Microwave therapy for the treatment of resistant plantar warts: a randomized, placebo-controlled clinical trial

Plantar warts, or verrucae plantares, are skin lesions on the soles of the feet caused by human papillomavirus (HPV). These warts are prevalent and affect up to 33% of children and 3.5% of adults. While they may regress spontaneously, plantar warts often persist and resist conventional treatments such as excision, cryotherapy, and laser procedures.This study investigated microwave-induced hyperthermia as a treatment for recalcitrant plantar warts. The study was conducted at a dermatology practice in Lübeck, Germany. Thirty-two adult patients with long-lasting, treatment-resistant plantar warts were randomly assigned to either a treatment or placebo group. The treatment group received microwave therapy (Swift^®, Emblation Medical Ltd., UK), while the placebo group underwent sham treatment with a ruby laser (Sinon^®, Alma Lasers Ltd., Israel). Treatments were administered every four weeks, for a total of 3 treatments, with a follow-up period of 3 months after the third session. The primary outcome was complete wart clearance.Of the 32 participants, 6 dropped out, leaving 28 for analysis. Complete clearance was achieved in 27.3% of the treatment group (3/11) compared to 0% of the placebo group (p = 0.032). Six patients in the treatment group achieved a partial response ranging from 41.1 to 88.4% of the total wart area, with a partial clearance rate of 54.5% versus 13.3% in the placebo group. The average pain score for the microwave treatment group was 5.44.Microwave therapy has proven to be superior to placebo treatment. The clearance rate in this study was lower than that reported in previous uncontrolled studies, potentially due to differences in treatment protocols. The pain level and cost of consumables present challenges. However, further studies are needed to optimize the protocol and assess its efficacy in larger populations and for different wart types.