Correlation between Protoporphyrin IX Fluorescence Intensity, Photobleaching, Pain and Clinical Outcome of Actinic Keratosis Treated by Photodynamic Therapy

Background: Photodynannic therapy (PDT) with Metvix (R) is a good therapeutic option to treat actinic keratosis, but it presents drawbacks (pain, lesion recurrences, heterogeneous outcome), emphasizing the possible need to individualize treatment. Objective: We assessed whether PDT clinical outcome and pain during treatment were correlated with protoporphyrin IX fluorescence intensity and photobleaching. Methods: 25 patients were treated by Metvix PDT. The outcome was evaluated after 1.3 (+/- 0.4), 7.6 (+/- 1.8), 13.2 (+/- 1.2) and 33.6 (+/- 3.0) months. After administration of Metvix, red light (632 +/- 10 nm) was delivered with a light-emitting diode panel device. The outcome was assessed on a cosmetoclinical scale. Results: All patients who showed a fluorescence level before PDT treatment above a certain threshold had a complete recovery at 33.6 (+/- 3.0) months. Conclusion: Our approach could be used to individualize PDT treatment based on the pretreatment fluorescence level, and to predict its long-term outcome. (C) 2013 S. Karger AG, Basel