Cancer and the Sun’s Ultraviolet Rays

The Canadian Dermatological Association states that the sun’s ultraviolet rays type A (UVA) and B (UVB) cause skin damage. 

UVA sunrays penetrate deep into the skin and cause wrinkling and premature aging of the skin.  They also cause some types of skin cancer.  Artificial tanning lights give off 5 times more UVA rays than natural sunlight and therefore should be avoided.

UVB sunrays are stronger than UVA sunrays and are primarily responsible for causing sunburns, premature aging of the skin and skin cancers. The sun also produces UVC rays.  They are considered very strong but do not reach the earth’s surface and therefore are unable to cause skin damage.

Each time our skin is exposed to the sun’s UVA and UVB rays, the skin cells are damaged.  Although some cells are capable of repairing themselves, others are not.  It is these damaged cells that eventually grow uncontrollably to produce a cancerous tumour on the skin.

There are three types of skin cancers:

Melanoma cancer– this type of skin cancer is the least common but the most serious and therefore any suspicious areas on the skin need to be immediately assessed by a physician.  It usually starts as a flat dark coloured spot with irregular edges that can increase in size and change it’s shape and colour as time passes.   Common areas on the body for melanomas to occur are the upper back or the back of the calf. 

Basal cell cancer – this type of skin cancer is the most common form of skin cancer.  Usually occurs in any sun-exposed areas of the body.  Basal cell cancer may appear as a growth, or bump located on the face, ear, neck, chest, back, or scalp.  It usually has a pearly or waxy appearance or can be white, light pink, brown or flesh coloured.  It can be flat or slightly raised and sometimes is described as a sore that will not heal.  Basal cell cancer requires treatment by a physician.

Squamous cell cancer – This type of cancer is the second most common skin cancer and like other skin cancers, it too usually occurs with severe sun damage.  Over time, the person develops a pre-malignant spot (sun spot) that can change into a squamous cell cancer.  Squamous cell skin cancers appear as thickened, red, scaly bumps or wart-like growths. They can also be described as a patch of crusted skin or as an open sore that does not heal. Squamous cell cancer, like other types of skin cancers, requires treatment by a physician.

To learn more about melanoma and recognize suspicious changes on the skin, go to the Canadian Dermatology Association’s website at www.dermatology.ca.

Sources:

Artificial Tanning. Retrieved May 17, 2005 from

 http://www.cancer.ca/ccs/internet/standard/0,3182,3172_273107_374382_langId-en,00.html.

Sun Facts. Retrieved May 17, 2005 from  http://dermatology.ca/english/sun/facts_e.html.