Sunlight May Help Cancer Victims Survive

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Sunlight May Help Cancer Victims Survive

 

Tue Feb 1, 5:30 PM ET

 

Health - AP

 

By RANDOLPH E. SCHMID, Associated Press Writer

 

WASHINGTON - Sunlight exposure, a major risk factor

for the potentially deadly skin cancer melanoma, may

also help victims survive that disease, new research

indicates.

 

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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 - web

sites), 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.

 

In the second study, a research team led by Karin

Ekstrom Smedby of the Karolinska Institute in

Stockholm, Sweden, studied 3,000 lymph cancer patients

and a similar number of people without lymph cancer in

Denmark and Sweden.

 

They found that increased exposure to ultraviolet

radiation through sunbathing and sunburns resulted in

a reduced incidence of non-Hodgkin's lymphoma.

 

Vanderbilt's Egan, who was not involved in either

research team, said it's unlikely to be sunlight

itself that is an explanation of these findings.

 

The scientific community is converging on the idea

that Vitamin D is likely to be a protective agent in

cancer, she said in a telephone interview.

 

" It's long been known that Vitamin D is a critically

important agent in bone health, " she noted. " More

recently it has become increasingly obvious that

Vitamin D has important regulatory functions in the

cell, in terms of cell division, " she said.

 

 

 

In an accompanying commentary in the journal, Egan and

co-researchers at Vanderbilt say the two findings are

of particular interest because non-Hodgkin's lymphoma

is suspected of being caused in a way similar to skin

cancer.

 

More than a million cases of skin cancer are

attributed to sun exposure annually in the United

States, with about 54,000 cases of melanoma diagnosed

each year, noted the Vanderbilt researchers, which

also included Jeffrey A. Sosman and William J. Blot.

 

Berwick's research was supported by the U.S. National

Cancer Institute while Smedby's was funded by the U.S.

National Institutes of Health (news - web sites), the

Swedish Cancer Society, Plan Denmark and the Danish

National Research Foundation.

 

___

 

On the Net:

 

Journal of the National Cancer Institute:

http://jncicancerspectrum.oupjournals.org

 

(Corrects 11th paragraph to collagen from collages.)

 

 

 

 

 

 

 

 

 

 

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