At 13 weeks, 240 people remained in the trial. The cure rates for common warts (treated in 116 people) was 49 percent for freezing, 15 percent for those receiving salicylic acid and 8 percent for the wait-and-see group.
For the 124 people treated for plantar warts, the cure rate was similar whether they got freezing or salicylic acid. Eleven of 37 people who underwent cryotherapy experienced a "cure" -- disappearance of the wart for 13 weeks -- compared to 14 of 43 people treated with salicylic acid. Plantar warts resolved on their own in 10 of the 44 patients in the wait-and-see group.
Bruggink said his team will next look at combination treatments for plantar warts.
The Dutch results didn't impress Dr. Steven Feldman, professor of dermatology, pathology and public health sciences at Wake Forest University Baptist Medical Center, Winston-Salem, N.C., who reviewed the study.
"Well, there's clearly one thing they proved: We still need a good treatment for warts," Feldman said. "Most patients did not respond to any of these treatments."
And side effects, including pain, blisters and scarring, were reported, he noted, especially for those who got the freezing therapy.
Another issue, Feldman said, is that salicylic acid, used at home, may not have been used as often as recommended, potentially limiting its effectiveness. On the other hand, people in the freezing treatment group had to return to the office every two weeks, he said, an inconvenience.
There's cost to consider, too: While freezing can cost patients hundreds of dollars, salicylic acid runs to the "tens of dollars" only, Feldman said.
And while the cure rates for freezing were better at 13 weeks, Feldman wonders if the warts might still come back later.
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