How to cite: Morris MJ, Calais J, and Shore ND. “Candidates and Follow-Up for Lu-177 PSMA.” August 15, 2025. Accessed Feb 2026. https://grandroundsinurology.com/candidates-and-follow-up-for-lu-177-psma/.
Summary
This expert panel discussion, moderated by Michael J. Morris, MD, Medical Oncologist, Memorial Sloan Kettering Cancer Center, New York, New York, reviews practical criteria for selecting candidates for Lu-177 prostate-specific membrane antigen (PSMA) radioligand therapy and outlines expectations for follow-up, imaging interpretation, and toxicity management. Dr. Morris is joined by Jérémie Calais, MD, PhD, Nuclear Medicine Physician, University of California, Los Angeles, Los Angeles, California; and Neal D. Shore, MD, Urologist, Atlantic Urology Specialists, Myrtle Beach, South Carolina; who examine how patient factors and imaging characteristics determine eligibility for treatment.
The experts compare the imaging criteria used in the VISION and TheraP trials. Dr. Morris notes that VISION required lesions to be PSMA-positive relative to liver reference but did not require fluorodeoxyglucose (FDG) imaging. In contrast, TheraP mandated PSMA-avid lesions with a standardized uptake value (SUV) maximum of ≥20 and required FDG positron emission tomography (PET) to rule out discordant, FDG-avid/PSMA-negative sites. These differences contributed to higher screen-failure rates in TheraP. Dr. Calais emphasizes that real-world practice often blends elements of both studies, adjusting eligibility to reflect clinical judgment rather than rigid trial thresholds.
The physicians present an imaging sequence illustrating a dramatic treatment response: a patient with extensive PSMA-avid disease and prostate-specific antigen (PSA) of 74 undergoes Lu-177 therapy. Follow-up imaging nine months later shows a substantial reduction in disease, and subsequent images, taken without additional systemic therapy, demonstrate continued stability, with the PSA declining to 0.25. This example raises the question of optimal post-therapy monitoring. The panel discusses the frequency of obtaining PSA, cross-sectional imaging, and post-treatment gamma scans.
Toxicity management is explored through a review of “on-target/on-tumor,” “on-target/off-tumor,” and “off-target/off-tumor” effects. Xerostomia, cytopenias, and renal insufficiency are highlighted as expected risks. The discussion reinforces that toxicity is mechanism-based: any tissue expressing PSMA or exposed to a nonspecific radioligand may be affected.
Overall, the panel outlines a practical, patient-centered approach to selecting candidates, applying imaging criteria, and structuring follow-up after Lu-177 PSMA therapy.
