Patients with psoriasis are at increased risk of certain cancers and there are questions about the contribution of long-term use of biologic and immune modulatory therapies to the risk factors. A roundtable was convened to look at questions around the association between cancer and psoriasis and to make clinical observations and recommendations based on published literature and expert opinion.
Some observations about cancer risk include the following:
• Chronic inflammation, such as is seen with psoriasis, is associated with an increased risk of cancer; however, it is difficult to separate out confounding comorbidities, particularly smoking, alcohol, diabetes and obesity, which all independently increase the risk of cancer.
• Patients with psoriasis have a slight increase in the relative risk of developing solid organ malignancies. This risk increases with the severity of psoriasis, but again, increased risk is strongly associated with comorbid risk factors.
• Patients with psoriasis are also at greater risk for developing hematological cancers (such as lymphoma) but the absolute risk remains very low.
• The risk of squamous cell carcinoma is increased in psoriasis, but melanoma risk may be lower.
Regarding the use of biologic or systemic immune therapies and their relation to cancer risk, the authors note that:
• PUVA (>200 treatments) and/or >6 months continuous cyclosporine significantly increase the risk of squamous cell carcinoma in patients with psoriasis.
• Immune modulatory treatment has minimal, if any, significant additional effect on the risk of developing either solid cancers or lymphoma in patients with psoriasis.
• Managing immune response from psoriasis earlier may help reduce risk.
The authors conclude that an important reminder is that reducing common risk factors such as obesity, smoking and alcohol consumption is more critical for reducing cancer burden than stopping or avoiding a systemic immune modulatory agent.