Quantification of Equivocal Findings in F18-Fluciclovine PET/CT Scans for Biochemical Recurrence of Localized Prostate Cancer

Abstract

PET/CT scans are being used to assess patients who have experienced biochemical failure following surgery or radiation therapy for localized prostate cancer. We aimed to evaluate the language used in report impressions and to determine the level of confidence that radiologists have when reporting on lesions in various anatomic sites. Between 2015 and 2021, 295 F18-fluciclovine PET/CT scan reports were identified. Thirteen phrases commonly used by radiologists in the report impression section to describe a lesion of interest were identified and categorized into three confidence categories: definitive (positive and negative), likely (consistent with, most likely, favors, probable), and unsure (suspicious for, concerning for, non-specific, conspicuous, compatible with, borderline, unknown). The use of definitive language varied depending on the anatomic site, with the highest use in bone (87.1%) and the lowest use in the intact prostate (34.6%). In patients with a PSA < 0.5, there was the highest degree of definitive certainty (89.2%), whereas in patients with a PSA > 1, there was the least definitive certainty (66.2%). The language used in these reports has not been standardized, with definitive, likely, and unsure findings reported in 68.6%, 9.7%, and 21.7% of scans, respectively.