Prostate-specific membrane antigen PET/CT using fluorine-18 PSMA-1007 is being used to stage prostate cancer before treatment. Beyond image quality, the tracer’s practical features support routine deployment and may help visualise pelvic disease. A systematic review and metaanalysis pooled results from clinical studies that compared imaging directly with histopathology for tumour characterisation, lymph nodes and distant spread. Nineteen studies involving 1,420 patients were included. The analysis also considered how PSMA-1007 performed next to conventional imaging and alternative tracers when head-to-head data were available and summarised reading nuances and safety information relevant to day-to-day reporting.
Practical Features and Review Scope
The literature search covered PubMed/MEDLINE through 4 July 2024 and selected clinical studies that used histopathology as the reference. Recurrent disease and tracers other than 18F-PSMA-1007 were excluded. Ten studies contributed to T staging (739 patients), eight to N staging (865 patients) and one to M staging (79 patients). Where appropriate, results were synthesised at patient and lesion levels and heterogeneity was explored through sensitivity analyses.
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Several tracer characteristics matter for clinical workflow. The 110-minute half-life enables off-site cyclotron production, stable supply and imaging schedules that accommodate busy departments. Hepatobiliary excretion reduces urinary activity, so the bladder tends to be less intense than with the alternatives. This can make pelvic interpretation more straightforward, particularly around the prostate and seminal vesicles. Resolution properties reported across the evidence suggested the potential to depict small lesions in certain contexts, although image quality still depends on acquisition and reconstruction protocols used locally.
Local and Nodal Staging Performance
Across T staging reports, patient-level sensitivity and specificity varied, with many studies reporting higher specificity. Pooled results for extraprostatic extension showed a sensitivity of 54% and a specificity of 92%. For seminal vesicle invasion, pooled sensitivity reached 57%, while specificities differed across studies and did not align sufficiently to allow a pooled estimate with low heterogeneity. Head-to-head comparisons against multiparametric MRI showed mixed results that depended on the endpoint assessed and the study design, some favoured 18F-PSMA-1007 on sensitivity or specificity, others favoured MRI.
For lymph nodes, 18F-PSMA-1007 PET/CT generally achieved high specificity with variable sensitivity when compared with histopathology. After sensitivity analyses to address heterogeneity, pooled patient-level performance reached 42% sensitivity and 94% specificity. At the lesion level, pooled sensitivity was 73% and specificity 99%. Where whole-body or pelvic MRI was compared directly, PET/CT tended to show higher sensitivity with broadly similar specificity. These findings suggest a role for PET/CT in identifying nodal disease that might be missed by structural imaging alone, while recognising that small or micrometastatic deposits can still evade detection.
Whole-Body Assessment, Reading Nuances and Safety
Only one prospective study in high-risk disease addressed distant staging head-to-head. On a patient basis, 18F-PSMA-1007 PET/CT showed higher sensitivity than bone scintigraphy, CT, SPECT/CT and whole-body MRI across analyses that handled equivocal findings differently. Specificity was reported alongside those results for each reader and supported the comparative advantage on detection without indicating a trade-off that would hinder interpretation.
Reading considerations are important, particularly in bone. Unspecific uptake has been described for 18F-PSMA-1007, with false positives linked to benign processes such as fractures and degenerative change. Structured reporting and awareness of these pitfalls were emphasised in the evidence base. When indeterminate foci are seen at primary staging, follow-up aligned with clinical context, including monitoring of prostate-specific antigen after curative-intent treatment, formed part of management strategies discussed in the included sources.
Safety findings were consistently reassuring. Across the collated clinical experience, no considerable adverse events were attributed to 18F-PSMA-1007. In a multicentre randomised phase 3 comparison with 18F-fluorocholine for biochemical recurrence localisation, no adverse events were considered related to PSMA-1007 in 191 patients. A European summary of product characteristics reported no undesirable effects in more than 1,000 patients. These data support routine clinical use when the tracer is available and local protocols are established for acquisition and reporting.
18F-PSMA-1007 PET-based imaging offers a practical, single-session approach to primary prostate cancer staging, combining tumour, nodal and whole-body assessment. The meta-analysis indicated high specificity with variable sensitivity for both local and nodal disease and higher patient-level sensitivity than several conventional modalities for distant staging in one prospective comparison. Together with favourable logistics and reassuring safety data, these findings support integration of 18F-PSMA-1007 PET/CT alongside MRI according to local pathways. For clinical teams, the key is to leverage complementary strengths while applying structured interpretation to minimise false positives, particularly in bone, so that imaging informs treatment decisions with clarity and confidence.
Source: Journal of Nuclear Medicine
Image Credit: iStock
