanin, which protects against damaging UV rays)
- Moles (people with 50 or more moles are at increased risk)
- Tanning beds (people who use a tanning bed for the first time before the age of 35 increase their risk of malignant melanoma by 75 per cent, according to the World Health Organization)
- Family history (having a relative with skin cancer raises the risk of diagnosis)
- Sunburn history (having one or more blistering sunburns in adolescence or adulthood can increase the risk of melanoma)
- Skin cancer history (people who have already had skin cancer face an elevated risk of another diagnosis)
Most forms of skin cancer are preventable and risk can be reduced by: Covering up when the UV index is 3 or higher, limiting exposure to the sun between 11 a.m. and 3 p.m., using sunscreen and avoiding tanning equipment.
Prevalence of skin cancer
Skin cancer is the most common form of cancer in Canada, accounting for around one-third of all new diagnoses, with rates continuing to rise. Specific statistics for non-melanoma cancers (such as basal cell and squamous) are not reported because they are usually identified and successfully removed in doctors’ offices. Melanoma cancer, the less common but more serious form of skin cancer, was diagnosed in around 7,800 Canadians in 2019 with around 1,300 dying from the disease. Roughly one in 42 men and one in 56 women will develop melanoma during their lifetimes, with one in 219 men and one in 402 women expected to die from the disease.
Support for skin cancer
There is a wealth of resources online to help if you or someone you know has been diagnosed with skin cancer. The Save Your Skin Foundation is a patient-led, not-for-profit group that provides support to Canadians living with skin cancer. The Melanoma Network of Canada provides the latest news and developments in the fight against skin cancer and connect with professionals and survivors of the disease.