From the Journals

Psoriasis elevates cancer risk



Psoriasis patients are at increased risk for several types of cancer, notably lymphoma and keratinocyte cancer, based on data from a systematic review and meta-analysis of more than 2 million patients.

Previous studies have identified an increased overall cancer risk in psoriasis patients, compared with the general population or controls without psoriasis, and both lymphomas and keratinocyte cancers occur more often in psoriasis patients, compared with controls, but additional larger studies have been conducted since the last meta-analysis was published in 2013, wrote Sofie Vaengebjerg, MD, of the University of Copenhagen and colleagues.

To better identify the risk of cancer in psoriasis and psoriatic arthritis patients and to explore the impact of biologics, the researchers reviewed data from 112 studies totaling 2,053,932 patients in a study published in JAMA Dermatology.

Overall, the risk of any cancer was slightly higher in psoriasis patients (risk ratio, 1.21; 95% confidence interval, 1.11-1.33), compared with controls, with a prevalence of 4.78% and an incidence rate of 11.75 per 1,000 person-years. The most common cancer among psoriasis patients was keratinocyte cancer, with a risk ratio of 2.28 (95% CI, 1.73-3.01), a prevalence of 2.55%, and an incidence rate of 4.35 per 1,000 person-years.

Other cancers with significantly elevated risk among psoriasis patients were lymphomas (RR, 1.56; 95% CI, 1.37-1.78), lung cancer (RR, 1.26; 95% CI, 1.13-1.40), and bladder cancer (RR, 1.12; 95% CI, 1.04-1.19).

No increased risk of cancer was noted among psoriasis patients who were treated with biologics. “However, patients receiving biologic agents are selected and the results might be reliant on selection bias, and studies investigating long-term safety of these drugs are still limited,” the researchers wrote.

In addition, psoriatic arthritis was not associated with any overall increase in cancer risk, with the exception of three studies showing an increased risk for breast cancer, the researchers noted. The overall cancer prevalence for psoriatic arthritis patients was 5.74%, with an incidence rate of 6.44 per 1,000 person-years.

The study findings were limited by several factors, including the inconsistencies in study design and characteristics and the small amount of data on biologic agents and psoriatic arthritis, the researchers noted. However, the results were strengthened by the large number of patients, real-world study settings, inclusion of biologics, and analysis of cancer in psoriatic arthritis patients.

“Clinicians treating patients with psoriasis should be aware of this increased risk, especially for lymphomas, as immunogenic treatment might be associated with exacerbations,” and should be aware that more research is needed to assess cancer risk associated with biologics, they concluded.

The study received no outside funding. Lead author Dr. Vaengebjerg had no financial conflicts to disclose. Several coauthors disclosed relationships with multiple companies, including AbbVie, Janssen, Novartis, Eli Lilly, LEO Pharma, UCB, Almirall, and Sanofi.

SOURCE: Vaengebjerg S et al. JAMA Dermatol. 2020 Feb 19. doi:10.1001/jamadermatol.2020.0024.

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