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Scientists Find Sun Exposure May Improve Cancer Survival

A new study suggests that the benefits of sun exposure may outweigh the risks of developing skin cancer. According to the findings, the sun's rays, which are known for causing a deadly form of skin cancer, appear to improve cancer survival for other types of the disease. VOA's Jessica Berman reports.

Malignant melanoma is an aggressive form of skin cancer that primarily strikes fair-skinned people and frequently leads to death. Melanoma has been linked to intense sun exposure. The incidence of melanoma is highest in countries closest to the equator, such as Australia, which receive the greatest amount of solar radiation.

But scientists have long wondered about the benefits of sunlight, which triggers vitamin D production in humans. Vitamin D is necessary for a healthy heart, strong bones, and a properly functioning immune system.

Richard Setlow is a biophysicist at the U.S. Department of Energy's Brookhaven National Laboratory in New York and co-author of a study published this week in the Proceedings of the National Academy of Sciences. The study compared the risks and benefits of sun exposure on human health. Setlow says the benefits may outweigh the risks.

"It turns out that the exposure to sunlight is more important than the fact that sunlight exposure can give rise to skin cancer," he said.

In the study, Setlow and a team of researchers from Norway analyzed cancer data from Australia, New Zealand, Sweden, Norway, Denmark and the United Kingdom among populations with similar skin types.

While they expected to see more skin cancer in people who lived closest to the equator, investigators found more cases of internal cancers as well, including cancer of the breast, colon, prostate and lung.

But researchers also discovered that patients who live closer to the equator were more likely to survive their disease than cancer patients in more northern latitudes, with less sunlight.

Setlow says the data show a survival advantage for all cancer types, including deadly skin cancer, even though melanoma is caused by excessive sun exposure.

"Sunlight exposure increases the incidence of malignant melanoma, for example," he said. "That could be a lethal cancer. Nevertheless, more sunlight exposure reduces the death rate from skin cancer from melanoma even though it induces it."

Setlow says two, fifteen-minute exposures to outdoor sunshine everyday without a sun cream is all that is required to get the full health benefit.