title: Short-term chemical pretreatment cannot replace curettage in photodynamic therapy.
abstract: BACKGROUND
  Guidelines for photodynamic therapy (PDT) recommend pretreatment with curettage/debulking to enhance intracellular formation of protoporphyrin IX (PpIX). However, studies suggest that new chemical pretreatment procedures may replace curettage/debulking.
  
  
  OBJECTIVE
  To investigate how pretreatment with curettage and two combination ointments containing calcipotriol/betamethasone and salicylic acid/betamethasone affect PpIX fluorescence after the application of methyl aminolevulinate MAL and 5-aminolevulinic acid (BF-200 ALA).
  
  
  METHODS
  Four fields on the forearms of 30 healthy volunteers were pretreated with curettage or short-term application of calcipotriol/betamethasone or salicylic acid/betamethasone for 20 min. Two fields were not pretreated, thus serving as reference. After pretreatment, MAL or BF-200 ALA was applied for 24 h, and PpIX fluorescence was measured hourly from 1 to 5 h and after 18, 21 and 24 h.
  
  
  RESULTS
  Curettage significantly enhanced PpIX fluorescence for MAL from 1 to 21 h (P < 0.0041). For BF-200 ALA, curettage enhanced fluorescence from 1 to 5 h (P < 0.000064), while fluorescence was lower from 18 to 24 h. Pretreatment with salicylic acid/betamethasone and calcipotriol/betamethasone before BF-200 ALA application did not increase PpIX fluorescence from 1 to 5 h compared to no pretreatment, and both were significantly inferior to curettage (P < 0.0017 and 0.0024, respectively).
  
  
  CONCLUSIONS
  Curettage significantly enhances PpIX fluorescence from 1 to 5 h and is superior to short-term chemical pretreatment. Our results support curettage as standard pretreatment in PDT.
authors: Department of Dermatology, Bispebjerg Hospital, University of Copenhagen, Copenhagen NV, Denmark.
authors: Christoffer V
authors: CV
authors: Nissen
authors: Department of Dermatology, Bispebjerg Hospital, University of Copenhagen, Copenhagen NV, Denmark.
authors: Stine Regin
authors: SR
authors: Wiegell
authors: Department of Dermatology, Bispebjerg Hospital, University of Copenhagen, Copenhagen NV, Denmark.
authors: Peter Alshede
authors: PA
authors: Philipsen
authors: Department of Dermatology, Bispebjerg Hospital, University of Copenhagen, Copenhagen NV, Denmark.
authors: Hans Christian
authors: HC
authors: Wulf
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000622:Aminolevulinic Acid / Q000031:analogs & derivatives / Q000627:therapeutic use; D000893:Anti-Inflammatory Agents / Q000008:administration & dosage*; D001623:Betamethasone / Q000008:administration & dosage*; D002117:Calcitriol / Q000008:administration & dosage / Q000031:analogs & derivatives*; D003475:Curettage; D003879:Dermatologic Agents / Q000008:administration & dosage*; D004359:Drug Therapy, Combination; D005260:Female; D005453:Fluorescence; D064368:Healthy Volunteers; D006801:Humans; D007641:Keratolytic Agents / Q000008:administration & dosage*; D008297:Male; D008875:Middle Aged; D009824:Ointments; D010778:Photochemotherapy / Q000379:methods*; D017319:Photosensitizing Agents / Q000627:therapeutic use; D011524:Protoporphyrins; D020156:Salicylic Acid / Q000008:administration & dosage*; D055815:Young Adult
chemical_list: D000893:Anti-Inflammatory Agents; D003879:Dermatologic Agents; D007641:Keratolytic Agents; D009824:Ointments; D017319:Photosensitizing Agents; D011524:Protoporphyrins; C055085:calcipotriene; C475457:methyl 5-aminolevulinate; D000622:Aminolevulinic Acid; D001623:Betamethasone; C028025:protoporphyrin IX; D002117:Calcitriol; D020156:Salicylic Acid
keywords: BF-200 aminolevulinic acid; curettage; methyl aminolevulinate; photodynamic therapy; pretreatment