Last month the American Association for the Advancement of Science suggested suntans and sunburns may help prevent melanoma, and regular use of sunscreen may increase the risk of developing the disease.
"The information was unfounded and ridiculous," said Dr. Jean Gordon, a Mountain View dermatologist. "Their study only covered 10 years, and melanomas often develop 20 or more years after excessive sun exposure," Gordon said.
The American Cancer Society expects 41,600 new cases of melanoma and 7,300 deaths from it this year. Virtually every piece of evidence the Society collected linked melanoma to sun exposure once in a lifetime.
The debate over skin disorders continues whether the greatest danger to skin comes with a slow, steady exposure or from having suffered blistering sunburns in childhood.
Gordon, a Los Altos resident, said that heredity can create an above-average melanoma risk due to family history of fair skin and abnormal moles. Other risks include more than three extensive blistering sunburns before the age of 20 and three or more years spent in an outdoor job as a teen.
"Anyone who has two of those three risk factors should have a yearly exam," Gordon said. "Atypical moles are the most important risk factor. People with one or two have twice the lifetime melanoma risk of those without such moles. Sun worshipping, brief attire and ozone depletion all increase our exposure to ultraviolet light. Melanoma now affects one in 80 people."
Gordon, who received her medical degree from Stanford University, is a strong believer in sunscreen usage. It not only can minimize painful sunburn, but can also limit photo-aging and forms of skin cancer. She said that tanning booths should be avoided and kids playing outside should use a sunscreen.
"Mothers should put a tube of sunscreen on the breakfast table and have the children put it on after they eat their breakfast," Gordon said.
Gordon said that UVA (ultraviolet-A), the long solar rays, penetrate the skin deeply and are the chief culprit behind wrinkling, leathering and photo-aging. The UVB (ultraviolet-B), are the short solar rays that are more potent in producing sunburn and considered the main cause of squamous cell carcinomas.
"Sunscreens chemically absorb UV rays, sunblocks physically deflect them. The SPF (sun protection factor) measures the length of time a product protects against skin reddening from UVB. Most broad-spectrum sunscreens and sunblocks with an SPF of 15 or higher do a good job against UVB and short UVA rays.
"If it takes 20 minutes without protection to begin reddening, using an SPF 15 sunscreen theoretically prevents reddening 15 times longer or about 5 hours. To maintain the SPF, reapply sunscreen every two hours," Gordon said.
The Skin Cancer Foundation cautions that no matter how careful you are about sun protection, some harmful ultraviolet radiation will still get through to your skin.
"Wearing wet clothing over you body is no help because it allows radiation to go through, especially a wet T-shirt on the beach," Gordon said. "Wear sun-protective clothing, sunglasses, stay in the shade and out of the sun from 10 a.m. to 4 p.m."
Gordon practices aesthetic and general dermatology. Her office is at 2204 Grant Road, Suite 104, Mountain View. For more information, call 938-6559.