University of Iowa News Release
Dec. 16, 2003
UI Study Indicates Sunscreen Does Not Increase Melanoma Risk
Sunscreen use is not linked to an increased risk for melanoma, according to University of Iowa researchers who reviewed 18 studies on sunscreen and this deadly type of skin cancer. The investigators saw limitations among several studies that had found an association between sunscreen use and increased melanoma.
Some of the studies analyzed did not take into account people's risk factors for the disease. The review article appears in the Dec. 16 issue of the Annals of Internal Medicine.
An estimated 54,200 people in the United States will be diagnosed with melanoma in 2003, and nearly 7,600 people will die from the disease. Nationwide, melanoma cases are occurring at a faster rate than any other type of cancer.
"Our review suggests that sunscreen use is not a risk factor for melanoma," said Leslie Dennis, Ph.D., assistant professor of epidemiology in the UI College of Public Health and one of the study's authors.
By reviewing studies dating back to the 1960s, the researchers found that some studies did not properly account for sun sensitivity -- or the possibility that people at a higher risk of getting skin cancer use sunscreen more than people with less risk.
"People who are more sun-sensitive tend to have fair skin, burn easily or be unable to tan, so if you don't account for that, you end up finding sunscreen use associated with more melanoma," said Dennis, who also is a member of the Holden Comprehensive Cancer Center at the UI. "However, when you properly adjust melanoma risk for sun sensitivity, you find that using sunscreen does not harm."
Most studies did not include data on newer sunscreens with features such as sun protection factor (SPF). Many studies were based on data gathered before the availability of sunscreens with both blockers against ultraviolet radiation A and B (UVA and UVB) and water-resistance.
While the review indicates that sunscreen does not harm, and the team found some studies in which sunscreen was associated with melanoma protection, it is too early to conclusively say there is a protective effect.
"Once sunscreens with SPF and other advanced blockers have been out for at least another 10 years, we can look at their use and draw conclusions. Hopefully, we will see that sunscreen use actually is protective," Dennis said.
Meanwhile, people are urged to use sunscreens according to the directions.
"We still do not recommend that you use sunscreen simply to prolong sun exposure, as that may put you at risk. Most people do not reapply sunscreen when they should," Dennis said.
A typical six-ounce bottle of sunscreen, if applied correctly to a person's entire body, would provide only one application, explained Marta VanBeek, M.D., study co-author and an assistant professor of dermatology in the UI Roy J. and Lucille A. Carver College of Medicine and a dermatologist with UI Hospitals and Clinics.
"Although it may be impractical to apply that large amount of sunscreen, the important thing to remember is that we need to apply more than we think and reapply frequently," VanBeek said.
Melanoma occurs when skin cells that produce melanin, or brown pigment, are damaged. Risks factors for the disease include a family history of melanoma, large number of moles or freckles, sun sensitivity, and exposure to UV radiation from sunlight or sunlamps and tanning beds.
The third UI contributor to the study was Laura Beane Freeman, Ph.D., who was a doctoral student in epidemiology at the UI College of Public Health and now works at the National Cancer Institute (NCI).
The study was funded in part by an NCI grant.
The Holden Comprehensive Cancer Center is Iowa's only National Cancer Institute (NCI)-designated comprehensive cancer center. NCI-designated comprehensive cancer centers are recognized as the leaders in developing new approaches to cancer prevention and cancer care, conducting leading edge research and educating the public about cancer.
University of Iowa Health Care describes the partnership between the UI Roy J. and Lucille A. Carver College of Medicine and UI Hospitals and Clinics and the patient care, medical education and research programs and services they provide. Visit UI Health Care online at www.uihealthcare.com.
STORY SOURCE: University of Iowa Health Science Relations, 5137 Westlawn, Iowa City, Iowa 52242-1178
MEDIA CONTACT: Becky Soglin, Writer, 319-335-6660, firstname.lastname@example.org
PHOTOS: A photo of Dennis is available for downloading at http://www.public-health.uiowa.edu/academics/faculty/leslie_dennis.html. A photo of VanBeek is available for downloading at http://tray.dermatology.uiowa.edu/MVB.htm.