With the availability of ultra-sensitive PSA assays, early biochemical relapse (eBCR) of prostate cancer is increasingly being detected at values much lower than the conventional threshold of 0.2 ng/ml. Accurate localisation of disease in this setting may allow treatment modification and improved outcomes, especially in patients with pelvis-confined or extra-pelvic oligometastasis (defined as up to three pelvic nodal or distant sites). We aimed to measure the detection rate of Ga-PSMA-HBNED-CC (PSMA)-PET/CT and its influence on patient management in eBCR of prostate cancer following radical prostatectomy (RP).
We retrospectively identified 28 patients who underwent PSMA-PET/CT for post-RP eBCR (PSA < 0.5 ng/ml) at our tertiary care cancer centre. Two nuclear medicine physicians independently recorded the sites of PSMA-PET/CT positivity. Multidisciplinary meeting records were accessed to determine changes in management decisions following PSMA-PET/CT scans.
The mean age of patients was 65.6 years (range: 50-76.2 years); median PSA was 0.22 ng/ml (interquartile range: 0.15 ng/ml to 0.34 ng/ml). Thirteen patients (46.4%) had received radiotherapy in the past. PSMA-PET/CT was positive in 17 patients (60.7%). Only one patient had polymetastasis (> 3 sites); the remainder either had prostatectomy bed recurrence (n = 2), pelvic oligometastasis (n = 10), or extra-pelvic oligometastasis (n = 4). PSMA-PET/CT resulted in management change in 12 patients (42.8%), involving stereotactic body radiotherapy (n = 6), salvage radiotherapy (n = 4), and systemic treatment (n = 2).
Our findings show that PSMA-PET/CT has a high detection rate in the eBCR setting following RP, with a large proportion of patients found to have fewer than three lesions. PSMA-PET/CT may be of value in patients with early PSA failure, and impact on the choice of potentially curative salvage treatments.
European journal of nuclear medicine and molecular imaging. 2019 Jan 08 [Epub ahead of print]
Usman Bashir, Alison Tree, Erik Mayer, Daniel Levine, Chris Parker, David Dearnaley, Wim J G Oyen
Division of Radiotherapy and Imaging, Centre for Cancer Imaging/SRD, The Institute of Cancer Research, 15 Cotswold Road, London, Sutton, SM2 5NG, UK., The Royal Marsden NHS Foundation Trust, Department of Urology & Department of Surgery & Cancer, Imperial College London, London, UK., Division of Radiotherapy and Imaging, Centre for Cancer Imaging/SRD, The Institute of Cancer Research, 15 Cotswold Road, London, Sutton, SM2 5NG, UK. .