"This data is really strong," said Dr. Otis W. Brawley, chief medical officer of the American Cancer Society. "We have been very concerned for a long time that tanning beds clearly cause cancer and we have been recommending against their use."
These findings may renew calls to better regulate indoor tanning, according to the study authors.
"A national ban for those under 18 is a first step, because that is the group at highest risk," Linos said, adding that many states are already doing this.
Representatives from the tanning industry balked at the idea of bans and stiff regulations for a practice they said comes with health benefits that may offset the risks.
"Tanning beds are a good source of vitamin D, which is associated with many health benefits," said John Overstreet, executive director of the Washington D.C.-based Indoor Tanning Association.
Such an argument may not be enough to convince many health experts, however. In 2009, the World Health Organization placed all forms of indoor tanning in the same category as such cancer-causing agents as tobacco smoke and asbestos.
"Vitamin D is important for general health, and can be obtained both through sunlight but also through the diet," Linos said. "The risks of indoor tanning outweigh the benefits, especially for young people."
Moreover, she added, tanning beds are typically used by young healthy women who are not at risk for Vitamin D deficiency and conditions linked to low vitamin D levels.
Benz said she feels tanning beds should be banned.
"There's no way on earth we should let teenagers use them," she said. "I think a lot of tanning bed [parlors] are turning their heads and aren't checking their IDs."
There are other options to tanning, Benz said. Since her experience with skin cancer, she has started an airbrush tanning business -- an alternative, she said, to the tanning bed. On one occasion, Benz discovered a suspicious lesion on the back of one of her regular clients, which turned out to be a basal cell skin cancer.
"She said, 'If you hadn't pointed it out, I never would have seen it,'" Benz said.