Psoriasis associated with a higher cancer risk

A large, pooled population-based cohort study from Denmark, England, Israel, and Taiwan showed that psoriasis, especially severe disease, is linked to a higher cancer risk overall and in specific sites. In addition, psoriasis was associated with several cancers beyond those currently regarded as connected.

Mr Alex Trafford (University of Manchester, UK) noted that an association between cancer and psoriasis is plausible due to the chronic inflammation in psoriasis patients [1]. Moreover, lifestyle factors like smoking and alcohol consumption are particularly prevalent in patients with psoriasis. Yet, previous studies of cancer risk in people with psoriasis have yielded inconsistent results. To evaluate the possible relationship, Mr Trafford and colleagues aimed to investigate the risk of cancer occurrence in individuals with psoriasis by analysing data from population-based health records from Denmark, England, Israel, and Taiwan. They also wanted to explore whether cancer risk is associated with psoriasis severity. “As we had no direct data, we used systemic therapy as an indicator of moderate-to-severe psoriasis,” he explained.

Individuals with psoriasis from the cohort were matched with up to 6 individuals with no prior record of psoriasis based on a minimum of age, sex, and calendar time. Country-specific risks of cancer overall and site-specific cancers were analysed using Cox proportional hazards models. Patients who had cancer before were excluded from the analysis.

The analysis included 702,062 participants with psoriasis and 4,185,596 matched comparators. Age and sex were similar between countries. Patients in Denmark were older; in Taiwan, they were more likely to be men. In crude models, individuals with psoriasis (pooled HR 1.08; 95% CI 1.04–1.13) and the subgroup with moderate-to-severe psoriasis (pooled HR 1.16; 95% CI 1.04–1.28) had a slightly higher risk of cancer overall.

Further, people with psoriasis had higher risks for the following site-specific cancers: oral cavity, pharynx, oesophagus, liver, pancreas, kidney, bladder, skin (keratinocyte), Hodgkin lymphoma, non-Hodgkin lymphoma, and leukaemia. However, the risk elevation differed between cancer types, from a relatively modest 9% relative risk elevation in pancreas cancer to an almost doubled risk for Hodgkin lymphoma. “The cancer risk was exacerbated in more severe psoriasis. Moreover, additional associations for lung cancer and ovarian cancer were found in these patients,” Mr Trafford said.

In summary, the study established the associated increased risk of developing cancer in psoriasis patients. Associations generally persist, with a more pronounced risk, when limited to people with moderate-to-severe disease. The current study revealed that psoriasis is associated with several cancers, beyond those currently regarded to be linked to the condition. This should be recognised to guide optimal psoriasis care and future research.

 

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   1. Trafford AM, et al. Psoriasis and the risk of cancer development: pooled population-based cohort studies from Denmark, England, Israel and Taiwan. FC13, Psoriasis from Gene to Clinic 2021, 9–11 December.

 

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Posted on 2 February, 2022