Atopic dermatitis, naevi count and skin cancer risk: A meta-analysis

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 >= 2 mm 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, I-2=85%). We found a significantly increased risk of basal cell cancer (BCC) (SRR= 1.34, 95%CI 1.03-1.75, I-2=24.0%) but not for squamous cell cancer (SRR= 1.91, 95% CI 0.74-4.91, I-2= 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. (C) 2016 Japanese Society for Investigative Dermatology. Published by Elsevier Ireland Ltd. All rights reserved.