Prevalence of clinically significant incidental findings by whole-body fludeoxyglucose F 18 positron emission tomography/computed tomography scanning in moderate-to-severe psoriasis patients participating in clinical trials

Abstract

Background: There has been an increase in the number of psoriasis treatments being investigated in clinical trials. Patients may have undiagnosed issues at the start of a study which may become identified during follow-up as incident medicinal conditions. The prevalence of incidental findings in patients with moderate-to-severe psoriasis presenting for clinical trials is unknown.

Objective: Determine the prevalence of incidentalomas and rate of malignancy identified by fludeoxyglucose F 18 (FDG) positron emission tomography/computed tomography (PET/CT) imaging in clinical trial patients with moderate-to-severe psoriasis.

Methods: A cross-sectional secondary analysis of patients with moderate-to-severe psoriasis who underwent FDG PET/CT scans at the baseline visit, before randomization, for 3 phase 4 clinical trials on vascular inflammation in psoriasis. Only patients without active infection, malignancy, or uncontrolled comorbidities were eligible for the clinical trials.

Results: A total of 259 healthy patients with moderate-to-severe psoriasis underwent an FDG PET/CT scan as part of the study procedures. In all, 31 patients (11.97%) (95% confidence interval [CI], 8.28-16.56) had clinically significant incidentalomas on the baseline FDG PET/CT scan. Univariate logistic regression demonstrated that with every increase of 10 years of age, there was an approximate 30% increased risk of discovery of an incidentaloma (odds ratio, 1.30; 95% CI, 1.01-1.68). Of those patients with findings suggestive of malignancy (n = 28), 6 were confirmed to have cancer, resulting in a 2.31% (95% CI, 0.9-5.0) prevalence of malignancy. The positive predictive value of a true cancer was 31.58% (range, 21%-54%).

Limitations: Generalizability and lost to follow-up.

Conclusion: Incidentalomas on FDG PET/CT imaging are common in otherwise healthy, asymptomatic patients with moderate-to-severe psoriasis in clinical trials. Our results can help inform interpretation of clinical trial safety data and emphasize the importance of compliance with cancer screening recommendations.

Keywords: FDG PET/CT; biologics; incidental findings; psoriasis; randomized controlled trials.