title: Surgical scar remodelling after photodynamic therapy using aminolaevulinic acid or its methylester: a retrospective, blinded study of patients with field cancerization.
abstract: BACKGROUND
  Photodynamic therapy (PDT) is a nonsurgical alternative to conventional tumour excision for nonmelanoma skin cancers (NMSCs).
  
  
  OBJECTIVE
  We evaluated whether patients with field cancerization (multiple NMSCs) treated with aminolaevulinic acid (ALA) or its methylester (MAL) for that indication had PDT-induced changes in surgical scars in the treatment field.
  
  
  METHODS
  Six adult patients with multiple NMSCs and a total of 21 scars from previous excisions were studied in a retrospective blinded evaluation from clinical photographs of scar response to ALA/MAL-PDT. After a 3-h application of topical 20% ALA or 16·8% MAL under occlusion, each field was irradiated with 635-nm light-emitting diode light at the fluence of 200Jcm(-2) . Patients underwent one to three PDT sessions per field at ∼1month intervals, to fields that included scars on the back, thigh, arms and neck. Pre- and post-treatment digital photographs of scars were combined into 92 pairs that were independently and blindly evaluated by three board-certified dermatologists. This study was performed at our academic practice at the Massachusetts General Hospital.
  
  
  RESULTS
  PDT produced a statistically significant improvement in scar appearance. The degree of improvement correlated with the number of treatment sessions (two or three treatments; P<0·05). Improvement after a single treatment was not statistically different from baseline ratings (P=0·99).
  
  
  CONCLUSIONS
  Surgical scar remodelling and clinical improvement may be accomplished via ALA/MAL-PDT, but may require repeated treatment sessions. Larger, prospective studies are necessary to confirm the effectiveness of PDT for this indication.
authors.affiliation: Wellman Center for Photomedicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA.
authors.forename: F H
authors.initials: FH
authors.lastname: Sakamoto
authors.forename: L
authors.initials: L
authors.lastname: Izikson
authors.forename: Z
authors.initials: Z
authors.lastname: Tannous
authors.forename: D
authors.initials: D
authors.lastname: Zurakowski
authors.forename: R Rox
authors.initials: RR
authors.lastname: Anderson
mesh_terms: D000279:Administration, Cutaneous; D000328:Adult; D000368:Aged; D000622:Aminolevulinic Acid / Q000008:administration & dosage*; D000704:Analysis of Variance; D002921:Cicatrix / Q000188:drug therapy* / Q000473:pathology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010778:Photochemotherapy / Q000379:methods*; D010781:Photography; D017319:Photosensitizing Agents / Q000008:administration & dosage*; D011897:Random Allocation; D012189:Retrospective Studies; D012878:Skin Neoplasms / Q000188:drug therapy* / Q000473:pathology
chemical_list: D017319:Photosensitizing Agents; D000622:Aminolevulinic Acid