Retrospective, Descriptive, Observational Study of Treatment of Multiple Actinic Keratoses With Topical Methyl Aminolevulinate and Red Light: Results in Clinical Practice and Correlation With Fluorescence Imaging

Abstract

Background Actinic keratosis (AK) is one of the most common skin diseases seen in clinical practice. In the last 5 years, several studies assessing the efficacy of photodynamic therapy in the treatment of multiple AKs have been published. Objective We aimed to assess the clinical outcomes of photodynamic therapy in patients with multiple AKs and the correlation of those outcomes with fluorescence imaging. Material and methods In this retrospective, descriptive, observational study of 57 patients treated in our hospital with photodynamic therapy for multiple AKs, we recorded age, sex, and lesion site (face, scalp, and dorsum of the hands). All patients were treated in the same way: methyl aminolevulinic acid (Metvix ®) was applied for 3 hours and the skin then irradiated with red light at 630 nm, 37 J/cm 2, for 7.5 minutes (Aktilite ®). The response, remission duration, tolerance, number of sessions, and fluorescence images were recorded by site. The χ 2 test was used to assess between-site differences and the correlation between fluorescence imaging and clinical response. Results The greatest improvements were obtained for facial lesions; these required fewer sessions and remission lasted longer than lesions at other sites. The treatment was best tolerated on the dorsum of the hands. The fluorescence area and the reduction in intensity on applying treatment were found to be strongly and significantly correlated with the extent of clinical response. Conclusions Overall, the outcomes of treatment of multiple AKs with photodynamic therapy are better for the face than for the scalp and dorsum of the hands. Fluorescence imaging may be an effective tool for predicting response to treatment.