Tanning: Cancer Cause on 'Covered' Skin?
Biggest Jump in Common Skin Cancer on Areas Not Exposed to Everyday Sun
July 22, 2003 -- Each year, some 250,000 Americans are diagnosed with squamous cell carcinoma, the nation's second most common form of skin cancer that typically occurs on the face, ears, and other parts of the body routinely exposed to damaging ultraviolet rays.
But in tracking this type of skin cancer in their own country, Swedish researchers find the biggest jump in cases in recent decades has occurred in a more unlikely location -- skin normally covered by clothing.
Skyrocketing Skin Cancer Cases
They report that since the 1960s, the rate of squamous cell carcinomas -- found more commonly fair-skinned people -- jumped nearly 260% in men and more than 780% in women on regularly sun-exposed skin areas.
Meanwhile, cases on the torso and other skin normally covered by clothing have skyrocketed even more -- a nearly 700% jump in men and 1,575% in women.
"The higher increase in covered, rather than exposed, [body] sites suggests that intentional tanning is the cause," lead researcher Kari Hemminki, MD, PhD, tells WebMD. "UV irradiation reaches covered sites only when exposed intentionally."
Everyday exposure to ultraviolet light (from the sun or tanning parlors) is the single biggest risk for the development of squamous cell carcinoma; other risk factors include arsenic ingestion, exposure to certain chemicals or radiation, organ transplantation, or chronic skin ulcers.
Squamous cell cancer looks like a crusted or scaly skin lesion that grows or becomes an ulcer without healing. A biopsy is usually needed to confirm the diagnosis. Although it usually occurs in sun-exposed areas it can occur anywhere on the body. If left untreated this type of skin cancer can destroy tissue around the tumor and spread throughout the body. Each year, squamous cell cancer causes about 2,500 deaths in the U.S.
Intentional Tanning May -- or May Not Be -- to Blame
But Hemminki says even short bursts of exposure, like that of intentional tanning while on vacation, is the likely explanation for the huge increase in skin cancers on normally covered skin.
"Swedes are active holiday makers to sunny resorts," Hemminki tells WebMD. "Summer time is short and people tend to expose themselves excessively."
He notes that about half of his countrymen travel to sunny climes during vacation, and one in three women and one in five men visit tanning salons. Nearly half of 10,000 Swedes surveyed report having had a sunburn in the past year.
His study, published in the July issue of Archives of Dermatology, tracked more than 50,000 cases of squamous cell carcinomas -- but not other skin cancers -- that occurred between 1961 and 1988.
What it didn't do, says one expert not involved in the study, was examine other potential risk factors that could explain Sweden's boost in all squamous cell carcinomas.
"There's no disputing that UV rays can cause squamous cell carcinomas; they're not the only cause," says Ella L. Toombs, MD, a Washington dermatologist and former FDA medical officer.