title: Photodynamic therapy with violet light and topical 6-aminolaevulinic acid in the treatment of actinic keratosis, Bowen's disease and basal cell carcinoma.
abstract: BACKGROUND
  Most clinical studies using photodynamic therapy (PDT) with topical application of delta-aminolaevulinic acid (delta-ALA) use red light because it allows greater depth of penetration. However, given the porphyrin-like spectrum of delta-ALA-induced photosensitivity, violet light provides a maximal overlap with the excitation spectrum of protoporphyrin IX, meaning that PDT with violet light uses less light energy to induce the phototoxic reaction.
  
  
  OBJECTIVE
  To study the efficacy of violet light in combination with topical delta-ALA PDT in the treatment of pre-malignant and malignant skin lesions.
  
  
  METHODS
  Eight hours after 20% delta-ALA was applied topically, photoirradiation was performed with an incoherent light source (Philips HPM-10, 400 W) emitting predominantly violet light (400-450 nm). Lesions received 10-20 J/cm2 during an exposure time of 30 min. The 38 subjects treated included three with basal cell naevus syndrome with multiple (> 30) superficial and nodular basal cell carcinomas (BCCs), one subject had multiple lesions of Bowen's disease, involving 50% of the scalp, and the remaining 34 subjects presented a total of 35 superficial BCCs, 10 nodular BCCs, four large solar keratoses and five solitary lesions of Bowen's disease.
  
  
  RESULTS
  Complete remission both clinically and histologically was seen after a single treatment in 82% of the superficial BCCs (100% after a second treatment), 50% of the nodular BCCs, one of the four solar keratosis lesions (partial remission in the other three) and 90-100% of the solitary lesions of Bowen's disease.
  
  
  CONCLUSIONS
  delta-ALA PDT using violet light appears to be a well tolerated and effective alternative treatment for premalignant and malignant skin lesions, especially when there are multiple lesions or large patches comprising a large area of skin.
authors.affiliation: Department of Dermatology, University Medical Center Utrecht, The Netherlands.
authors.forename: A T
authors.initials: AT
authors.lastname: Dijkstra
authors.forename: I M
authors.initials: IM
authors.lastname: Majoie
authors.forename: J W
authors.initials: JW
authors.lastname: van Dongen
authors.forename: H
authors.initials: H
authors.lastname: van Weelden
authors.forename: W A
authors.initials: WA
authors.lastname: van Vloten
mesh_terms: D000287:Administration, Topical; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000622:Aminolevulinic Acid / Q000008:administration & dosage; D001913:Bowen's Disease / Q000175:diagnosis / Q000188:drug therapy*; D002280:Basal Cell Carcinoma / Q000175:diagnosis / Q000188:drug therapy*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007642:Keratosis / Q000175:diagnosis / Q000188:drug therapy*; D008297:Male; D008875:Middle Aged; D010778:Photochemotherapy / Q000379:methods*; D017319:Photosensitizing Agents / Q000008:administration & dosage; D012878:Skin Neoplasms / Q000175:diagnosis / Q000188:drug therapy*; D016896:Treatment Outcome; D014467:Ultraviolet Therapy
chemical_list: D017319:Photosensitizing Agents; D000622:Aminolevulinic Acid