title: Low-dose retinoids in the prevention of cutaneous squamous cell carcinomas in organ transplant recipients: a 16-year retrospective study.
abstract: OBJECTIVE
  To evaluate the long-term efficacy of systemic retinoids in reducing the incidence of cutaneous squamous cell carcinomas (SCCs) in organ transplant recipients (OTRs), who are at greatly increased risk of SCCs.
  
  
  METHODS
  A retrospective before-after study of OTRs who had received low-dose systemic retinoids during 1 to 16 years for prevention of SCCs.
  
  
  METHODS
  A specialist dermatology clinic for organ transplant recipients at St Bartholomew's and the Royal London Hospital, University of London, London, England.
  
  
  METHODS
  Thirty-two OTRs with at least 1 histologically proved SCC.
  
  
  METHODS
  Continuous systemic retinoids at dosages of 0.2 to 0.4 mg/kg per day for a minimum of 12 months.
  
  
  METHODS
  The mean difference between the number of SCCs developing annually during retinoid treatment and the number during the 12-month pretreatment interval.
  
  
  RESULTS
  In 28 continuously treated individuals, the mean number of SCCs in the 12-month pretreatment interval was 2.9. The number of SCCs was significantly reduced, with a mean difference of 1.46 in the first year of treatment (P = .006), 2.20 in the second (P<.001), and 2.14 in the third (P = .02). The numbers of SCCs were also reduced in subsequent years, but this effect was no longer significant because of smaller patient numbers. Six patients in whom retinoid treatment was interrupted subsequently had a significant increase in SCCs.
  
  
  CONCLUSIONS
  Low-dose systemic retinoids significantly reduce SCC development in OTRs for the first 3 years of treatment, and this effect may be sustained for at least 8 years, with a generally well-tolerated side-effect profile. Studies are now required to further optimize their use as a chemopreventive strategy in high-risk OTRs.
authors.affiliation: Centre for Cutaneous Research, St Bartholomew's and the Royal London School of Medicine and Dentistry, Queen Mary, University of London, London, England. caharwood@doctors.org.uk
authors.forename: Catherine A
authors.initials: CA
authors.lastname: Harwood
authors.forename: Mary
authors.initials: M
authors.lastname: Leedham-Green
authors.forename: Irene M
authors.initials: IM
authors.lastname: Leigh
authors.forename: Charlotte M
authors.initials: CM
authors.lastname: Proby
mesh_terms: D000328:Adult; D000368:Aged; D002294:Carcinoma, Squamous Cell / Q000453:epidemiology / Q000517:prevention & control*; D015331:Cohort Studies; D016001:Confidence Intervals; D004305:Dose-Response Relationship, Drug; D004334:Drug Administration Schedule; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D016377:Organ Transplantation / Q000009:adverse effects* / Q000379:methods; D011322:Primary Prevention / Q000379:methods; D011336:Probability; D012176:Retinoids / Q000627:therapeutic use*; D012189:Retrospective Studies; D018570:Risk Assessment; D012878:Skin Neoplasms / Q000453:epidemiology / Q000517:prevention & control*
chemical_list: D012176:Retinoids