Research reveals that nearly half of patients with high-risk prostate cancer, previously classified as non-metastatic by conventional imaging, actually have metastatic disease when evaluated by imaging technique advanced prostate-specific membrane antigen positron emission tomography (PSMA-PET).
- “PET” imaging or positron emission tomography makes it possible to measure the metabolic activity of the organ in 3D using the emissions produced by positrons resulting from the disintegration of a radioactive compound injected beforehand.
- PSMA is a weakly radioactive ligand, which, when injected into the bloodstream, binds to prostate specific antigen (PSA).
- PET makes it possible to evaluate the absorption of PSMA in prostate cancer cells and therefore to locate possible metastases;
- Traditional imaging, on the other hand, underestimates, in many cases, the extent of the spread of cancer. Unlike conventional imaging, which only provides anatomical details, PSMA-PET offers functional imaging that reveals the biological activity of cancer, which can significantly improve disease stage definition.
Lead author Dr. Jeremie Calais, Director of the Clinical Research Program in the Division of Translational Theranostics at the David Geffen School of Medicine at UCLA, summarizes: “Our study demonstrates the essential role of PSMA-PET imaging in the precise determination of the stage of prostate cancer, with a possible significant impact on therapeutic decisions”.
Better diagnosis, better therapeutic decision
This advanced imaging technology plays a vital role in re-staging cancer.
Clinical adoption of PSMA-PET in some treatment centers has significantly changed the diagnostic landscape, however treatment decisions often remain based on the results of clinical trials that have not incorporated this advanced imaging technique for patient selection. There therefore remains great room for therapeutic progress.
The study A post hoc retrospective cross-sectional study is conducted here using data from 182 patients with high-risk recurrent prostate cancers, initially diagnosed as limited to the prostate and participating in the EMBARK trial. The clinical trial had already demonstrated that adding enzalutamide, a type of hormone therapy, to androgen deprivation therapy significantly improved metastasis-free survival. However, conducted using conventional imaging to classify patients, the trial had most likely underestimated the extent of disease in some cases. In the new analysis,
- PSMA-PET can detect cancer metastases in 46% of patients, even though traditional imaging had previously detected no evidence of cancer spread in these same patients;
- still based on PSMA-PET, 24% of patients had even 5 or more lesions missed by conventional imaging.
These initial data challenge the interpretation of previous study findings, such as those from the EMBARK trial, and support the inclusion of PSMA-PET for patient selection in clinical trials. It also highlights the need to reevaluate therapeutic strategies for many patients.
“We are confident that PSMA-PET will continue to advance prostate cancer staging and guide personalized therapies.”
