Efficacy of iontophoresis-assisted ablative fractional laser photodynamic therapy with short incubation time for the treatment of actinic keratosis: 12-month follow-up results of a prospective, randomised, comparative trial

Abstract Background Iontophoresis is a transdermal drug-delivery technique that enhances the transport of ionic species across membranes and may have significant benefit for the treatment of actinic keratosis (AK) by ablative fractional laser–primed photodynamic therapy (AFL-PDT). The aims of this study were to compare the efficacy, recurrence rate, cosmetic outcome and safety of iontophoresis-assisted AFL-PDT with 2 h of incubation vs. those of conventional AFL-PDT with 2- and 3-h incubation in patients with facial and scalp AK. Methods Patients were randomly assigned to iontophoresis-assisted AFL-PDT with a 2-h incubation time (group A) and conventional AFL-PDT with a 2-h (group B) and 3-h (group C) incubation time. All patients underwent AFL-PDT, and group A patients were assigned to treatment with iontophoresis after methyl-aminolevulinate (MAL) application. After 2 or 3 h, MAL-applied lesions were irradiated using a red light. Patients were followed up at 1-week, 3 months and 12 months after treatment. Efficacy, cosmetic outcomes and adverse events were assessed. Results In total, 41 patients (160 AK lesions) completed the study and were evaluated. Efficacy was significantly higher in Group A (88.7%) than in Group B (73.2%); the efficacy of groups A and C (92.2%) at 3 months follow-up was comparable. The recurrence rates were not significantly different between the groups at 12 months ( P  = 0.841). The three groups did not differ in terms of cosmetic outcomes and safety. Conclusions Iontophoresis-assisted AFL-PDT showed higher efficacy than AFL-PDT with short incubation time. Iontophoresis may effectively reduce the incubation time in AFL-PDT.