Cancer Risk May be Higher in Korean Patients With Than Without Psoriatic Arthritis

In Korea, patients with psoriatic arthritis (PsA) have an increased risk of cancer compared with the general population, particularly non-melanoma skin cancer, lymphoma, and thyroid cancer, according to a study published in RMD open.¹

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“Our study suggests the need to pay attention to cancer screening by a detailed history and comprehensive clinical examination in patients with psoriatic arthritis,” wrote Yeonghee Eun, MD, PhD, Kangbuk Samsung Hospital, Sungkyunkwan University School of Medicine in Seoul, South Korea, and colleagues.

While psoriasis is associated with an increased risk of cancer, there is little data on the association between PsA and cancer risk. Additionally, evidence is scarce in Asian populations as most studies have been conducted in Western countries. Therefore, the researchers aimed to compare the cancer incidence in patients with PsA with that of the general population in a nationwide population-based cohort in South Korea.

Using data from the Health Insurance Review and Assessment Service (HIRA) database, 4688 patients newly diagnosed with PsA between January 1, 2010 and June 30, 2021 were included in this retrospective study, along with 46,88 age-matched and sex-matched controls. The participants’ mean age was 49 years and 57% were men. Comorbidities such as diabetes and hypertension were more common in patients with PsA. The primary outcome was the incidence of cancer and the secondary outcome was the incidence of specific cancer types. Participants were followed up from the index date until the occurrence of cancer, death, or the end of the study, whichever occurred first.

A total of 162 cancers occurred in the patients with PsA (incidence rate 83.2 [95% confidence interval (CI) 70.8 to 97.0] per 10,000 person-years) and 1307 cancers occurred in the controls (incidence rate 66.9 [95% CI 63.3 to 70.6] per 10,000 person-years). The adjusted HR (aHR) of overall cancer in patients with PsA was 1.20 (95% CI 1.02 to 1.41). When non-melanoma skin cancer was excluded, the risk of cancer did not show a significant increase in patients with PsA (aHR 1.16, 95% CI 0.98 to 1.37). Among specific cancers, the risk of non-melanoma skin cancer (aHR 3.64 [95% CI 1.61 to 8.23]), lymphoma (aHR 2.63 [95% CI 1.30 to 5.30]) and thyroid cancer (aHR 1.83 [95% CI 1.18 to 2.85]) was higher in patients with PsA than in the controls.

“The association between PsA and an increased risk of cancer was significant in relation to hematological cancer,” the authors noted. In subgroup analysis, “a significant association between PsA and cancer was observed in patients over 65 years of age and in women.”

Limitations of the study included its retrospective design, the short follow-up duration, and the relatively young age of the participants. Since the study was conducted only in Koreans, there is a limit to generalizing the results to other populations.

References

1. ^{Eun Y, Hwang J, Seo GH, Ahn JK. Risk of cancer in Korean patients with psoriatic arthritis: a nationwide population-based cohort study. RMD Open. 2023;9(1):e002874. doi:10.1136/rmdopen-2022-002874}