title: A retrospective study of the effect of long-term topical application of retinaldehyde (0.05%) on the development of actinic keratosis.
abstract: BACKGROUND
  The role of topical retinoids on photocarcinogenesis is still unclear. Retinaldehyde is a natural metabolite of vitamin A used as a cosmetic product. Its effect on actinic keratoses has not been studied to date.
  
  
  OBJECTIVE
  To study the incidence of actinic keratoses during long-term application of retinaldehyde in order to evaluate a possible chemoprophylactic effect.
  
  
  METHODS
  We conducted a retrospective study on 61 patients who had applied retinaldehyde on photoexposed body areas for a period ranging from 6 to 142 months. We counted the total number of actinic keratoses and cutaneous tumors that appeared over the time of exposure to retinaldehyde.
  
  
  RESULTS
  The epidemiological characteristics of actinic keratoses were not modified by the application of retinaldehyde. Irregular application as compared to regular application of retinaldehyde was not associated with a change in the risk of actinic keratoses, suggesting that continuous use is not associated per se with a higher risk of actinic keratoses.
  
  
  CONCLUSIONS
  With the statistical power limitation of this study, retinaldehyde applied alone does not appear to have prophylactic effects on the development of actinic keratoses. The design adopted is feasible to study the safety of cosmetic products applied for a long period of time.
authors.affiliation: Department of Dermatology, University Hospital, Geneva, Switzerland. campanelli@infomaniak.ch
authors.forename: Alexandre
authors.initials: A
authors.lastname: Campanelli
authors.forename: Luigi
authors.initials: L
authors.lastname: Naldi
mesh_terms: D000287:Administration, Topical; D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D018890:Chemoprevention; D005260:Female; D006801:Humans; D007642:Keratosis / Q000209:etiology / Q000517:prevention & control*; D008297:Male; D008875:Middle Aged; D009381:Neoplasms, Radiation-Induced / Q000517:prevention & control; D012172:Retinaldehyde / Q000008:administration & dosage* / Q000009:adverse effects; D012189:Retrospective Studies; D012878:Skin Neoplasms / Q000517:prevention & control; D013472:Sunlight / Q000009:adverse effects
chemical_list: D012172:Retinaldehyde