Greater Atopic Dermatitis Severity May Increase Risk of Certain Cancers

A greater risk of lymphoma was identified in pediatric and adult patients with moderate to severe atopic dermatitis (AD), whereas risk of solid organ malignancy was shown to be reduced in these patient populations. Results were published in an abstract presented at the 2022 American Academy of Dermatology (AAD) Annual Meeting.

As a chronic disease with an approximate 20% lifetime prevalence, researchers noted AD has been associated with immunologic dysfunction that may influence cancer risk.

“AD may increase cancer risk due to chronic inflammation or immunologic defects inherent to AD and/or its treatment,” explained authors. “Conversely, increased immune surveillance due to overactive immune state in AD may also protect against cancer.”

Prior research reported in JAMA Dermatology that examined a patient cohort from England and Denmark indicated that AD was not significantly linked with most cancers. But an association was observed between the condition and lymphoma, particularly non-Hodgkin lymphoma, that increased with eczema severity.

Noting inconsistent results from prior epidemiologic studies that investigated cancer risk by disease severity, as well as a lack of research regarding pediatric populations with AD, the abstract authors conducted a population-based cohort study using the United Kingdom’s ​​The Health Improvement Network (THIN) database.

Participants were enrolled through February 2015 to assess the risk of malignancy, with the pediatric (age < 18 years at baseline) and adult (age ≥ 18) cohorts examined separately.

A total of 409,431 children and 625,083 adults with AD were matched on age, practice, and index date to 1,809,029 children and 2,678,888 adults without AD, respectively.

AD severity was estimated as mild, moderate, or severe using treatments as a proxy. Exclusion criteria included patients receiving systemic immunosuppressive medications for AD and those with comorbid asthma or allergic rhinitis.

Primary outcomes assessed were any malignancy (further categorized into hematologic, skin, and solid organ subgroups), with secondary outcomes of leukemia, lymphoma, melanoma, nonmelanoma skin cancer, and cancers of bladder, breast, colon, lung, pancreas, and prostate.

Overall, no significant association between AD and malignancy was found, but results varied by age, AD severity, and specific cancer type:

• Children with moderate and severe AD were at 71% and more than a 3-fold greater risk, respectively, of lymphoma compared with children without AD (moderate AD: HR, 1.71; 95% CI, 1.01-2.90; severe AD: HR, 3.13; 95% CI, 1.39-7.06; respectively)
• Risk of any incident malignancy did not differ by AD status in children overall (HR, 1.02; 95% CI, 0.92-1.12)
• Adults with moderate and severe AD were at 19% and more than a 2-fold greater risk, respectively, of lymphoma compared with children without AD (moderate AD: HR, 1.19; 95% CI, 1.10-1.30; severe AD: HR, 2.28; 95% CI, 1.92-2.71; respectively)
• Risk of any incident malignancy did not differ by AD status in adults overall (HR, 1.00; 95% CI, 0.99-1.02)
  

Furthermore, adults with severe AD were associated with a 15% greater risk of cancer compared with adults without AD (HR, 1.15; 95% CI, 1.10-1.20). Adults with moderate AD had a lower risk of solid organ malignancy (HR, 0.93; 95% CI, 0.92-0.95), including bladder, breast, colon, lung, and prostate cancer.

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

Reference

Wan J, Shin DB, Syed MN, Abuabara K, Lemeshow AR, Gelfand JM. Malignancy risk among children and adults with atopic dermatitis in a population-based cohort. Presented at: 2022 American Academy of Dermatology Annual Meeting. Abstract: 31772.