Impact of gated FDG PET/CT on the staging of patients with suspected or proven newly diagnosed advanced epithelial ovarian, fallopian tube, and primary peritoneal cancer: results from a non-randomized, phase II clinical trial.

Objective: Imaging for staging ovarian cancer is important to determine the extent of disease. The primary objective of this study was to compare gated 18F-fluorodeoxyglucose positron emission tomography coupled with computed tomography (FDG PET/CT) and standard CT scan with intravenous contrast to diagnose thoracic involvement in patients with advanced ovarian cancer prior to treatment. The secondary objective was to estimate changes in the International Federation of Gynecology and Obstetrics (FIGO) stage and clinical management resulting from gated PET/CT.

Methods: The IMAGE trial is a non-randomized phase II clinical trial comparing standard CT scanning with gated PET/CT in diagnosing thoracic involvement in a non-selected group of patients with suspected ovarian cancer on a contrast CT scan. Three sets of PET images were obtained comprising an ungated 2 min whole body image, a static 7.5 min image of the upper abdomen and thorax, and a gated end-expiratory image over the upper abdomen and thorax. Images were evaluated for specificity, sensitivity, diagnostic accuracy, and the proportion of patients with changes in FIGO stage and subsequent clinical management was compared between imaging techniques.

Results: A total of 84 patients were enrolled based on a standard CT scan, 67 of whom were eligible for gated PET/CT scans. Diagnostic accuracy with gated PET/CT was more than 80% for lesions in lung, liver, extra-abdominal sites, and pleura, but less than 50% for extra-abdominal lymph nodes. Compared with CT scan at baseline, 46% of patients who had 7.5 min gated PET/CT had disease upstaged from stage III to IV, and 8% had disease downstaged from stage IV to III. However, this led to a change of management in only 5% of patients.

Conclusions: Gated PET/CT enables upstaging; however, in our institution it altered clinical management only in a minority of patients.

Trial Registration Number: NCT02258165.