Data from two large cohort studies did not show an association between atopic dermatitis (AD) and most cancers. However, the researchers observed an increased risk for noncutaneous lymphomas based on AD severity. The results of their studies were published in JAMA Dermatology.
Previous evidence on the association between AD and cancer has been unclear, the researchers said. They noted that it was also important to determine the baseline risk for cancers among patients with AD before exploring the potential association between new biologic therapies for AD and cancer risk.
In their study, the researchers used data from a large cohort study in England, which included 471,970 individuals with AD and 2,239,775 individuals without AD; as well as a large cohort study from Denmark, which included 44,945 individuals with AD and 445,673 individuals without AD. They compared overall cancer risk and risk of specific cancers between those with and those without AD.
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In both the English and Denmark cohorts, the researchers found little evidence of association between AD and overall cancer risk (adjusted hazard ratio [HR], 1.04; 99% CI, 1.02-1.06; and adjusted HR, 1.05; 99% CI, 0.95-1.16, respectively) or the risk for most specific cancers.
Notably, the researchers found an increased risk of noncutaneous lymphoma among individuals with AD in the English cohort (adjusted HR for non-Hodgkin lymphoma, 1.19; 99% CI, 1.07-1.34; and adjusted HR for Hodgkin lymphoma, 1.48; 99% CI, 1.07-2.04). Additionally, they observed an association between AD severity and lymphoma risk. Compared with individuals without AD, the adjusted HRs for non-Hodgkin lymphoma were 1.06 (99% CI, 0.90-1.25), 1.24 (99% CI, 1.04-1.48), and 2.08 (99% CI, 1.42-3.04) for mild, moderate, and severe AD, respectively.
The Danish point estimates also showed an increased lymphoma risk among people with moderate to severe AD compared with those without AD (minimally adjusted HR for non-Hodgkin lymphoma, 1.31; 99% CI, 0.76-2.26; and minimally adjusted HR for Hodgkin lymphoma, 1.35; 99% CI, 0.65-2.82). However, the 99% CIs were wide, the researchers noted.
“The findings from 2 large population-based studies performed in different settings do not support associations between AD and most cancers,” the researchers concluded. They added that the observed increased risk for lymphoma, particularly non-Hodgkin lymphoma, in association with disease severity warrants further study, as new immunomodulatory systemic therapies may alter cancer risk.
Mansfield KE, Schmidt SAJ, Darvalics B, et al. Association between atopic eczema and cancer in England and Denmark. JAMA Dermatol. Published online June 24, 2020. doi:10.1001/jamadermatol.2020.1948