Fluciclovine F18 PET-CT scanning in patients with high risk primary prostate carcinoma

Objectives The performance of the investigational amino acid PET tracer fluciclovine F18 (aka FACBC) compared to histopathology was retrospectively evaluated in patients with high risk primary prostate carcinoma to investigate whether fluciclovine F18 PET-CT has utility for disease staging, prior to selection of definitive primary treatment.

Methods 86 patients with histologically confirmed primary prostate carcinoma underwent fluciclovine F18 PET-CT scanning, as part of their pre-treatment work up for disease staging at two sites in Norway. Scan data were compared to histopathological standard of truth, which was available for 61/86 subjects. Effectiveness endpoints included detection rate, sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV). Analyses were conducted at Subject and Region level.

Results Data were collected under a retrospective protocol, BED-001, in accordance with ICH GCP and the Declaration of Helsinki. Patient risk factors included: Gleason score was 蠅7 for 88% of patients (n=40/45), 64.7% were considered high risk by D’Amico criteria (n=55/85), median PSA at baseline was ~10 ng/mL (n=78). Prostate biopsy data was available for 61 patients and pelvic lymph node histology for 55. In the Prostate region the PPV of fluciclovine F18 was 100% compared to histopathology, with 91.8% sensitivity and detection rate. No data are presented for NPV and specificity since subjects were de facto confirmed prostate cancer patients, or the number of patients with negative standard of truth per region was insufficient to support these analyses. In the extra-prostatic region fluciclovine F18 detected disease in 37.3% of patients, mostly as a consequence of extension to include the pelvic lymph nodes. PPV, NPV, sensitivity and specificity were 59.1%, 70.3%, 54.2% and 74.3%, respectively. At Subject level, the PPV of fluciclovine F18 was 100%, with sensitivity and detection rate of 93.4%.

Conclusions Fluciclovine F18 PET-CT scanning is predictive for the detection of regional lymph node metastases. The detection of metastases is a critical factor affecting the choice of initial treatment for patients with prostate cancer, and our data support the utility of fluciclovine F18 PET-CT scanning as an aid to the detection of metastases in patients with high-risk prostate cancer.