VALUE OF A 2ND FREEZE-THAW CYCLE IN CRYOTHERAPY OF COMMON WARTS

A study of open, randomized, parallel-group design was performed to investigate the impact of a second freeze-thaw cycle on the cure rate, at 3 months, from cryotherapy of common warts on the hands and feet. Cryotherapy was performed at 3-week intervals, and subjects were randomized to receive either one or two freeze-thaw cycles. In addition, all subjects used keratolytic wart paints throughout the study, and plantar warts were pared prior to freezing. Three hundred subjects were recruited. At 3 months, 124 were cured, 83 were not cured, and 93 had defaulted. Among those who did not default the cure rate was 57% from the single freeze technique, and 62% from the double freeze technique, a difference of 5% (P = 0.53, 95% CI -8.1-18.6). Separate analyses for subjects with warts on the hands and on the feet demonstrated no effect of double freezing on hand warts. In contrast, for plantar warts, the cure rate was 41% from single freezing and 65% for double freezing, a difference of 24% (P = 0.04, 95% CI 2.9-44.4). The use of a double freeze-thaw cycle confers little or no advantage over a single freeze in the treatment of hand warts, but may be considerably more effective for plantar warts.