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Prevalence of Incidental Findings in Psoriasis Scans

J Am Acad Dermatol; ePub 2019 Jan 14; Wan, et al

Incidentalomas on FDG-PET/CT imaging are common in otherwise healthy, asymptomatic clinical trial patients with moderate-to-severe psoriasis, according to a recent study. Therefore, these results can help inform clinical trials safety data interpretation and emphasizes the importance of compliance with cancer screening recommendations. Researchers conducted a cross-sectional secondary analysis of moderate-to-severe psoriasis patients who underwent FDG-PET/CT scans at the baseline visit, prior to randomization, for 3 phase 4 vascular inflammation in psoriasis clinical trials. Only patients without active infection, malignancy, or uncontrolled comorbidities were eligible for the clinical trials. They found:

  • 259 healthy patients with moderate-to-severe psoriasis underwent an FDG-PET/CT scan as part of study procedures.
  • 31 patients (11.97%) had clinically significant incidentalomas on the baseline FDG-PET/CT scan.
  • Univariate logistic regression demonstrated that with every increase in age of 10 years, there was an approximate 30% increased risk of discovering an incidentaloma (OR=1.30).
  • Of the findings suspicious for malignancy (n=28), cancer was confirmed in 6 patients resulting in a 2.31% prevalence of malignancy.
  • Positive predictive value of a true cancer was 31.58%.

Wan MT, Torigian DA, Alavi A, et al. Prevalence of clinically significant incidental findings by whole-body FDG-PET/CT scanning in moderate-to-severe psoriasis patients participating in clinical trials. [Published online ahead of print January 14, 2019]. J Am Acad Dermatol. doi:10.1016/j.jaad.2019.01.008.


This is the first, large, multi-center study of its kind that reports the frequency of incidental findings, such as malignancy, with the use of non-invasive imaging of patients who were otherwise asymptomatic with moderate-to-severe psoriasis. The risk increases 30% every 10 years and 2.3% of the subjects had serious unrecognized cancers, according to the study. Therefore, this data can provide an estimate of the prevalence of cancer in the moderate-to-severe psoriasis population. It would be interesting if the same rate applies for subjects with mild psoriasis as well as psoriatic arthritis. In conclusion, this study emphasizes the importance of psoriatic patients to undergo age-appropriate cancer screening.—Paul S. Yamauchi, MD, PhD; Clinical Assistant Professor of Dermatology David Geffen School of Medicine at UCLA; Harbor-UCLA Medical Center Division of Dermatology; Adjunct Associate Professor John Wayne Cancer Institute.