Slight rise in cancer risk seen with atopic dermatitis

A new study has found slightly increased risks of several types of cancer among patients with atopic dermatitis. But the findings should be interpreted with caution, the researchers caution, given their “borderline statistical significance,” the small number of patients with certain cancers, and other factors.

To investigate whether patients with atopic dermatitis might have an increased risk of skin and other types of cancer, Dr. Lena Hagstromer of the Karolinska Institute in Stockholm and her colleagues looked retrospectively at 15,666 patients hospitalized for atopic dermatitis from 1965 to 1999. The patients were linked to a number of national cancer registries including the National Swedish Cancer Register, and matched by age and sex to the general Swedish population. Average follow-up was 15.4 years.Overall, the team reports in the September issue of the Archives of Dermatology, atopic dermatitis patients were 13% more likely to develop cancer. They were 3.5 times more likely to develop esophageal cancer, and roughly twice as likely to develop brain or lung cancer or lymphoma. A similarly increased risk of pancreatic cancer was seen, but it was of borderline statistical significance. Men faced a 50% increased risk for non-melanoma skin cancer during the first 10 years of follow-up, which did not reach statistical significance.The higher rates of esophageal, lung and pancreatic cancer seen suggest that the results could be confounded by smoking and alcohol consumption, which the researchers were unable to control for. Also, atopic dermatitis patients are normally treated as outpatients, they add, so those hospitalized for atopic dermatitis treatment may have less healthy habits overall.Given that many people in the study were relatively young and that rates of most cancer types increase with age, “future follow-ups of our cohort would be interesting,” Dr. Hagstromer and colleagues conclude.(Source: Arch Dermatol 2005;141:1123-1127: Reuters Health: Oncolink: September 2005.)