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Severe psoriasis increases risk for cancer-related mortality

An increase in overall cancer mortality risk was found in patients with severe psoriasis, and associations were identified within site-specific cancers such as colon and kidney among patients with all severities of psoriasis, according to a systematic review of 58 studies that was published in JAMA Dermatology.

“Cohort studies of all severities of psoriasis suggested a 1.18-fold increased risk of developing cancer compared with psoriasis-free populations,” Rosa Parisi, PhD, research associate in the School of Health Sciences at University of Manchester, U.K, and colleagues wrote. “Evidence from cohort studies of severe psoriasis indicated a 1.22-fold increased risk of developing cancer when compared with populations without psoriasis, a result not significantly different from that of all psoriasis severities.”

The researchers identified 58 studies using an electronic literature search. Fifty studies investigated the risk for cancer in psoriasis and 15 studies explored cancer mortality, with seven studies reporting on both.

The risk for all-cancer incidence in those with psoriasis was explored in 22 cohort studies. Among patients with severe psoriasis throughout nine studies, a pooled RR of 1.22 (95% CI, 1.08-1.39) was found with high heterogeneity (I² = 89.8%; 95% CI, 82.8-93.9).

Seven studies accounting for psoriasis of varying severities produced a significantly elevated pooled RR of 1.18 (95% CI, 1.06-1.31) with similarly higher heterogeneity (I² = 90.2%; 95% CI, 82.5- 94.6).

However, a hospital case-control study that reported on the cancer risk in psoriasis for all severities found a significantly reduced estimate, with an OR of 0.27 (95% CI, 0.16-0.44).

In site-specific cancer, researchers found a significantly elevated incident risk among patients with severe psoriasis for squamous cell carcinoma from three studies (RR = 11.74; 95% CI, 1.52-90.66); lymphoma in four studies (RR = 3.39; 95% CI, 1.34-8.62); basal cell carcinoma in three studies (RR = 3.17; 95% CI, 1.32-7.6); keratinocyte in seven studies (RR = 2.44; 95% CI, 1.68-3.56); esophagus in three studies (RR = 2.34; 95% CI, 1.14-4.8); liver in two studies (RR = 1.94; 95% CI, 1.51-2.49); pancreas in three studies (RR = 1.45; 95% CI, 1.15-1.83); and bladder in three studies (RR = 1.27; 95% CI, 1.06-1.52).

Moreover, for all severities of psoriasis, the incident risk was significantly elevated in 12 site-specific cancers including the oral cavity, squamous cell carcinoma, esophagus, liver, larynx, keratinocyte, kidney, pancreas, lymphoma, colorectum, non-Hodgkin lymphoma and colon.

In a meta-analysis of cancer mortality with patients with severe psoriasis, mortality risk was significantly elevated in the following sites: esophagus in two studies (RR = 2.53; 95% CI, 1.87-3.41); liver in two studies (RR = 1.43; 95% CI, 1.09-1.88); and pancreas in two studies (RR = 1.31; 95% CI, 1.02-1.69).

High levels of heterogeneity between some of the studies represent a study limitation, according to researchers. Within potential cofounders, how smoking, alcohol consumption and obesity are considered may present another possible limitation.

“Despite these findings, cancer currently receives relatively little focus in guidelines for the management of psoriasis, compared with other comorbidities, such as cardiovascular disease,” Parisi and colleagues wrote. – by Abigail Sutton

Disclosures: Parisi reports no relevant financial disclosure. Please see the study for all other authors’ relevant financial disclosures.