title: Does surface preparation alter ALA uptake in superficial non-melanoma skin cancer in vivo?
abstract: OBJECTIVE
  Photodynamic therapy (PDT) using aminolaevulinic acid (ALA) is widely used in the treatment of non-melanoma skin cancer. Surface preparation of the lesion is commonly performed before application of ALA but the extent of the preparation varies from centre to centre and there has been no study of its effects. The purpose of this study was to examine the effects of surface preparation on the local uptake of ALA by recording fluorescence from accumulated protoporphyrin IX (PPIX).
  
  
  METHODS
  The study was performed on 16 lesions, either superficial basal cell carcinoma (BCC) or Bowen's disease (BD). Each half of the lesion was randomly assigned to (a) no surface preparation or (b) surface preparation (randomly allocated to gentle curettage or abrasion with a spatula). ALA was left for 4 h (BCC) or 6 h (BD). PPIX fluorescence was measured using an excitation wavelength of 405+/-5 nm and emission spectrum recorded using a photodiode array. Spectra were measured (a) before and (b) after surface preparation, (c) immediately before and (d) after laser irradiation at 630 nm.
  
  
  RESULTS
  The ratio of fluorescence after incubation to that before incubation was 6.1+/-1.2 in the non-prepared section. This increased slightly but not significantly to 6.8 +/-1.8 in the prepared section (P<0.1). There was no significant difference between curettage and abrasion. There was also no significant difference in outcome after PDT.
  
  
  CONCLUSIONS
  The clinical assessment agrees with the fluorescence data as no significant difference was seen between prepared and unprepared halves of the lesion 12 months after PDT. Overall our data seem to suggest that for most BCC and BD lesions, surface preparation did not increase ALA uptake.
authors: The Photobiology Unit, Ninewells Hospital & Medical School, University of Dundee, Dundee, UK. h.moseley@dundee.ac.uk
authors: Harry
authors: H
authors: Moseley
authors: Lorenzo
authors: L
authors: Brancaleon
authors: Andrea E
authors: AE
authors: Lesar
authors: James
authors: J
authors: Ferguson
authors: Sally H
authors: SH
authors: Ibbotson
mesh_terms: D000279:Administration, Cutaneous; D000368:Aged; D000369:Aged, 80 and over; D000622:Aminolevulinic Acid / Q000008:administration & dosage; D002280:Basal Cell Carcinoma / Q000175:diagnosis* / Q000473:pathology; D003475:Curettage; D005260:Female; D005453:Fluorescence; D006801:Humans; D008297:Male; D008875:Middle Aged; D017319:Photosensitizing Agents / Q000008:administration & dosage; D012878:Skin Neoplasms / Q000175:diagnosis* / Q000473:pathology; D016896:Treatment Outcome
chemical_list: D017319:Photosensitizing Agents; D000622:Aminolevulinic Acid