MedWire News: People with psoriasis may face a higher-than-expected risk of developing certain cancers, research suggests.

The study found that the incidence of lymphohematopoietic and pancreatic tumours was increased in patients with psoriasis, particularly those with longer-term and more severe disease. However, the study authors warn that the associations need to be confirmed in future prospective studies.

The research, by Christopher Meier (University Hospital Basel, Switzerland) and colleagues, was a nested case–control analysis of an observational dataset, the UK General Practice Research Database. The study population consisted of 36,670 patients with psoriasis and 34,001 psoriasis-free patients matched for age and gender.

The average duration of follow-up was 4.6 years, during which time 1703 patients were diagnosed with cancer. The incidence rate was 5.83 per 1000 person-years in patients with psoriasis and 5.18 per 1000 person-years in those without psoriasis.

More detailed analysis revealed that the risk of developing lymphohematopoietic malignancies (including leukaemia and lymphoma) and pancreatic cancer was significantly higher in patients with psoriasis. This was not the case for other types of cancer.

The study also identified positive associations between the severity of psoriasis (as indicated by use of systemic therapy) and the duration of psoriasis and increased cancer risk.

Meier et al conclude that their large, population-based study provides evidence of an association between psoriasis and specific cancers, which increases with disease duration.

“Further investigation into common mechanisms underlying psoriasis and the cancers identified in this study is warranted,” they write.

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