Adult-onset cancer survivors, especially those with hematologic malignancies, have an increased rate of comorbid psoriasis, researchers reported in a study published in the British Journal of Dermatology.
The investigators conducted a nationwide, population-based cohort study to determine the incidence of psoriasis among survivors of adult-onset cancer. Data were obtained from the Korean National Health Insurance Service (NHIS) database and included patients aged 50 years or older who had undergone cancer screening. Patients who had a history of psoriasis were excluded.
A total of 804,836 newly enrolled cancer survivors from 2009 to 2015 were compared with 1,613,046 age- and sex-matched cancer-free individuals. The number of patients with newly diagnosed psoriasis until December 2017 was the primary endpoint.
Cancer-free control participants had a psoriasis incidence rate per 1000 person-years of 3.46, and cancer survivors had an incidence rate per 1000 person-years of 4.76. Multivariate Cox proportional hazard model analysis showed that cancer survivors had a significantly increased risk for psoriasis (hazard ratio [HR], 1.41; 95% CI, 1.38-1.43) compared with control participants without cancer after adjustment for age, sex, and comorbidities.
Higher risks for psoriasis were observed in cancer survivors of leukemia (HR, 3.36), lymphoma (HR, 2.66), multiple myeloma (HR, 2.50), skin cancer (HR, 2.32), and lung cancer (HR, 2.02) compared with cancer-free control participants. Survivors of uterine and testicular cancer did not have a significantly elevated risk after adjustment for potential confounders.
“It is conceivable that the chronic inflammatory nature of cancer, as well as commonly associated risk factors such as obesity, smoking, and alcohol consumption, may increase the risk of psoriasis among cancer survivors,” commented the researchers. “In addition, cancer may potentially predispose patients to the development of psoriasis. In other words, cancer cells per se or immunosuppressive cancer therapies (including chemotherapy and radiotherapy) may affect the immune systems of cancer patients.”
Study limitations include the fact that only the ICD-10 code was used to identify patients. Also, detailed information was lacking in individual patients, and there is a high risk that the findings are owing to surveillance bias.
“The relative contributions of initial misdiagnosis and possible effects of systemic medication on the immune system need further study,” stated the investigators.
Kim M, Park HE, Han K, Lee J. Risk of psoriasis among survivors of adult-onset cancer: a nationwide population-based cohort study. Br J Dermatol. Published online June 30, 2021. doi:10.1111/bjd.20610