THE DARK SIDE OF THE SUN: SKIN CANCER
Skin cancers are named for the cells in which they develop. They most often occur on the parts of the body most consistently exposed to the sun--the head (the face and tips of the ears), neck, arms and hands. Also, cancers are increasingly being found on the backs and chests of men and the lower legs on women.
Basal Cell Carcinoma is the most common form of skin cancer and the least life-threatening. Usually found on the head, neck or hand, it begins as a shiny, pearly nodule and can proceed to bleed and crust over repeatedly if left untreated, eventually destroying underlying tissues.
Squamous Cell Carcinoma is most often found on the lips, face or tips of the ears. It begins as red patches or nodules with well-defined outlines and may continue to grow (and spread to other parts of the body) if not treated.
Malignant Melanoma is the least common form of skin cancer but can spread throughout the body and eventually cause death if left untreated. It develops in or near a mole and is characterized by its black or brown color (with some red and blue portions) and irregular shape.
MALIGNANT MELANOMA IN ORANGE COUNTY
1984-’85 * 1985 ** 1984 % change Cases Male: 131 90 45.6 Cases per 14 9.7 --- 100,000 population Female: 112 85 31.8 Cases per 9.6 7.4 --- 100,000 population Total Cases 243 175 38.9 Total Cases per 11.5 8.5 --- 100,000 population Deaths Male: 28 31 -9.7 Deaths per 2.7 3.0 --- 100,000 population Female: 22 16 37.5 Deaths per 2.0 1.5 --- 100,000 population Total Deaths 50 47 6.4 Total Deaths per 2.4 2.2 ---
100,000 population * Latest available data
** The number of cases are preliminary and may actually be higher. Doctors were not required to track the number of skin cancer patients they treated until 1985.
SKIN TYPES
The risk of experiencing some kind of skin damage from overexposure to ultraviolet rays is directly related to skin type. That is, the fairer one’s skin, the more susceptible the person is to skin damage. And although incidences of skin cancer are also related to skin types, anyone can contract some form of the disease through prolonged exposure to sunlight.
Skin Type Sunburn and Tanning Susceptibility with Type Description I Always burns and never tans; fair skin with freckles, red or blond hair II Burns easily and tans minimally; generally fair-skinned III Burns moderately and tans gradually; average Caucasian type IV Burns minimally and always tans; generally has an olive complexion V Rarely burns and always tans; generally brown skinned VI Never burns but can tan darkly; generally black skin but can include others with very heavy pigmentation.
ULTRAVIOLET RAYS AND THEIR RESULTS
The tanning rays in the sun are ultraviolet-A (UVA) and ultraviolet-B (UVB).
UVA rays have longer wavelengths and are the most concentrated during the early morning or late afternoon hours. UVB rays have short wavelengths and are most heavily concentrated between 10 a.m. and 2 p.m. The chart below outlines the consequences of prolonged exposure to the different types of ultraviolet light during suntanning.
UVA UVB Skin Cancer Yes Yes Skin Burns Yes Yes Eye Burns** Yes Yes Photosensitivity*** photoallergic phototoxic Cataracts** Yes Yes Premature Skin Aging affects the deepest principally the layers epidermis Reduced Immunity* may damage can damage more Immunity* circulating immune superficial cells immune cells Blood Vessel deeper vessels more superficial Damage* vessels
** Prolonged, unprotected exposure to ultraviolet light can sometimes result in photokeratitis (a gritty sensation in the eyes) or conjunctivitis (pinkeye). It can also increase one’s risk of developing cataracts (a clouding of the lens of the eyes) later in life.
*** Photosensitizing agents, generally medicines and cosmetics, promote photoallergic (e.g. rash) or phototoxic (exaggerated sunburn) reactions.
* Both types of radiation have been shown to damage skin blood vessels. They have also been shown to have some effect on the body’s immune system, which in some cases could result in skin cancer.
SOME POINTS TO KEEP IN MIND TO PROTECT YOURSELF FROM THE SUN’S HARMFUL RAYS AND SKIN CANCER
Avoid the sun when its rays are strongest, generally between 10 a.m. and 2 p.m.
Beware of reflective surfaces. For instance, snow can reflect enough of the sun’s harmful rays to cause skin damage.
In high altitudes the atmosphere screens fewer of the sun’s harmful rays than at lower altitudes. Also, swimmers should remember that sun rays can penetrate 3 feet of water.
It is strongly recommended that all people use sunscreens or sun blocks, regardless of skin type. Sunscreens with a Sun Protective Factor (SPF) of 15 or more are considered most effective and should be applied at least one hour prior to exposure and again after swimming or if one perspires heavily. Also, a tinted opaque cosmetic foundation used along with the sunscreen can give women added protection from harmful rays.
Long-sleeved shirts, pants, bandannas for the neck and wide-brimmed hats are also recommended for anyone planning to spend any time in the sun.
Check your skin at least once a month for any abnormality that may signal skin cancer. Take special note of any moles, birthmarks or other blemishes. Any changes in size, shape or color, or sores that do not heal, should be brought to the immediate attention of a physician.
Source: American Cancer Society-Orange County Unit; the Orange County Health Department, and the Cancer Surveillance Program of Orange County, Department of Community and Environmental Medicine at UC Irvine.
