Eczema linked to keratinocyte carcinoma, kidney cancer

Observational evidence identified a potential association between atopic dermatitis and an increased risk for keratinocyte carcinoma and kidney cancer, as well as lower odds of lung and respiratory system cancers, according to a meta-analysis in JAMA Dermatology.

Eight population-based studies were included in the systematic review with 5,726,692 participants from the U.K., Sweden, Taiwan and Denmark. Forty-eight case-control studies were also included, with 114,136 participants. Study timelines ranged from 1956 to 2014 and the mean age of participants was 3 to 69 years.

Among the cohort studies without substantial heterogeneity, researchers found statistically significant associations between AD and a higher incidence of keratinocyte carcinoma in five studies (standardized incidence ratio [SIR] = 1.46; 95% CI, 1.2-1.77) in addition to cancers of the kidney in two studies (SIR = 1.86; 95% CI, 1.14-3.04), central nervous system in two studies (SIR = 1.81; 95% CI, 1.22-2.7) and pancreas in one study (SIR = 1.9; 95% CI, 1.03-3.5).

Among the case-control studies without heterogeneity, AD was associated with significantly lower odds of central nervous system cancers in 15 studies (OR = 0.76; 95% CI, 0.7-0.82) and pancreatic cancer in five studies (OR = 0.81; 95% CI, 0.66-0.98), in contrast to the higher incidence found in cohort studies. Researchers also identified a significantly lower odds of lung and respiratory system cancers in four studies (OR = 0.61; 95% CI, 0.45-0.82).

There was no evidence of a relationship between AD and other cancer types among breast, colorectal, head and neck, male genitourinary, myeloma and melanoma, according to researchers.

Among the studies, researchers discovered substantial heterogeneity for many types of cancer, precluding meta-analysis. Cohort studies on leukemia and lymphomas, melanomas, female and male genitourinary, gastrointestinal, lung and respiratory system cancers had high heterogeneity. Three of the eight cohort studies had a serious risk of bias and five had a moderate risk of bias.

Surveillance may increase skin cancer detection among patients with AD due to frequent follow-up. The associated loss of function of the filaggrin gene, OMIM 135940, in some patients with AD may also contribute to pathogenesis, according to researchers.

“Given the statistically significant heterogeneity of outcomes and the substantial risk of bias among included studies, further research with clearly defined criteria for AD diagnosis, adjustment for key confounders and details on AD severity and treatment is required to better understand the mechanisms underlying the possible association between AD and cancer risk,” Rachel Bierbrier, MD, of the division of dermatology at McGill University Health Centre in Montreal, and colleagues wrote. – by Abigail Sutton

Disclosures: Bierbrier reports no relevant financial disclosures. Please see the study for all other authors’ relevant financial disclosures.