Prospective comparison of FCH PET/CT, contrast-enhanced CT and MRI in recurrent prostate cancer

1420 Objectives In the comparative pivotal study CH02 of Iasocholine®, a preparation of fluorocholine(18F) (FCH), 209 patients were included for localisation of recurrence of prostate cancer (PC) after initial radical treatment, generally suspected on rising serum PSA levels (PSA median=5 range=0.01-137). Methods The referring urologist was free to choose conventional imaging (CI) according to the clinical context: contrast-enhanced CT (CECT) or MRI. The written reports of the referring urologist during follow-up of at least 6 months (FU) were used by an independent urologist assessor (IA) to determine the impact of FCH PET/CT on management. To compare diagnostic performance, FCH PET/CT and CI comparators were blind read by NM/radiology specialists respectively. The standard-of-truth (SOT) was evaluated by IA blinded to the results of FCH and of CI: 13 sites were defined; a site was “positive” only if a lesion was malignant at histology or if irradiating a lesion resulted in a significant drop of PSA; a site was “negative” only if no malignancy was found at histology and during FU with dedicated investigations. The patient level was “negative” if all sites were “negative” and the PSA levels declined during follow-up spontaneously or without anticancer therapy (antibiotics…). Results The rate of change in scheduled management was 66/209=32% and an impact on diagnostic thinking was reported in 16/209=8% other patients. SOT was determined for 168 sites and 76 patients (PSA median=5.2 range=0.06-137). The following significant differences in sensitivity were observed: - superiority of FCH over CECT both per-patient (88% vs. 37% n=41) and per-site (80% vs. 15% n=66) - superiority of FCH over MRI per-site (76% vs. 53% n=38) Concerning specificity, there were only 7 negative cases but 64 negative sites; no significant difference was found, although there was a trend for superiority of FCH over MRI (site-based 93% vs. 86% n=14). Conclusions FCH PET/CT had a 40% impact rate and better sensitivity as compared to both CECT and MRI, particularly site-based sensitivity. Research Support Phase III study sponsored by Iason