title: A randomized, multicentre study of directed daylight exposure times of 1½ vs. 2½ h in daylight-mediated photodynamic therapy with methyl aminolaevulinate in patients with multiple thin actinic keratoses of the face and scalp.
abstract: BACKGROUND
  Actinic keratoses (AKs) are common dysplastic skin lesions that may differentiate into invasive squamous cell carcinomas. Although a superior cosmetic outcome of photodynamic therapy (PDT) is advantageous compared with equally effective treatments such as cryotherapy and curettage, the inconvenience of clinic attendance and discomfort during therapy are significant drawbacks. Daylight-mediated PDT could potentially reduce these and may serve as an alternative to conventional PDT.
  
  
  OBJECTIVE
  To compare the efficacy of methyl aminolaevulinate (MAL)-PDT with 1½ vs. 2½ h of daylight exposure in a randomized multicentre study.
  
  
  METHODS
  One hundred and twenty patients with a total of 1572 thin AKs of the face and scalp were randomized to either 1½- or 2½-h exposure groups. After gentle lesion preparation and application of a sunscreen of sun protection factor 20, MAL was applied to the entire treatment area. Immediately after, patients left the clinic and exposed themselves to daylight according to the randomization. Daylight exposure was monitored with a wristwatch dosimeter and patients scored their pain sensation during treatment.
  
  
  RESULTS
  The mean lesion response rate at 3 months was 77% in the 1½-h group and 75% in the 2½-h group (P = 0·57). The mean duration of daylight exposure was 131 and 187 min in the two groups. The mean overall effective light dose was 9·4 J cm(-2) (range 0·2-28·3). Response rate was not associated with effective daylight dose, exposure duration, treatment centre, time of day or time of year during which the treatment was performed. Treatment was well tolerated, with a mean ± SD maximal pain score of 1·3 ± 1·5.
  
  
  CONCLUSIONS
  Daylight-mediated MAL-PDT is an effective, convenient and nearly pain-free treatment for patients with multiple thin AKs. Daylight-mediated PDT procedures were easily performed and 2 h of daylight exposure resulted in uniformly high response rates when conducted in the period from June to October in Nordic countries.
authors.affiliation: Department of Dermatology, University of Copenhagen, Bispebjerg Hospital, Bispebjerg Bakke 23, 2400 Copenhagen NV, Denmark. swie0001@bbh.regionh.dk
authors.forename: S R
authors.initials: SR
authors.lastname: Wiegell
authors.forename: S
authors.initials: S
authors.lastname: Fabricius
authors.forename: I M
authors.initials: IM
authors.lastname: Stender
authors.forename: B
authors.initials: B
authors.lastname: Berne
authors.forename: S
authors.initials: S
authors.lastname: Kroon
authors.forename: B L
authors.initials: BL
authors.lastname: Andersen
authors.forename: C
authors.initials: C
authors.lastname: Mørk
authors.forename: C
authors.initials: C
authors.lastname: Sandberg
authors.forename: G B E
authors.initials: GB
authors.lastname: Jemec
authors.forename: M
authors.initials: M
authors.lastname: Mogensen
authors.forename: K M
authors.initials: KM
authors.lastname: Brocks
authors.forename: P A
authors.initials: PA
authors.lastname: Philipsen
authors.forename: J
authors.initials: J
authors.lastname: Heydenreich
authors.forename: M
authors.initials: M
authors.lastname: Haedersdal
authors.forename: H C
authors.initials: HC
authors.lastname: Wulf
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000622:Aminolevulinic Acid / Q000031:analogs & derivatives* / Q000627:therapeutic use; D004307:Dose-Response Relationship, Radiation; D005148:Facial Dermatoses / Q000188:drug therapy*; D005260:Female; D006370:Heliotherapy / Q000379:methods*; D006801:Humans; D055623:Keratosis, Actinic / Q000188:drug therapy*; D008297:Male; D008875:Middle Aged; D017060:Patient Satisfaction; D017319:Photosensitizing Agents / Q000627:therapeutic use*; D012536:Scalp Dermatoses / Q000188:drug therapy*; D013997:Time Factors
chemical_list: D017319:Photosensitizing Agents; C475457:methyl 5-aminolevulinate; D000622:Aminolevulinic Acid