Skin cancer and Sun damage

According to the Centers for Disease Control and Prevention (CDC) and the American Academy of Dermatology, one million new cases of skin cancer are diagnosed each year. That gives skin cancer the unfavorable distinction of being the most common form of cancer in the United States. As reported by Dr. Darrell S. Rigel of the New York University School of Medicine, the chance for an American to develop melanoma in their lifetime is 1 in 84. Those aren’t the kinds of odds you want to gamble on, at least not when it comes to losing portions of your skin or your life.

Most skin cancers fall into three categories: basal cell carcinomas, squamous cell carci­nomas, and melanomas. Basal cell carcinomas and squamous cell carcinomas are caused by repeated, unprotected sun exposure (Sources: Cancer Epidemiological Biomarkers and Pre­vention, September 2008, pages 2388-2392; Dermatology, February 2008, pages 124-136; American Journal of Clinical Dermatology, May-June 2000, pages 167-179).

However, there is some controversy as to whether melanomas are caused by unprotected sun exposure. Despite the disagreement, what is not in question is that other types of skin cancers are caused by unprotected or prolonged sun exposure. (Sources: Archives of Derma­tology, December 2000, pages 1447-1449; and Journal of the American Medical Association, June 2000, pages 2955-2960.)

As a general theory, scientists believe that exposure to UVA and some UVB radiation triggers mutations in replicating skin cells, causing their genetic coding to go haywire. The cells forget how to maintain the normal cell turnover process because of the radiation damage. Fortunately, nonmelanoma skin cancers are relatively easy to treat if detected in time, and are rarely fatal. Melanomas are a much more dangerous and life-threatening form of cancer.

An article in the Journal of Epidemiology (December 1999, Supplement, pages 7-13) summed up the issue quite nicely: “Skin cancer is the most commonly occurring cancer in humans.. Descriptive studies show that incidence rates of the main types of skin cancer,

basal cell carcinoma, squamous cell carcinoma and melanoma are [highest] in populations in which ambient sun exposure is high and skin transmission of solar radiation is high, suggesting strong associations with sun exposure. Analytic epidemiological studies confirm that exposure to the UV component of sunlight is the major environmental determinant of skin cancers and associated skin conditions and evidence of a causal association between cumulative sun exposure and SCC, solar keratoses and photodamage is relatively straight­forward Complementary to [population and research] data is the molecular evidence

of ultraviolet (UV) mechanisms of carcinogenesis [cancer] such as UV-specific mutations in the DNA of tumor suppressor genes in skin tumors. With increased UV irradiation resulting from thinning of the ozone layer, skin cancer incidence rates have been predicted to increase in the future—unless, as is hoped, human behavior to reduce sun exposure can offset these predicted rises.”

Other than sun protection, you should be aware of some early, telltale signs of skin cancer. Early detection of skin cancer can save your skin and your life. If you perceive a change in your skin that you are not sure about, talk to your doctor; even a minor difference in a mole or a freckle, or a blemish that doesn’t look “normal,” can be an indication of skin cancer.

The five most typical characteristics of skin cancer are:

1. An open sore of any size that bleeds, oozes, or crusts and remains open for three or more weeks. A persistent, nonhealing sore is one of the most common signs of early skin cancer.

2. A reddish patch or irritated area that doesn’t go away and doesn’t respond to cor­tisone creams or moisturizers. Sometimes these patches crust over or flake off, but they never go away completely.

3. A smooth growth with a distinct rolled border and an indented center. It can look like a small blemish or wound, but tends to grow and doesn’t heal.

4. A shiny bump or nodule with a slick, smooth surface that can be pink, red, white, black, brown, or purple in color. It can look like a mole, but the texture and shine are what make it different.

5. A white patch of skin that has a smooth, scarlike texture. The area of white skin can have a taut, clear appearance that stands out from the appearance of the sur­rounding skin.

The American Academy of Dermatology has a list of the “A, B, C, Ds” of identifying skin cancer, as follows:

A Asymmetry: One half of the lesion or suspect area is unlike the other half.

B. Border: There is an irregular, scalloped, or poorly circumscribed border around a suspected skin lesion or mole.

C. Color: Color varies from one area to another, with shades of tan, brown, black, white, red, or blue.

D. Diameter: The area is generally larger than 6 mm (diameter of a pencil eraser).

Updated: September 14, 2015 — 4:29 am