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Cancer Risk and Psoriasis

Patients with psoriasis had a slightly elevated risk for cancer, which was greater in those with more-severe and longer-enduring disease.

Many studies have shown an increased risk for leukemia, lymphoma, and cancers of the lung, liver, oropharynx, colon, kidney, breast, central nervous system, pancreas, genital organs, and thyroid in individuals with psoriasis. However, differences in design and inclusion criteria (e.g., of cigarette smokers) in these trials have produced varying results.

In a recent epidemiologic study, researchers examined cancer risk in 36,702 patients with psoriasis and 36,702 psoriasis-free matched controls. After exclusion of patients with histories of HIV or cancer, the psoriasis group had a subtly increased risk for lymphopoietic malignancies (incidence risk ratio, 1.81; confidence interval, 1.35–2.42) and digestive tract cancers (especially of the pancreas; IRR, 1.40; CI, 1.10–1.78). In a nested case-control analysis, psoriasis patients had an approximately twofold overall increase in relative risk for a lymphoproliferative malignancy, with the highest risk in recipients of oral treatments. Increased risk correlated with increased severity and duration of clinical psoriasis, and the increase persisted even when eight patients with cutaneous T-cell lymphoma were excluded.

Comment: A study of more than 35,000 psoriatic patients is, by my standards, a large study, and the data that it generates are, by my standards, reliable. The risk for certain cancers was increased, but not greatly. The risk was highest in psoriatic patients who had received oral therapy, but we don't know if oral therapy increased risk or reduced it. In other words, increased cancer risk was associated with severe disease (and therefore, frequently, with oral therapy), but the increase might have been even greater if the psoriasis had gone uncontrolled. I won't be doing extra cancer screening tests on my patients with psoriasis, nor scare them with results of this study.

— Mark V. Dahl, MD

Published in Journal Watch Dermatology November 20, 2009

Citation(s):

Brauchli YB et al. Psoriasis and risk of incident cancer: An inception cohort study with nested case-control analysis. J Invest Dermatol 2009 Nov; 129:2604.

• Medline abstract (Free)

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