Psoriasis therapy and the risk of skin cancers

Photochemotherapy (PUVA) and methotrexate (MTX) are treatments frequently prescribed in patients with severe psoriasis. However, both treatments have carcinogenic potential. A group of 227 patients, who had been treated with PUVA, MTX or the combination, was investigated for the presence of cancer of the skin. As a control, the partners of these patients were investigated at the same visit. Cancers of the skin were observed in 15 out of 227 psoriatics, compared to one out of 95 control subjects. In the psoriatic patients a previous history of skin cancer, arsenic intake and X-ray treatment were observed more frequently. The increased frequency of skin cancers in psoriatics treated with PUVA, MTX and the combination of both, justifies regular surveillance on skin cancer in these patients.