The Continuum of Metastatic Prostate Cancer: Interpreting PSMA PET Findings in Recurrent Prostate Cancer

Abstract

Conventional imaging has been the standard imaging modality for assessing prostate cancer recurrence and is utilized to determine treatment response to therapy. Molecular imaging with PSMA PET–CT has proven to be more accurate, sensitive, and specific at identifying pelvic or distant metastatic disease, resulting in earlier diagnosis of advanced disease. Since advanced disease may not be seen on conventional imaging, due to its lower sensitivity, but can be identified by molecular imaging, this reveals that metastatic prostate cancer occurs on a continuum from negative PSMA PET–CT and negative conventional imaging to positive PSMA PET–CT and positive conventional imaging. Understanding this continuum, the accuracy of these modalities, and treatment related outcomes based on imaging, will allow the clinician to counsel patients on management. This review will highlight the differences in conventional and molecular imaging in prostate cancer and how PSMA PET–CT can be used for the management of prostate cancer patients in different clinical scenarios, while providing cautionary notes for overtreatment.

The Impact of PSMA PET/CT on Modern Prostate Cancer Management and Decision Making—The Urological Perspective

“…In patients who underwent second-line imaging, management change occurred in 5% of patients following conventional imaging and 27% of patients following PSMA PET/CT. However, while prostate imaging by PSMA PET/CT detects sites of prostate cancer recurrence inside and outside of the treatment area at lower PSA levels, one must take into consideration the known “Will Rogers effect” [ 10 ], potentially triggering earlier treatment initiation and raising real-life questions regarding the clinical impact of such findings on its impact on disease-specific and overall survival rather than other disease pathway timepoints [ 11 ].…”

Patients with Positive Lymph Nodes after Radical Prostatectomy and Pelvic Lymphadenectomy—Do We Know the Proper Way of Management?

“…This study suggests that that some patients with negative PSMA PET/CT could benefit from salvage RT (SRT). Others, with positive LN on PSMA PET/CT and negative with conventional imaging, should be counseled on SRT-or ADT-based combinations [41]. Nevertheless, there is still no information on PSMA PET results in pN+ patients and the impact it would have on the management in this heterogeneous group.…”

Bone Scintigraphy versus PSMA-Targeted PET/CT or PET/MRI in Prostate Cancer: Lessons Learned from Recent Systematic Reviews and Meta-Analyses

“…PSMA is a membrane antigen that is overexpressed in the majority of PC cells and it is an ideal target for PC diagnosis and therapy (theranostics). In particular, PSMA-targeted PET/CT or PET/MRI (using PSMA-targeting radiopharmaceuticals labelled with 68 Ga, 18 F, or 64 Cu) is gaining importance in the staging and restaging of PC [ 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 ]. The accurate diagnosis of bone metastases is relevant in guiding local and systemic treatment in PC.…”