according to a meta-analysis of cohort and case-control studies.
Compared with a psoriasis-free population, having a diagnosis of severe psoriasis was associated with a 22% increase in cancer risk, Alex Trafford of the University of Manchester (England) and colleagues reported in. The risk of cancer mortality was also increased by 22% among those with severe psoriasis.
The site-specific risks ranged from a low of 18% for colon cancer to more than a twofold increased risk for oral and esophageal cancer, according to the investigators.
Since these were associations only, any underlying mechanism is still unclear, they wrote. The chronic inflammation that drives psoriasis can also drive the development of cancer, but immunomodulatory therapies may also play a part, they suggested.
“Of particular relevance in this regard are biological therapies, which are being increasingly used for the management of psoriasis,” they added. “Although preliminary studies have suggested little to no increased risk of cancer incidence in patients with psoriasis receiving these therapies, further study allowing greater follow-up and increased power is required to properly examine the potential cancer risk, particularly for site-specific cancers.”
The analysis included 58 studies, published between 1983 and 2017. Nine of these reported risks for cancer incidence among patients with severe psoriasis, and seven reported the risk of cancer mortality among patients with all severities of psoriasis.
Overall, severe psoriasis was associated with an increased cancer risk of 22%; for all severities of psoriasis combined, the risk increase was 18%. Relative risks for specific cancer types were as follows: colon, 1.18; colorectal, 1.34; kidney, 1.58; laryngeal, 1.79; liver, 1.83; lymphoma, 1.40; non-Hodgkin lymphoma, 1.28; keratinocyte cancers, 1.71; esophageal 2.05; oral cavity, 2.80; and pancreatic, 1.41.
Overall cancer mortality risk was 22% higher in patients with severe psoriasis than the general population. Site-specific relative mortality risks included liver, 1.43; esophageal 2.53; and pancreatic, 1.31.
In light of these findings, clinicians should stress lifestyle modifications known to decrease cancer risk, the investigators said. “Although it has been noted that lifestyle behavior change is challenging for healthcare professionals to implement, the importance of a more holistic approach to psoriasis care involving lifestyle behavior change is reinforced through the results of this meta-analysis.”
Among the coauthors were
SOURCE: Trafford A et al. JAMA Dermatol. 2019 Oct 16. .