title: Our PDT experience in the treatment of non-melanoma skin cancer over the last 7 years.
abstract: BACKGROUND
  Topical photodynamic therapy (PDT) with 5-aminolevulinic acid (ALA) was first described by Kennedy et al. in 1990; currently, accumulated evidence shows that topical PDT is effective in the treatment of actinic keratoses, Bowen's disease and superficial basal cell carcinoma, being potentially advantageous where size, anatomical location or number of lesions limit the efficacy and/or the acceptability of conventional therapies. It involves the use of photosensitizing drugs and the administration of an appropriate light source to activate the sensitizing agent, which leads to the production of activated oxygen species for tissue destruction. The topically administered prodrug 5-ALA is converted within cells into the active photosensitizer protoporphyrin IX, via haem cycle, with preferential accumulation in tumour cells.
  
  
  METHODS
  The authors describe their experience with topical PDT, using 20% 5-ALA and two different incoherent light sources, 'Waldman 1200 L' and 'VersaLight', in the treatment of non-melanoma skin cancer and precursor lesions. More than 100 patients were treated since 1997, with up to a 7-year follow-up period.
  
  
  RESULTS
  Cases are illustrated and results are presented and discussed in the light of the relevant Literature.
  
  
  CONCLUSIONS
  The study suggests that 5-ALA PDT is effective in the treatment of superficial skin cancer and premalignant lesions.
authors.affiliation: Dermatology Department, Hospital do Desterro, Lisbon, Portugal. jbat@netcabo.pt
authors.forename: J
authors.initials: J
authors.lastname: Baptista
authors.forename: C
authors.initials: C
authors.lastname: Martinez
authors.forename: L
authors.initials: L
authors.lastname: Leite
authors.forename: M
authors.initials: M
authors.lastname: Cochito
mesh_terms: D000287:Administration, Topical; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000622:Aminolevulinic Acid / Q000008:administration & dosage / Q000627:therapeutic use*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D010778:Photochemotherapy / Q000379:methods*; D017319:Photosensitizing Agents / Q000008:administration & dosage / Q000627:therapeutic use*; D012878:Skin Neoplasms / Q000473:pathology / Q000628:therapy*; D016896:Treatment Outcome
chemical_list: D017319:Photosensitizing Agents; D000622:Aminolevulinic Acid