Sunlight may help cancer victims survive

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: Sunlight exposure, a major risk factor for the potentially deadly skin cancer melanoma, may also help victims survive that disease, new research indicates. And a second study indicates that exposure to sunlight may reduce the risk of getting cancer of the lymph glands.

Researchers stress that their findings do not mean people should rush out and start baking in the sun. As for what people should do to gain sunlight’s benefits without its downsides, an editorial accompanying the studies said more research is needed.

“Sunlight, particularly ultraviolet radiation, is a very well established human carcinogen. Nothing in these papers should in any way detract from this message,” said Kathleen M Egan of Vanderbilt University Medical Center.

But the new reports, being published this week in the Journal of the National Cancer Institute (news - websites), do provide important clues to the development of these cancers and some factors that may slow or stop them.

Melanoma has been increasing over the past half-century in developed countries with Caucasian populations, and studies have consistently found exposure to the sun a major risk factor.

However, a new look at 528 melanoma victims over five years also found that increased sun exposure led to increased survivability, according to the study led by Marianne Berwick of the department of internal medicine at the University of New Mexico.

“It’s totally counterintuitive, and we’re trying to investigate it,” said Berwick, noting that she is now doing a similar study of 3,700 melanoma patients worldwide.

“It’s really strange, because sunburn seems to be one of the factors associated with improved survival, and that doesn’t make much sense, so we think sunburn’s a proxy for the kind of sun exposure that leads to melanoma. But there’s so much we need to know,” Berwick said in a telephone interview.

She said Vitamin D, which the skin makes in response to sunlight, may be a factor. Vitamin D can help regulate cell growth and help cells stop unneeded growth through a process called apoptosis.

Another possibility is solar elastosis, a response to sunlight that breaks down collagen in the skin — the same process that causes sun-related wrinkling.

“It may be something in solar elastosis itself... it may be that some physical barrier created by this breakdown of collagen keeps the melanoma from getting into the blood and lymph system,” Berwick said.