Atopic Dermatitis Linked to Increased Risk of Select Cancers

Joy Wan, MD, MSCE

Atopic dermatitis was associated with increased risk of select cancers – lymphoma in particular – and potentially lower risk of solid malignancies.

The new findings, presented at the American Academy of Dermatology (AAD) 2022 Annual Meeting in Boston, MA, detailed the associations made regarding the skin disease and risk of cancer development.

The increased risk of cancer development has been suggested due to chronic inflammation or immunologic defects inherent to both atopic dermatitis and treatment for the disease.

However, increased immune surveillance due to an overactive immune state in atopic dermatitis may also protect patients against cancer. As such, inconsistent findings across a variety of cancer subtypes and study designs exist.

Joy Wan, MD, MSCE, Department of Dermatology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, examined the risk of malignancy in a population-based cohort of children and adults with atopic dermatitis.

Wan and colleagues recruited patients from The Health Improvement Network (THIN) database through February 2015, and examined pediatric and adult patients separately.

Inclusion criteria involved 1 of 5 common Read diagnostic codes for atopic dermatitis and 2 therapy codes related to the disease and the severity of atopic dermatitis having been estimated using treatments as proxy.

Each patients with atopic dermatitis was matched to up to 5 unexposed controls on age, practice, and encounter within 6 months of the index date for atopic dermatitis.

The primary outcome of the study was the identification of any malignancy in affected patients, while secondary outcomes included leukemia, lymphoma, melanoma, non-melanoma skin cancer, and cancers of the bladder, breast, colon, lung, pancreas, and prostate.

Overall, Wan and investigators found no significant association between atopic dermatitis and malignany. However, results varied by age, severity, and specific skin cancer type.

Adults with severe atopic dermatitis had 15% greater risk of cancer overall compared to controls, while moderate to severe atopic dermatitis was associated with a 71-313% and 19-228% greater risk of lymphoma in children and adults, respectively.

Additionally, adults with moderate atopic dermatitis has a slightly lower risk of solid organ malignancy that included bladder, breast, colon, lung, and prostate cancers.

Wan and colleagues noted several potential limitations of their study, including the duration of follow-up and misclassification of disease severity. Most notably, they cited an inability to disentangle effects of disease severity from treatment.

“As immunomodulatory therapies continue to emerge for AD, this heterogeneous relationship between AD and malignancy requires continued investigation,” the team said.