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A research study carried out at the
University of Dundee, Queen Mary University of London and the Wellcome Sanger Institute, identified azathioprine used for treating inflammatory bowel disease, arthritis, vasculitis and for preventing organ rejection in transplant patients can contributor to skin cancer.
The research identified a strong case for an association between the drug-azathioprine and the mutational signature found in cases of cutaneous squamous cell carcinoma (cSCC), a common form of skin cancer. The use of azathioprine leads to increased photosensitivity to UVA light, probably contributing to development of skin cancers.
According to Charlotte Proby, Professor of Dermatology in the School of Medicine at Dundee, we recommend all physicians give appropriate advice on UVA avoidance including year-round sun protection for their patients on azathioprine. As with all medications the risks must be balanced against the benefits.
Sun protection, skin surveillance and early lesion removal are part of the routine management of patients on azathioprine. cSCC is a common skin cancer. It’s good to protect the skin from the sun when taking medications which make the skin sun-sensitive. The most effective protection is to relax in the shade, cover up with a hat, long-sleeved top and sunglasses. Use sunscreen with at least 4 stars and SPF 15 or higher for protection against both UVA and UVB rays.
The researchers in the School of Medicine at Dundee, in collaboration with the Wellcome Sanger Institute and Queen Mary University of London, were able to carry out mutational signature analysis of cSCC tumours from 37 patients, many of whom had been on azathioprine. They found a new mutational signature, Signature 32, which correlated with time on azathioprine therapy.