• f-MRI
• prostate cancer
• PSA
• [18F]FECH PET/CT

In prostate cancer patients with biochemical recurrence, distinguishing between local and distant failure is crucial to choose the most suitable treatment. In this study we assessed if the combination of f-MRI and [18F]FECH PET/CT could serve to optimize treatment decision making in patients with recurrent PCa after curative first-line treatment.
We enrolled 30 patients (mean age 72±7 yr) with biochemical relapse of PCa presenting about 6 yr after radical prostatectomy underwent consecutive DWI/DCE-MRI and [18F]FECH PET/CT dynamic PET imaging of the pelvic region + whole-body images, for a total of 60 studies. Each exam was classified as: indeterminate, negative or positive. Positive scans were further classified as positive for local relapse (candidate for standard salvage EBRT), oligo-metastatic (≤5 total lesions, candidate for EBRT) and pluri-metastatic disease (>5 total lesions, candidate for hormonal therapy, ADT).
The combination of DWI/DCE-MRI and [18F]FECH PET/CT detected disease recurrence in 27/30 patients: local relapse in 7, oligometastatic in 18 and plurimetastatic in 2. MRI was clearly superior in detecting local recurrence.On the other hand, [18F]FECH PET/CT detected more tumor lesions in case of metastatic disease. The combination of these two imaging modalities allowed in our patients an accurate definition of treatment planning, avoiding unnecessary systemic therapies.