Basal cell carcinoma is the most common form of skin cancer, affecting 50 to 60,000 Canadians each year. In fact, it is the most common of all cancers. One out of every three new cancers is a skin cancer, and the vast majority are basal cell carcinomas (BCC). These cancers arise from trichoblasts, cells that resides in/close to the basal cell layer, or the lowest layer, of the epidermis (outer skin layer). Until recently, those most often affected were older people, particularly men who had worked outdoors. The number of new cases of BCC has increased sharply each year in the last few decades, with the average age of onset steadily decreasing. More women are getting BCCs than in the past; nonetheless, men still outnumber women.
The Major Cause
Chronic exposure to ultraviolet radiation (ie. sunlight), particularly UVB is the cause of almost all basal cell carcinomas, which occur most frequently on exposed parts of the body — the face, ears, neck, scalp, shoulders, and back. Rarely, however, tumours develop on non-exposed areas. In a few cases, contact with arsenic, genetic factors, exposure to radiation, and complications of burns, scars, vaccinations or even tattoos are contributing factors. Artificial sources of ultra violet light, including tanning beds, may also contribute to the cause of BCC.
Who Gets It
Anyone with a history of frequent sun exposure can develop BCC. While it commonly appears after the age 40, anyone with the above risk factors can develop BCC and it is being seen in younger and younger patients. Genetics also plays a role as people who have fair skin, blonde or red hair and blue, green, or gray eyes are at highest risk. The susceptibility for having multiple occurrences of BCC may be inherited. Those whose occupations require long hours outdoors or who spend extensive leisure time in the sun are in particular jeopardy.
Patients on long-term immunosuppressive drugs or those whose systems may be immunosuppressed due to illness are at higher risk for the development of BCC.
People who have a history of x-rays treatments for facial acne have increased risks.
Indoor tanning is also a known risk factor for development of all forms of skin cancer.
What to Look For
Although skin cancers can occur in non sun-exposed areas, the most common location for BCC is the face.
- A persistent, non-healing sore is a very common sign of an early basal cell carcinoma.
– An open sore that bleeds, oozes or crusts and remains open for three or more weeks.
– A reddish patch or irritated area, frequently occurring on the chest, shoulders, arms or legs.
– Sometimes the patch crusts.
– It may also itch or hurt.
– At other times, it persists with no noticeable discomfort.
- A shiny bump or nodule that is pearly or translucent and is often pink, red or white.
– Can also be tan, black, or brown, especially in dark-haired people, and can be confused with a mole.
- A pink growth with a slightly elevated rolled border and a crusted indentation in the center.
– As the growth slowly enlarges, tiny blood vessels may develop on the surface.
- A scar-like area that is white, yellow or waxy and often has poorly defined borders.
– The skin itself appears shiny and taut.
– This warning sign can indicate the presence of an aggressive tumour.
Frequently, two or more features are present in one tumour. In addition, basal cell carcinoma sometimes resembles non-cancerous skin conditions such as psoriasis or eczema. Only a trained physician, usually a specialist in diseases of the skin, can decide for sure. Learn the signs of basal cell carcinoma, and examine your skin regularly – once a month, or more often if you are at high risk. Be sure to include the scalp, backs of ears, neck, and other hard-to-see areas. (A full-length mirror and a hand-held mirror can be very useful). If you observe any of the warning signs or some other change in your skin, consult your physician immediately.
The Canadian Skin Cancer Foundation advises people to have a total-body skin exam by a dermatologist at regular intervals. The physician will suggest the correct time frame for follow-up visits, depending on your specific risk factors, such as skin type and history of sun exposure.
It is estimated that one per cent of all BCC cases will progress to advanced BCC and either invade the surrounding tissue (locally advanced) or spread to other parts of the body (metastasized), which may result in severe deformities, debilitating effects, and even death.
Advanced BCCs are often open lesions that may bleed, become infected, and may be associated with unpleasant odours, resulting in both stigmatization and social isolation. Multiple surgeries each year can take their toll on both the patient and their family.