In Elderly, Psoriasis Heightens Risk of Malignancy

Elderly patients with psoriasis appear to be at a higher risk of being diagnosed with cancer, according to a new report. The analysis is contained in a research letter published in the Journal of the American Academy of Dermatology.

Corresponding author Alexandra Finstad, MD, BScH, BAH, of the University of Toronto, and colleagues, noted that comorbidities including psoriasis have been associated with a greater risk of cancer, and age has been identified as an independent risk factor for cancer. Thus, they wanted to see how the combination of older age and psoriasis might affect a patient’s risk of malignancy.

The authors used data from the Ontario Cancer Data Linkage Program covering the years 2004-2017. Patients were included in the analysis if they were at least 70 years old, and they were added to the study once they turned 70 if they had been previously diagnosed with psoriasis.

The authors identified a total of 42,684 people with psoriasis and matched them to 430,002 controls. They found a higher rate of cancer in the psoriasis group (27.54%) compared to the controls (18.43%). That translated to a higher relative risk (RR) of malignancy of 1.49 (95% confidence interval [CI] 1.47-1.52).

When the authors excluded patients with a history of cancer, they found the risk associated with psoriasis was even higher.

“Elderly patients with psoriasis had an approximately 50% increased malignancy risk compared with that in elderly patients without psoriasis, increasing to 80% after controlling for a history of cancer,” they said.

When investigators looked at specific cancer types, they found the highest risk was for pancreatic cancer (RR 5.88; 95% CI, 4.86-7.11) and liver and intrahepatic bile duct cancers (RR 5.34; 95% CI, 4.29-6.64).

The authors also looked at patients with a history of concurrent psoriatic arthritis (PsA) and psoriasis. In those patients, the relative risk of malignancy was 1.33 (95% CI, 1.25-1.41) in all patients and 1.52 (95% CI, 1.37-1.68) in patients with no history of cancer.

However, they found patients with both PsA and psoriasis had a slightly lower relative risk than patients with psoriasis alone (0.93; 95% CI, 0.87-0.99).

The authors noted that their study was based solely on age and psoriasis history, and so they could not adjust their findings for potential confounders like lifestyle factors and disease severity. They added that because the province’s cancer registry does not include data for nonmelanoma skin cancers, their analysis likewise did not include those cancer types. One final limitation, they said, is that people with psoriasis are more likely to receive treatment more often, which may give them a better opportunity to have malignancies identified by their physicians.

The authors said these findings carry important implications for physicians treating patients with psoriasis.

“[W]hen managing psoriasis in the elderly, it is important to consider their increased malignancy risk, with additional studies needed on the malignancy risk associated with psoriasis treatment and severity,” they concluded.

Reference

Finstad A, Glockler-Lauf SD, Almuhanna N, Saskin R, Alhusayen R. Investigating the risk of malignancy in elderly patients with psoriasis: A population-based retrospective matched cohort study. J Am Acad Dermatol. 2023;88(5):1129-1131. doi:10.1016/j.jaad.2022.08.017