A study from the University of Eastern Finland found fewer cases of melanoma and skin cancer in people with a history of atopy.
Atopy refers to atopic diseases, such as asthma or rhinitis. According to the researchers, the risk of melanoma was 50% lower in people with atopy compared to a control group. They also found that people with atopy had a significantly lower risk of cancer and that cancer in extracutaneous sites was less prevalent in people with atopy.
The study, which assessed the risk of cancer in nearly 500 people, was completed in collaboration with Kuopio University Hospital. The paper, ‘Patients with a history of atopy have fewer cutaneous melanomas than those without atopy: a cross-sectional study in 496 patients at risk of skin cancers’, has been published in Melanoma Research.
Atopy cases have risen in recent years
Atopic diseases have become more prevalent in industrialised countries over recent decades. Rates of skin cancers have also risen, causing researchers to question a possible association between the two.
Previous research on the link between atopy and skin cancer has provided inconclusive results. Studies have suggested that chronic inflammation and abnormal immune responses can aid the development of cancers 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. This theory makes sense because atopic diseases typically involve an IgE-mediated allergy so that the protective mechanism may be even more pronounced in atopic skin,” explained Professor Ilkka Harvima, who led the study.
The researchers examined patients from the dermatological outpatient clinic of Kuopio University Hospital, who were estimated to have an increased risk of skin cancers such as basal cell carcinoma, squamous cell carcinoma and melanoma.
A team of dermatologists from the University of Eastern Finland then analysed each patient’s medical history and examined their skin. Patients were then divided into three subgroups based on their skin cancer risk: low risk, moderate risk, and high risk.
Patients were divided into separate classifications based on their history of atopic diseases and whether they had mucous membrane atopy or atopic dermatitis.
The relationship between atopic diseases and cancer risk
The study revealed that there were significantly fewer cases of melanoma and cancers in extracutaneous sites in the group containing 171 atopic patients. The same group also had better general skin cancer risk classification than the nonatopic group. According to the researchers, the risk of melanoma was 50% lower in atopic patients, and the risk of cancer in extracutaneous sites was 50% lower in nonatopic patients.
When the researchers removed 94 immunosuppressed patients from their analysis, they found that the reduced melanoma risk was even more pronounced in the mucous membrane atopy group. This risk in this group was 50% lower than in the nonatopic group.
The researchers found no significant association between atopy and the severity of photoaging, actinic nevus count, keratoses, and basal and squamous cell carcinoma. As well as this, no association was found between Serum total IgE levels and skin changes or cancers in extracutaneous sites. The researchers were limited by the cross-sectional nature of the study and were, therefore, unable to prove a causal link.
“The cellular mechanism between atopy and melanoma needs to be studied further, and skin biopsies taken from the study subjects are currently under analysis,” concluded doctoral researcher and first author of the study, Jenni Komulainen.