title: Atopic dermatitis, naevi count and skin cancer risk: A meta-analysis.
abstract: BACKGROUND
  The risk of skin malignancy among atopic dermatitis (AD) patients is not well established.
  
  
  OBJECTIVE
  We reviewed the epidemiological evidence on the association between AD, naevi count, and the risk of cutaneous melanoma and keratinocyte skin cancer (KSC).
  
  
  METHODS
  We included all studies that compared the naevi count and the risk of skin cancer (melanoma and/or KSC) between AD patients and unaffected individuals. We calculated summary relative risks (SRRs) and 95% confidence intervals (CI) through random effects models; explored correlates of between-studies heterogeneity using sub-group and sensitivity analysis; and assessed publication bias using a funnel-plot-based approach.
  
  
  RESULTS
  The number of common naevi larger ≥2mm on the whole body was consistently lower among AD patients vs. unaffected individuals when measured by trained health professionals. The risk of melanoma was not increased among AD patients (SRR=0.77, 95%CI 0.44-1.35, I2=85%). We found a significantly increased risk of basal cell cancer (BCC) (SRR=1.34, 95%CI 1.03-1.75, I2=24.0%) but not for squamous cell cancer (SRR=1.91, 95% CI 0.74-4.91, I2=0.0%); however, only a few papers adjusted for phenotypic characteristics and/or sunlight exposure. We found no evidence of publication bias.
  
  
  CONCLUSIONS
  AD patients may be at increased BCC risk; however, methodological limitations prevented from drawing definitive conclusions. Despite the lack of strong scientific evidence, AD patients should avoid excessive sun exposure, regularly perform skin self examination, and consult a doctor in case of a suspicious skin lesion.
authors.affiliation: Division of Epidemiology and Biostatistics, European Institute of Oncology, Milan, Italy. Electronic address: sara.gandini@ieo.it.
authors.forename: Sara
authors.initials: S
authors.lastname: Gandini
authors.affiliation: Skin Cancer Unit, IRCCS-IRST Scientific Institute of Romagna for the Study and Treatment of Cancer, Meldola, Italy. Electronic address: igstanga@tin.it.
authors.forename: Ignazio
authors.initials: I
authors.lastname: Stanganelli
authors.affiliation: Cancer Risk Factors and Lifestyle Epidemiology, Cancer Research and Prevention Institute (ISPO), Florence, Italy. Electronic address: d.palli@ispo.toscana.it.
authors.forename: Domenico
authors.initials: D
authors.lastname: Palli
authors.affiliation: Department of Dermatology, University of Florence, Florence, Italy. Electronic address: vincenzo.degiorgi@unifi.it.
authors.forename: Vincenzo
authors.initials: V
authors.lastname: De Giorgi
authors.affiliation: Cancer Risk Factors and Lifestyle Epidemiology, Cancer Research and Prevention Institute (ISPO), Florence, Italy. Electronic address: g.masala@ispo.toscana.it.
authors.forename: Giovanna
authors.initials: G
authors.lastname: Masala
authors.affiliation: Cancer Risk Factors and Lifestyle Epidemiology, Cancer Research and Prevention Institute (ISPO), Florence, Italy. Electronic address: s.caini@ispo.toscana.it.
authors.forename: Saverio
authors.initials: S
authors.lastname: Caini
mesh_terms: D000293:Adolescent; D000328:Adult; D002280:Basal Cell Carcinoma / Q000453:epidemiology*; D002648:Child; D002675:Child, Preschool; D003876:Dermatitis, Atopic / Q000453:epidemiology*; D005260:Female; D006801:Humans; D015603:Keratinocytes / Q000166:cytology; D008297:Male; D008545:Melanoma / Q000453:epidemiology*; D008875:Middle Aged; D009506:Nevus / Q000453:epidemiology*; D010641:Phenotype; D012307:Risk Factors; D012878:Skin Neoplasms / Q000453:epidemiology*; D055815:Young Adult
keywords: Atopic dermatitis; Cutaneous melanoma; Keratinocyte skin cancer; Meta-analysis; Naevi count