Photodynamic therapy with topical methyl aminolevulinate for actinic keratosis: Results of a prospective randomized multicenter trial

Background: Photodynamic therapy (PDT) is a promising new treatment modality for actinic keratoses. Methyl aminolevulinate (MAL) (Metvix, PhotoCure, Oslo, Norway) leads to selective accumulation of photoactive porphyrins in premalignant skin lesions and makes the lesions susceptible to phototoxic effects on illumination with red light. Objective. This multicenter, randomized, double-blind study compared complete response rates, cosmetic outcome, and patient satisfaction for PDT with cream containing 160 mg/g MAL or placebo cream in the treatment of actinic keratoses. Methods: After application of the cream under occlusion for 3 hours, the lesions were illuminated by noncoherent red light (570-670 nm, light dose 75 j/cm(2)). Treatment was repeated after 1 week and response was assessed 3 months later. A total of 80 patients were randomized into the study, 42 in the active and 38 in the placebo group. Results: Complete lesion response rate was higher after MAL PDT than placebo, 89% versus 38% per protocol analysis (P = .001). An excellent or good cosmetic outcome was reported in more than 90% of patients treated with MAL. Conclusion: In this small Study, PDT using topical MAL was a safe and effective treatment for actinic keratoses with excellent cosmetic outcome. It is a promising treatment that could benefit from further study.