According to a new study, the risk of melanoma developing in people with a history of atopic disease is up to 50% lower than in non-atopic people. Also, participants in the study with atopic disease demonstrated an even lower overall risk of skin cancer.
Published in Melanoma Research, the study is a collaboration between the North Savo Skin Cancer Programme, the University of Eastern Finland, and Kuopio University Hospital. It included 496 adult subjects (age range 21 to 79 years, 250 males, 246 females, 94 with immunosuppression) at an increased risk of skin cancer (basal cell carcinoma, squamous cell carcinoma, or melanoma).
In the study, the patients’ history of atopic disease was assessed, their skin was examined clinically, and then the patients were classified into low risk, moderate risk, or high skin cancer risk groups. Patients with atopic disease were also divided into groups based on whether they had mucous membrane atopy or atopic dermatitis.
In the group of 171 atopic patients, the researchers reported fewer cases of melanoma (14.6%) than in 325 non-atopic patients (22.2%) (p=0.044), fewer cancers in extracutaneous sites, and a better general skin cancer risk classification than in the non-atopic group. Logistic regression analysis showed the risk of melanoma in atopic patients was almost 50% lower, and the risk of cancers in extracutaneous sites was more than 50% lower than in non-atopic patients.
The researchers note that when 94 immunosuppressed patients were excluded from the analysis, the reduced melanoma risk was particularly pronounced in the mucous membrane atopy group—the risk was more than 50% lower than in the non-atopic group.
The authors note the prevalence of atopic diseases has increased in industrialized countries, as has the prevalence of skin cancers. Some studies have indicated that chronic inflammation associated with atopic diseases, or an abnormal immune response, may either contribute to the development of cancer, or prevent it.
“The latest theory is that the skin has a naturally occurring autoreactive immunoglobulin E response that could protect against carcinogens and skin damage leading to cancer,” said Professor Ilkka Harvima, who led the study at the University of Eastern Finland and Kuopio University Hospital, in a press release. “This theory makes sense because atopic diseases typically involve an IgE-mediated allergy, so the protective mechanism may be even more pronounced in atopic skin.”