Dec. 30, 2002 -- It's now official: Ol' Sol ranks up there with tobacco, pollution, and other scientifically proven toxins as a bona-fide, government-decreed substance known to cause cancer. For the first time, broad spectrum ultraviolet radiation is listed as a "known" rather than a "probable" cause of cancer in humans.
"Broad spectrum ultraviolet radiation produced by the sun and artificial light sources" such as tanning beds and sun lamps has been added to the latest installment of the National Institute of Environmental Health Sciences' (NIEHS) bi-annual Report on Carcinogens (RoC), released Dec. 11 by the Department of Health and Human Services. It's one of four new entries added to a list of 228 substances known to cause cancer in humans.
Not that the news is surprising to most dermatologists, who have recommended for decades to reduce exposure to UV radiation by wearing sunscreen and limit time under sunlight and tanning booths to help prevent skin cancer. Skin cancer is the most common cancer in the U.S. More than 1 million new cases are diagnosed each year, and it is estimated that one American dies every hour from melanoma, the deadliest form, reports the American Academy of Dermatology.
"Numerous studies have shown time and time again that overexposure to ultraviolet radiation can lead to skin cancer," says dermatologist and academy president Fred F. Castrow II, MD, in a prepared statement. "This report should be a wake-up call to people who continue to tan -- through natural sunlight or artificial sources -- despite our repeated warnings."
But there are those who dispute the listing -- namely, those in the tanning industry.
"We don't wish to cheerlead for sun tanning or sun exposure, whether indoors or outdoors, because anything taken to excess is not good for you -- water and air, for that matter," says Michael Stepp, chief executive officer for Wolff System Technology, a supplier of lamps for indoor tanning beds. "But it's been quite a long season of negative reports on UV exposure where a lot of the benefits are overlooked or ignored." Those benefits include maintaining adequate amounts of vitamin D from sunlight, which is necessary for bone health.
Another Wolff System spokesman, Daryl Toor, says that most of the science used to make the RoC listing was based on studies done on rats and other laboratory animals. "Drawing conclusions about humans based on fish/mice studies is difficult, if not impossible, primarily because humans have repair mechanisms that are not present in 'sensitive' lab animals" who lack melanin, a natural sunscreen produced by humans.
Toor also tells WebMD that the tanning industry was not allowed to present its own data on the benefits of UV exposure through sunlight and artificial light sources. "Even though the laws of the [agency that compiles the RoC] are supposed to encourage outside opinions, it never contacted anyone in the industry for any input," he tells WebMD. "We were not included or allowed to give outside opinion."
Not so, say those involved in compiling and distributing the RoC, which was mandated by Congress in 1978 as part of the Public Health Service Act.
"For something to be listed as a known human carcinogen, there has to be sufficient evidence from studies on humans indicating a cause or relationship between exposure to the material and human cancer," says Bill Jameson, PhD, of the National Toxicology Program, and the scientist in charge of compiling the RoC. "There is a wealth of information (on the dangers of UV overexposure) from studies on people who have been exposed to radiation -- especially those who get sunburns." The National Toxicology Program is a division of the NIEHS, the official delegate of the RoC, which updates its listing of known carcinogens every two years.
"In order to be listed on RoC, scientific data is presented over a two-year period before three separate panels comprising of recognized experts -- including dermatologists, researchers and other scientists, many of whom are not affiliated with various government health agencies that compile and review the carcinogens list," Jameson tells WebMD. "The data is presented before these panels in open and public settings, and there are three or four announcements of these meetings. The suntanning industry was aware of these meetings and gave us input during the process."
The data presented to these committees come from clinical trials and other scientific studies published in peer-reviewed medical journals. There are eight to 12 members of each committee, and "each committee voted unanimously that broad spectrum UV radiation should be considered a 'known' human carcinogen," notes NIEHS spokesman Bill Grigg.
"We have been in touch with the tanning industry for these whole two years -- ever since we first considered placing broad spectrum UV radiation on the known carcinogens list, based on numerous clinical studies. They have had the opportunity to present data," Grigg tells WebMD. "In fact, I recall attending a session with one of the committees evaluating the data, and two or three of tanning industry representatives spoke to the board."
In addition to UV radiation, other new RoC entries include wood dust, believed to boost risk of cancers of the nasal cavities and sinuses; steroidal estrogens, commonly used in estrogen replacement therapy to treat menopause and in oral contraceptives and associated with an increased chance of breast cancer; and nickel compounds used in batteries and ceramics that are linked to lung and nasal cancers.