title: Correlation between protoporphyrin IX fluorescence intensity, photobleaching, pain and clinical outcome of actinic keratosis treated by photodynamic therapy.
abstract: BACKGROUND
  Photodynamic therapy (PDT) with Metvix® 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.
  
  
  CONCLUSIONS
  Our approach could be used to individualize PDT treatment based on the pretreatment fluorescence level, and to predict its long-term outcome.
authors.affiliation: Medical Photonics Group, Swiss Federal Institute of Technology, SB-ISIC, Lausanne, Switzerland.
authors.forename: Filippo
authors.initials: F
authors.lastname: Piffaretti
authors.forename: Matthieu
authors.initials: M
authors.lastname: Zellweger
authors.forename: Behrooz
authors.initials: B
authors.lastname: Kasraee
authors.forename: Jérôme
authors.initials: J
authors.lastname: Barge
authors.forename: Denis
authors.initials: D
authors.lastname: Salomon
authors.forename: Hubert
authors.initials: H
authors.lastname: van den Bergh
authors.forename: Georges
authors.initials: G
authors.lastname: Wagnières
mesh_terms: D000368:Aged; D000622:Aminolevulinic Acid / Q000031:analogs & derivatives / Q000627:therapeutic use; D005453:Fluorescence; D006801:Humans; D055623:Keratosis, Actinic / Q000188:drug therapy*; D008875:Middle Aged; D010146:Pain / Q000139:chemically induced*; D010147:Pain Measurement; D038761:Photobleaching / Q000187:drug effects / Q000528:radiation effects*; D010778:Photochemotherapy / Q000009:adverse effects; D017319:Photosensitizing Agents / Q000627:therapeutic use; D011524:Protoporphyrins / Q000032:analysis*; D016896:Treatment Outcome
chemical_list: D017319:Photosensitizing Agents; D011524:Protoporphyrins; C475457:methyl 5-aminolevulinate; D000622:Aminolevulinic Acid; C028025:protoporphyrin IX