The impact of occlusive vs non-occlusive application of methyl aminolevulinate on the efficacy and tolerability of daylight photodynamic therapy for actinic keratosis.

ABSTRACT

BACKGROUND: Conventional photodynamic therapy (c-PDT) is an effective treatment for actinic keratoses (AKs) and nonmelanoma skin cancer which exploits the photosensitizing properties of methyl aminolaevulinate (MAL). Daylight photodynamic therapy (DL-PDT) is an alternative to c-PDT which does not require the application of MAL in occlusion and that is better tolerated by patients. The impact of occlusion on the efficacy of DL-PD has not been investigated by previous studies. OBJECTIVE: To compare the efficacy and tolerability of occlusive and non-occlusive DL-PDT. METHODS: We conducted a prospective intraindividual left/right comparison study. AKs of the face or scalp were marked in two symmetrical treatment areas. The two target areas were randomly assigned to DL-PDT with occlusive and non-occlusive application of MAL. The efficacy and cosmetic outcome were determined by a "blinded" investigator. RESULTS: Lesions in occluded areas showed a better response in the clearance rate of the lesions (65.5% vs 35.0 %, p < 0.001 %), and cosmetic outcome (P < 0.001). There was no difference in phototoxicity or pain between occluded and non-occluded areas. CONCLUSION: The occlusive application of MAL improves the efficacy of DL-PDT in clearing AKs and does not increase the incidence of side effects.