Los Angeles -- Compared to conventional imaging techniques, prostate specific membrane antigen (PSMA) PET imaging provides superior detection of bone metastases in prostate cancer patients a critical indicator of a patient's long-term survival. Outcomes data revealed that patients with even just one bone metastasis experience faster disease progression and worse overall survival. This research was presented at the Society of Nuclear Medicine and Molecular Imaging 2026 Annual Meeting.
Prostate cancer commonly spreads to bone, and for decades physicians have relied on bone scans and CT scans to detect this. These tools, however, have limitations, frequently missing small deposits of cancer that are already present and already changing a patient's prognosis. Newer PSMA PET scans use a radioactive tracer that attaches directly to a protein on prostate cancer cells, making it far more sensitive than conventional imaging. As a result, PSMA PET has become the gold standard for staging prostate cancer at major cancer centers.
"We know that PSMA PET scans are effective in detecting bone metastases, but we don't have the data to show what that means in terms of overall outcomes," said Surekha Yadav, MBBS, resident in the Department of Radiology and Biomedical Imaging at the University of California, San Francisco. "Our study sought to determine what happens to patients over time when PSMA PET finds just one to five bone metastases, yet the conventional scan looks completely normal."
The retrospective study followed 36 patients across two academic centers who had between one and five bone lesions on PSMA PET at initial diagnosis. Conventional imaging was reviewed to determine upstaging rates. Time to biochemical recurrence, castration-resistant prostate cancer, composite endpoints, and overall survival over a median of 25 months were calculated. Treatment patterns were also recorded.
More than 80 percent of patients had completely normal conventional imaging, despite having bone lesions detected on PSMA PET. Compared to the 984 patients in the same cohort with no bone metastases on PSMA PET, patients with even one to five bone lesions had more than five times the risk of progressing to treatment-resistant cancer, and nearly four times the risk of death.
"Treatment decisions made at the time of diagnosis have lasting consequences. If a patient's conventional imaging looks negative, they may be managed with a less intensive approach as if their cancer hasn't spread," said Yadav. "Our study shows that when PSMA PET finds bone metastases that conventional imaging misses, those patients are not in a gray zone. Their cancer behaves aggressively, they progress faster, and they die sooner. Many of them are currently being treated based on a bone scan that says everything looks fine."
According to Yadav, patients don't have to wait to take benefit from PSMA PET; it is already FDA-approved and available at major academic cancer centers, including the University of California, San Francisco and the University of California, Los Angeles. "What this research changes is not access to the scan, she said, it's what we do with the results. Until now, oncologists have had limited outcome data to guide how aggressively to treat patients whose PSMA PET finds bone metastases that conventional imaging misses. Our study provides that evidence."
Abstract 262291. "Longitudinal Outcomes of PSMA PET/CT-Detected Bone Oligometastases: A Two-Center Study," Surekha Yadav, Chae Moon Hong, Stellamaris Oluebube Nwihim, Abuzar Moradi Tuchayi, Robert R. Flavell, and Thomas Hope, University of California, San Francisco, California; and Jeremie Calais, University of California, Los Angeles, California.
