TUESDAY, Aug. 9, 2005 (HealthDay News) -- The incidence of nonmelanoma skin cancers appears to be increasing in young men and women, a new study finds.
And women under the age of 40 are bearing the brunt of the rise, with a heightened occurrence of basal cell carcinoma.
Given that people who have had one nonmelanoma skin cancer are much more likely to have another, the public health impact could be considerable.
"Fifty percent of people who get one nonmelanoma skin cancer will get a second in two to three years, and 75 percent of folks who get a second will get a third," said Dr. Leslie J. Christenson, lead author of the study appearing in the Aug. 10 issue of the Journal of the American Medical Association.
"If we start seeing these people getting these cancers in their 20s and 30s, there's going to be an exponential increase in the overall occurrence as they age," said Christenson, a staff dermatologic surgeon and clinical researcher at the Mayo Clinic in Rochester, Minn.
"These are preventable cancers, and people are getting them at a younger and younger age," she added. "Although prevention information is getting out there, our behaviors to prevent these seemingly are not there."
The nonmelanoma skin cancers -- namely basal cell carcinoma and squamous cell carcinoma -- are the most common forms of cancer in the world. The two conditions kill much less often than most cancers, but can cause disfigurement and other complications.
"These are non-aggressive cancers 99 percent of the time," said Dr. Vijay Trisal, an assistant professor of surgical oncology at City of Hope Cancer Center, in Duarte, Calif.
In the United States in 2000, about 800,000 new cases of basal cell carcinoma and 200,000 new cases of squamous cell carcinoma were diagnosed. Prolonged sun exposure -- including tanning bed use -- is the main risk factor.
Scientists had already established that the incidence of nonmelanoma skin cancer is on the rise among people 50 and over. But information on the under-40 crowd had been missing.
To fill that gap, the authors of this study looked at the incidence of nonmelanoma skin cancer between 1976 and 2003 among men and women younger than 40 years old in Olmsted County, Minn.
During this period, the incidence of basal cell carcinoma was 25.9 per 100,000 persons for women and 20.9 for men. The incidence increased significantly during the elapsed 27 years among women (going from 13.4 to 31.6) but not men (where it went only from 22.9 to 26.7).
The incidence of squamous cell carcinoma was similar in men and women, at about 4.1 per 100,000 persons. The incidence increased significantly in both women (from 0.6 to 4.1) and men (from 1.3 to 4.2).
The increase was probably due to a number of factors, including increased exposure to the sun, increased use of tanning beds and increased doctor and patient vigilance, the researchers said.
"We can't say exactly what caused it, but sun exposure is the number-one cause of nonmelanoma skin cancer," Christenson said.
"There were a larger number on the torsos of women than on men and the number of those on the torsos increased over time," Christenson added. "This is a common-sense indication that this is intentional sun exposure from bikinis or low-back, one-piece bathing suits or from sitting in a tanning bed."
Also, the size of cancers detected stayed the same, suggesting that increased surveillance and knowledge were not the only factors at play.
The discrepancies between men and women might also be explained by use of tanning salons, Christenson said.
Trisal agreed. "The increase in young women might be related to tanning booths, which have been shown to have the same kind of damage [as sun exposure]," he said.
And although the researchers looked only at data from Olmsted County, Minn., Christenson believed the data applies to a far larger group of people.
"I would say it's generalizable to the Caucasian population within the U.S., and the Caucasian population at similar latitudes around the world," she said.
More information
For more on skin cancer, visit the American Academy of Dermatology.
