Research Suggests Screening for Malignancies in Patients with Psoriasis

Tomoya Watanabe, Yokohama City Univerity

Investigators led by Tomoya Watanabe, Department of Environmental Immuno-Dermatology, Yokohama City University School of Medicine, aimed to better determine the association between psoriasis and malignancy onset. While many investigations have indicated patients with psoriasis are at an increased risk of malignancies, an association has yet to be established.

The systemic, chronic, immunologically-mediated disease is estimated to affect 2%-4% of the worldwide population. Psoriasis is also known to be associated with multiple other comorbidites including metabolic syndrome, cardiovascular disease, and depression.

According to the team of investigators, previous studies have shown psoriasis may progress from a complex relationship between genetic disposition, environmental triggers, and immune dysfunction. Inflammatory diseases like psoriasis, as well as lupus erythematosus and rheumatoid arthritis, can lead to systemic chronic inflammation followed by other complications.

Analyzing Psoriasis Associations

The study consisted of a retrospective analysis that included 360 patients with psoriasis with the objective of identifying incidence of malignancies as well as any varying types of malignancies present in these patients.

In addition to collecting age, sex, body weight, height, body mass index (BMI), and medical history, investigators gathered patients' psoriasis data (comorbidities, laboratory data, age at onset of psoriasis, treatment history and type of psoriasis), as well as malignancy data (age at malignancy onset, type of malignancy, smoking history, and treatment outcomes).

Results show continuous variables in terms of mean and standard deviation. The team used Fisher's exact test and Mann–Whitney U test for the statistical analyses. The standardized incidence difference and ratio (SID, SIR) were used to compare the incidence of cancer in patients with psoriasis and healthy populations according to Cancer Statistics 2016 and 2017 by the National Cancer Registry.

Identifying Risk of Malignancy

Results revealed a 14.4% incidence rate of malignancy, or 52 of the 360 patients. The highest association with malignancy was colorectal cancer (20.9%). Other prominent associations included skin cancer (16.4%), gastric cancer (10.4%), and lung cancer (10.4%).

According to the team, data indicated that the malignancy rate was higher in patients with psoriasis than in the general population, however the difference did not exhibit statistical significance. Additionally, males displayed an increased risk of malignancy.

"We also observed that treatment with biological agents tends to reduce the risk of developing malignancy; however, no statistical significance was found," investigators wrote. "These results suggest that periodic screening for malignancy should be recommended in patients with psoriasis having these risk factors and in those with poorly controlled psoriatic inflammation."

The study "Risks of malignancies among patients with psoriasis: A cohort study of 360 patients" was published in Japanese Dermatological Association.