Mikael Tarstedt, Inger Rosdahl, Berit Berne, Katarina Svanberg, Ann-Marie Wennberg
DOI: 10.1080/00015550510032887

Photodynamic therapy (PDT) with topical methyl aminolevulinate (MAL) administered in two treatment sessions separated by 1 week is an effective treatment for actinic keratoses. This open prospective study compared the efficacy and safety of MAL-PDT given as a single treatment with two treatments of MAL-PDT 1 week apart. Two hundred and eleven patients with 413 thin to moderately thick actinic keratoses were randomized to either a single treatment with PDT using topical MAL (regimen I; n =105) or two treatments 1 week apart (regimen II; n =106). Each treatment involved surface debridement, application of Metvix® cream (160 mg/g) for 3 h, followed by illumination with red light using a light‐emitting diode system (peak wavelength 634±3 nm, light dose 37 J/cm2). Thirty‐seven lesions (19%) with a non‐complete response 3 months after a single treatment were re‐treated. All patients were followed up 3 months after the last treatment. A total of 400 lesions, 198 initially treated once and 202 treated twice, were evaluable. Complete response rate for thin lesions after a single treatment was 93% (95% CI=87–97%), which was similar to 89% (82–96%) after repeated treatment. Response rates were lower after single treatment of thicker lesions (70% (60–78%) vs 84% (77–91%)), but
improved after repeated treatment (88% (82–94%)). The conclusion of this study is that single treatment with topical MAL‐PDT is effective for thin actinic keratosis lesions; however, repeated treatment is
recommended for thicker or non‐responding lesions.