A Closer Look at Urinary Activity and PET Radiopharmaceuticals for Prostate Cancer Imaging

Urinary activity, reportedly a common feature of prostate-specific membrane antigen positron emission tomography (PSMA PET) radiopharmaceuticals, can have an adverse impact on imaging interpretation for detection of new or recurrent prostate cancer.

At initial staging, intense urinary activity with PET radiopharmaceuticals can obscure surrounding areas of the bladder, including the prostate, primary prostate lesions below the bladder, small lymph nodes around the bladder and invasion of the primary prostate tumor into surrounding structures such as the seminal vesicles, noted Phillip Kuo, M.D., Ph.D., F.A.C.R., during a recent interview at the Society of Nuclear Medicine and Molecular Imaging (SNMMI) conference in Chicago.

Dr. Kuo also pointed out that high urinary activity can make it more challenging to diagnose recurrence at the vesicourethral anastomosis, the most common site for prostate cancer recurrence.

(Editor’s note: For related content, see “PSMA PET Imaging May Offer Key Prognostic Markers for Prostate Cancer” and “Can an Emerging PSMA/PET Agent Improve Detection of Prostate Cancer Recurrence in Patients with Low PSAs?”)

However, in a recent study looking at phase 3 from the SPOTLIGHT and LIGHTHOUSE trials, Dr. Kuo and colleagues examined the use of the injectable PET imaging agent flotufolastat F 18 (POSLUMA®, Blue Earth Diagnostics) in 712 patients with either newly diagnosed or recurrent prostate cancer. The study findings, presented at the SNMMI conference, demonstrated that for 96 percent of the cohort, it was possible to distinguish between urinary activity and disease uptake.

“In the vast majority of the cases, urinary activity (with flotufolastat F 18) is low enough in the ureters and bladder that we think it will not potentially affect your ability to detect disease in the pelvis,” noted Dr. Kuo, a professor of medical imaging, biomedical engineering, and medicine at the University of Arizona College of Medicine.

For more insights from Dr. Kuo, watch the video below.