Skin Cancer

UV radiation damages the DNA of skin cells. If this damage affects the DNA of genes that control cell growth, skin cancer may develop.

Skin cancer is the most common of all cancer types. It accounts for an estimated 1/3 of all new cases of cancer in Canada and its incidence rate continues to rise¹.

In 2008, approximately one in 425 Canadians is expected to develop some form of skin cancer, while 910 may die from melanoma². Fortunately, early detection can ensure effective treatmentand survival.

On this page:

• Types
• Detection
• Treatment
• Related Resources

Types

There are two main types of skin cancer: non-melanoma and malignant melanoma.

Most cases of skin cancer in Canada are non-melanomas, which develop from skin cells called basal cells and squamous cells. These skin cancers, or carcinomas, tend to develop later in life on skin that has been exposed repeatedly to the sun (such as the face, neck, or hands). Basal cell carcinomas (BCC) and squamous cell carcinomas (SCC) progress slowly and rarely cause death because they usually don't spread to other parts of the body. Nevertheless, they are important to recognize because they can cause scarring, disfigurement, or loss of function in certain parts of the body.

Melanomas account for only six percent of all skin cancers, but are the type most likely to be fatal. Unlike other skin cancers, they occur earlier in life on almost any part of the body and progress rapidly. Melanoma originates in melanocytes, the cells which produce brown pigment and color our skin. Melanoma is especially hard to stop once it has spread (metastasized) to other parts of the body. But it can be readily treated in its earliest stages. The main factors that predispose an individual to the development of melanoma seem to be recreational exposure to the sun and a history of sunburn. Based on current incidence rates, 1 in 90 Canadian women will develop melanoma during their lifetime³ whereas 1 in 74 Canadian men will develop the disease⁴.

Detection

Moles, spots and certain growths on the skin are usually harmless - but not always. That is why it is so important to examine the skin all over your body once a month and have a physician check you over once a year.

Early detection of skin cancer can ensure effective treatment. Using a bright light and mirrors, and working from top to bottom, examine:

• a. head and face (use a blow-dryer to inspect your scalp)
• b. hands and nails
• c. elbows, arms, and underarms
• d. neck, chest, and torso
• e. genitals and breasts
• f. back of neck, shoulders, upper arms, back, buttocks, and legs
• g. feet (including soles, heels, and nails)

Look for the following "ABCDE" warning signs:

• Asymmetry. Do the two halves not match if you imagine drawing a line through the mole?
• Borders. Are the edges uneven, scalloped or notched?
• Colors. Is there a variety of shades (brown, red, white, blue or black)?
• Diameter greater than 6mm. Is the mole the size of a pencil eraser or larger?
• Evolution. Has there been a change in size, shape, color, or height? Has a new symptom developed (such as bleeding, itching or crusting)?

If you detect any of these warning signs, see a physician promptly. It is particularly important for you to select a physician who specializes in skin cancer and is trained to recognize a melanoma at its earliest stage.

Treatment

If skin cancer is suspected, a biopsy must be taken and examined microscopically. If the diagnosis is confirmed, there are many treatment options from which to choose. The choice of treatment is based on the type, size, location, and depth of penetration of the tumor, as well as the patient's age and general state of health.

Related Resources

For information on what Health Canada is doing in this area, contact the Consumer and Clinical Radiation Protection Bureau.

For Health Canada publications related to skin cancer prevention, consult:

• Babies, Children and Sun Safety
• Preventing Skin Cancer
• Sunscreens
• Sun Safety (factsheet)
• Tanning Under Lights
• Ultraviolet Radiation From the Sun

For information on other agencies concerned about skin cancer:

•  Canadian Association of Provincial Cancer Agencies (CAPCA)
•  Canadian Cancer Society (CCS)
•  Canadian Dermatology Association
•  National Cancer Institute of Canada (NCIC)

For strategies or reports related to skin cancer, consult:

•  Canadian Strategy for Cancer Control
•  Progress Report on Cancer Control in Canada