Jeremie Calais, MD, MSc, discusses the game-changing prostate cancer imaging agent PSMA. He reviews recent studies and how PSMA PET imaging can be used to inform strategies in prostate cancer treatment.
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Jérémie Calais, MD, MSc, Associate Professor of Nuclear Medicine and Theranostics in the Department of Molecular and Medical Pharmacology at the University of California, Los Angeles (UCLA), Director of the UCLA Theranostics Program, and Director of the Clinical Research Program of the Ahmanson Translational Theranostics Division discusses how to integrate prostate-specific membrane antigen (PSMA) positron emission tomography (PET) findings into treatment algorithms. Dr. Calais explains that PSMA PET results in new staging categories, has predictive value, and has value in response assessment. He emphasizes that inclusion criteria of randomized phase-3 trials must include PSMA PET staging/screening/selection for PSMA PET to be integrated into treatment algorithms.
Read MoreJeremie Calais, MD, MSc, Assistant Professor and Director of the Clinical Research Program in the Ahmanson Translational Theranostics Division of the Department of Molecular and Medical Pharmacology at UCLA, discusses PSMA diagnostics and compares imaging modalities to establish which modality is ideal for prostate cancer staging. He shares the FDA guidelines, stating that Ga 68 PSMA-11 is to be used for patients with prostate cancer (PCa) with suspected metastasis who are candidates for definitive therapy, and with suspected recurrence based on elevated serum prostate-specific antigen (PSA) level. Dr. Calais summarizes two trials used to support FDA approval of the diagnostic agent, including one on biochemical recurrence localization showing an overall detection rate of 75%, and another on primary nodal N1 staging that shows a sensitivity of 40% and a specificity of 95% for Ga 68 PSMA-11. Dr. Calais also notes the weaknesses of PSMA-11, including PET/CT’s inability to detect microscopic cancer cells, the way bone trauma in the ribs can lead to false positives, the challenge of accurately reading faint uptake lymph nodes, and how urine can disrupt analysis of the prostate fossa. Dr. Calais then compares PSMA against fluciclovine, finding that PSMA has a 30% higher detection rate; and against conventional imaging, finding that PSMA has a 27% higher rate of accuracy, as well as higher sensitivity and specificity. He also compares PSMA and local staging with MRI, highlighting a study on intra-prostatic tumor detection that shows a negligible difference in detection rates, as well as two studies on PSMA PET for biopsy guidance that show PSMA PET’s effectiveness in detecting especially challenging cancer. Dr. Calais concludes that PSMA PET/CT should replace other imaging modalities for prostate cancer staging and should be used as a complement to MRI for intra-prostatic tumor detection and staging.
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Jeremie Calais, MD, MSc, Assistant Professor and Director of the Clinical Research Program of the Ahmanson Translational Theranostics Division at UCLA, discusses the use of prostate-specific membrane antigen PET imaging, or PSMA PET, in diagnosing advanced prostate cancer. Noting that PSMA PET is currently the most sensitive imaging technique, he reviews well-known studies, STOMP and ORIOLE, and shares patient success stories of PSMA PET guided therapy. PSMA PET is able to detect tumor deposits of 4.5 mm with 90% accuracy and 2.3 mm with 50% accuracy making it more effective in locating disease migration. However, there will still be some micrometastases that are too small to yet be detected by PSMA PET. Because active distant lesions are not successfully identified under all imaging types, Dr. Calais proposes including the modality employed when stating a patient’s disease progression; for example, “mCRPC by PSMA-PET,” thereby expressing the means by which the disease stage was determined. PSMA PET can be used to follow disease mutation and more quickly identify non-metastatic castration-resistant prostate cancer.
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