39 An elevated PSA level in the blood may indicate prostate cancer, but it does not allow for a definitive diagnosis. Where suspicion remains, a tissue sample is usually taken from the prostate. A new study by the Medical University of Vienna shows that a specialised imaging method known as PSMA-PET/CT could provide important additional information before a biopsy is carried out. In an analysis of 194 patients, the method detected 91% of clinically relevant prostate cancers. The findings, from a research team led by Marcus Hacker, Head of the Division of Nuclear Medicine at the Department of Biomedical Imaging, were published in the inaugural issue of the new journal The Lancet Medical Imaging & Theranostics. PSMA-PET/CT combines two imaging techniques. In Positron Emission Tomography (PET), a small amount of a radioactively labelled substance is administered that binds specifically to Prostate-Specific Membrane Antigen (PSMA), a protein particularly abundant on prostate cancer cells. This allows suspicious areas to be visualised. A simultaneous Computed Tomography (CT) scan provides precise images of the body’s structures, enabling these areas to be anatomically located. As part of a retrospective analysis of the randomised Phase 3 RAPID trial, the research team, led by Holger Einspieler and Sazan Rasul, investigated the potential value of PSMA-PET/CT in patients with elevated PSA levels and suspected prostate cancer before biopsy. Of 77 patients with clinically significant prostate cancer confirmed by tissue examination, 70 were detected by PSMA-PET/CT, a detection rate of 91%. The test’s predictive value was equally strong when results were normal: in 91% of those cases, no clinically significant tumour was present. Over a median follow-up period of 35 months, the researchers found that 23 of 24 patients who went on to develop an aggressive course of the disease had already been identified by PSMA-PET/CT. The results suggest PSMA-PET/CT could play a role in the initial investigation of suspected prostate cancer in future. In particular, a normal scan result could help clinicians better assess which patients actually require a tissue sample, potentially avoiding unnecessary biopsies. Whether and how the method could be integrated into routine diagnostics will need to be examined in further studies. “Our results show that PSMA-PET/CT may be able to provide valuable information at a very early stage of the diagnostic work up. The high diagnostic value of a normal result is particularly relevant here. In future, this could help to make better decisions about which patients actually require a biopsy,” said Hacker. Prostate cancer remains one of the most common cancers diagnosed in men in the UK and worldwide. Current pathways often rely on PSA testing followed by multiparametric MRI and then biopsy when suspicion remains. Biopsies carry risks including infection, bleeding, and discomfort, and can detect clinically insignificant disease that may not require immediate treatment. Imaging techniques that improve risk stratification before tissue sampling therefore hold clear clinical interest. PSMA-targeted PET imaging has already established a strong role in staging confirmed prostate cancer and detecting recurrence after treatment. The Vienna analysis extends consideration of the technology earlier in the pathway, specifically for men with raised PSA and clinical suspicion before any biopsy has been performed. The research team emphasises that these findings come from a retrospective analysis of data generated within the RAPID trial framework. Prospective evaluation in broader patient populations and different healthcare settings will be required before any change to standard diagnostic algorithms can be recommended. Questions remain around optimal patient selection, cost-effectiveness, availability of radiotracers, scanner capacity, and how PSMA-PET/CT would interact with existing multiparametric MRI pathways used in many centres. Even so, the findings add to a growing body of evidence that molecular imaging directed at the prostate-specific membrane antigen can refine decision-making, identifying men at higher likelihood of harbouring aggressive disease as well as those in whom significant cancer is unlikely. Further studies will determine whether this early diagnostic application can reduce the number of biopsies performed while maintaining, or even improving, detection of cancers that truly require intervention. The publication in the first issue of The Lancet Medical Imaging & Theranostics brings these results to the attention of the wider imaging and oncology communities at a time when interest in PSMA-based diagnostics and therapies continues to expand.