Marathoners Risk More Skin Cancers
Lack of Sunscreen and Suppressed Immune Systems Are Factors, Study Shows
Nov. 20, 2006 -- Marathon runners can be proud of their stamina, but all
that time outdoors boosts their risk of skin cancer, including the potentially
deadly malignant melanoma, according to a study in the Archives of
"We are the first to report this," researcher Christina M.
Ambros-Rudolph, MD, tells WebMD in an email interview.
Ambros-Rudolph is a consultant dermatologist at the Medical University of
She and her co-researchers, all runners, conducted the study after caring
for eight ultra-marathon runners with malignant melanoma over the past
Comparing Runners and Nonrunners
In the study, the researchers evaluated 210 marathon runners, men and women,
aged 19 to 71.
They compared the runners' skin cancer risks with those
of 210 men and women matched for age and gender who were not long-distance
All participants underwent a skin cancer exam and answered questions about
personal and family skin cancer history, as well as changes in skin lesions,
sunburn history, sun sensitivity, and physical characteristics such as skin and
Even though more of the nonrunners had higher sun sensitivity, reflected by
their light eyes and sensitive skin types, the runners had more atypical moles
and more lesions called solar lentigines -- often called "liver spots"
-- which are associated with a higher risk of malignant melanoma.
Not surprisingly, the more intense the training regimen, the more likely a
marathon runner was to have the lesions and moles, Ambros-Rudolph found. While
some runners logged about 25 miles a week, others put in more than 44 miles a
No lesions suggestive of malignant melanoma were found, but 24 marathoners
and 14 from the control group were referred to dermatologists to evaluate
growths that looked like nonmelanoma skin cancers (such as basal cell and
squamous cell skin cancers).
What's Behind the Increased Risk?
The study reflects what dermatologists see in practice, says Diane Madfes,
MD, a New York City dermatologist and a spokeswoman for the Skin Cancer
Among her patients who are long-distance runners, Madfes says she has seen
many cases of abnormal moles as well as nonmelanoma
cancers, though not much melanoma, she says.
Greater ultraviolet exposure, of course, is one explanation for the
increased risk, say the Austrian researchers.
Nearly 97% of the runners studied said they wore running shorts and
short-sleeved or sleeveless shirts.
Only 56% said they regularly use sunscreen; nearly 2% never do.
Also, long-term, high-intensity exercise suppresses the immune system, the
Austrian researchers write. They note that patients who have undergone
transplants and had immunosuppressive therapy have an increase in all types of
Reducing the Risk
Ambros-Rudolph advises runners to cover up, train when sunlight exposure is
less intense, and slather on the sunscreen -- in spray or lotion form. An SPF
of 15 or higher is recommended.
The type of product preferred varies by gender, Ambros-Rudolph has observed.
"Men usually hate using lotions, and sprays are quicker to apply and easier
to apply on hairy skin, while women often suffer from dry skin and love lotions
that moisturize at the same time."
Reapplying a water-resistant sunscreen every two hours is important, adds
She suggests runners consider bicycling attire, especially the long-sleeved
shirts made of newer wicking materials that draw away moisture from sweat.
About 62,000 new cases of malignant melanoma are expected this year in the
U.S., along with more than a million nonmelanoma skin cancers, says the
American Cancer Society.
About 8,000 are expected to die this year from malignant melanoma;
nonmelanoma skin cancers will claim about 2,000 lives.