Dual-Tracer Positron-Emission Tomography Using Prostate-Specific Membrane Antigen and Fluorodeoxyglucose for Staging of Prostate Cancer: A Systematic Review

PSMA PET is more accurate than conventional imaging (CT/bone scan) for staging of intermediate- or high-risk prostate cancer (PCa), but 5–10% of primary tumours have low PSMA ligand uptake. FDG PET has been used to further define disease extent in end-stage castrate-resistant PCa and may be beneficial earlier in the disease course for more accurate staging. The objective of this study was to review the available evidence for patients undergoing both FDG and PSMA PET for PCa staging at initial diagnosis and in recurrent disease. A systematic literature review was performed for studies with direct, intraindividual comparison of PSMA and FDG PET for staging of PCa. Assessment for radioligand therapy eligibility was not considered. Risk of bias was assessed. 543 citations were screened and assessed. 13 case reports, three retrospective studies, and one prospective study were included. FDG after PSMA PET improved the detection of metastases from 65% to 73% in high-risk early castration-resistant PCa with negative conventional imaging (M0). Positive FDG PET was found in 17% of men with negative PSMA PET for postprostatectomy biochemical recurrence. Gleason score ≥8 and higher PSA levels predicted FDG-avid metastases in BCR and primary staging. Variant histology (ductal and neuroendocrine) was common in case reports, resulting in PSMA-negative FDG-positive imaging for 3 patients. Dual-tracer PET for PCa may assist in characterising high-risk disease during primary staging and restaging. Further studies are required to determine the additive benefit of FDG PET and if the FDG-positive phenotype may indicate a poorer prognosis.

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The “ProPSMA Study” clinical trial protocol: A prospective randomized multi-center study of the impact of Ga-68 PSMA PET/CT imaging for staging high-risk prostate cancer prior to curative-intent surgery or radiotherapy.

Journal of Clinical Oncology ◽

10.1200/jco.2019.37.7_suppl.tps138 ◽

2019 ◽

Vol 37 (7_suppl) ◽

pp. TPS138-TPS138 ◽

Cited By ~ 1

Author(s):

Michael Hofman ◽

Declan G. Murphy ◽

Scott Williams ◽

Tatenda Nzenza ◽

Alan Herschtal ◽

...

Keyword(s):

Prostate Cancer ◽

Clinical Trial ◽

High Risk ◽

Conventional Imaging ◽

Curative Intent ◽

High Risk Prostate Cancer ◽

Psma Pet ◽

Pet Ct ◽

Risk Prostate Cancer

TPS138 Background: Disease persistence or relapse following curative-intent surgery or radiotherapy of high-risk prostate cancer is not uncommon. This is attributable, in part, to a failure of accurate staging with diagnostic imaging being insensitive for detection of small volume metastatic disease. Prostate-specific-membrane-antigen (PSMA) positron emission tomography/computed tomography (PET/CT) is a new whole body scanning technique that enables visualisation of prostate cancer with high sensitivity. The hypotheses of this study are that PSMA-PET/CT (a) has improved diagnostic accuracy compared to conventional imaging, (b) should be used as a first-line diagnostic test for staging, (c) the improved diagnostic accuracy will result in significant management impact and (d) provides economic benefits when incorporated into the management algorithm. Methods: This is a 300 patient phase III multi-centre randomized study of patients with untreated high-risk prostate cancer defined by Gleason grade group 3-5, PSA ≥ 20ng/ml or clinical stage ≥ T3. Patients are randomized to Gallium-68-PSMA11 PET/CT or conventional imaging, consisting of computer tomography of the abdomen/pelvis and bone scintigraphy with SPECT/CT. Patients with negative, equivocal or oligometastatic disease cross-over to receive the other imaging arm. The primary objective is to compare the accuracy of PSMA-PET/CT to conventional imaging for detecting nodal or distant metastatic disease. Accuracy is defined by a pre-defined “ground truth” scoring system incorporating histopathologic, imaging and clinical follow-up at six months post randomisation. Secondary objectives include comparing management impact, the number of equivocal studies, the incremental value of second-line imaging in patients who cross-over, health economics, radiation exposure, inter-observer agreement and safety of PSMA-PET/CT. Longer term follow-up will also assess the prognostic value of a negative PSMA-PET/CT. 294 of 300 (98%) patients randomised at time of abstract submission. Clinical trial information: 12617000005358.

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