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."