A randomized multicenter study to compare two treatment regimens of topical methyl aminolevulinate (Metvix®)-PDT in actinic keratosis of the face and scalp

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(R) 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/cm(2)). 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.