Several studies have described increased risk ratios of certain types of malignancies in patients with severe psoriasis. Among these, the lymphoproliferative disorders, including non-Hodgkin’s lymphoma, cutaneous T-cell lymphoma and non-melanoma skin cancer, have been described most frequently. In addition to traditional cancer risk factors, some psoriasis treatments may also be implicated as potential carcinogens. The aim of this study was to perform a review of current literature on the association between psoriasis, the therapies against this disease and skin cancer, focusing on both epidemiology and the potential mechanism involved. Some psoriasis treatments, such as psoralen and ultraviolet A (PUVA) therapy and cyclosporine, have been associated with increased risk of skin cancer. Variable data have been reported for anti-tumour necrosis factor (TNF) drugs, whereas other class of biologics, like anti-IL17 and IL23, as well as ustekinumab, seem not to be related to skin cancer risk, such as the case of currently available small molecules.
