Who this is for
PSMA PET prostate cancer imaging can sometimes find cancer that CT scans and bone scans miss.
This article is for men with high-risk prostate cancer who are trying to understand why a CT scan or bone scan may look normal, but a PSMA PET scan finds cancer.
It may also be helpful for patients seeking prostate cancer treatment or a prostate cancer second opinion in Melbourne, Australia, Sri Lanka, Maldives, Indonesia or the Philippines.
Clinical Observation
A 65-year-old gentleman comes to see me after a routine blood test shows a PSA of 16.
An MRI of the prostate demonstrates a suspicious lesion.
A biopsy confirms Gleason 4+4 prostate cancer.
Naturally, the next question is:
“Has the cancer spread?”
A CT scan is performed.
A bone scan is performed.
Both are reported as normal.
The patient and his family feel relieved.
A PSMA PET scan is then arranged.
Suddenly, a lymph node in the pelvis lights up.
The patient looks confused and asks:
“How can one scan be normal and another show cancer?”
That question is exactly why the proPSMA study matters.
PSMA PET prostate cancer: What was the proPSMA trial?
The proPSMA trial studied men with newly diagnosed high-risk prostate cancer who needed staging before curative-intent treatment.
In simple terms, the study asked:
“Is PSMA PET better than CT and bone scan for finding whether prostate cancer has spread?”
Study Design
The trial included 302 men.
Researchers recruited patients from 10 Australian centres.
Patients were randomly assigned to one of two staging approaches:
- PSMA PET-CT
- Conventional imaging with CT scan and bone scan
Key Results
- PSMA PET was more accurate.
Diagnostic accuracy was 92% with PSMA PET compared with 65% using CT and bone scan. - The improvement was clinically meaningful.
This was a 27% absolute improvement in diagnostic accuracy. - PSMA PET changed treatment planning more often.
Management changed in 28% of patients who had PSMA PET, compared with 15% of patients who had conventional imaging. - PSMA PET helped explain confusing scan results.
A CT scan and bone scan may look normal, while a PSMA PET scan still detects prostate cancer. This does not mean the cancer suddenly appeared. It means PSMA PET is a more sensitive test.
What do these results mean for patients?
Let’s go back to the 65-year-old gentleman described earlier.
Ten years ago, doctors may have told him that his scans were clear.
Today, PSMA PET may identify a pelvic lymph node that older scans would have missed.
The cancer has not changed.
Our ability to see it has.
That single finding may influence the radiotherapy field, the duration of hormone therapy, whether treatment should be intensified, and whether clinical trial participation is appropriate.
This is why PSMA PET has rapidly become part of routine staging for high-risk prostate cancer.
Why doctors may still consider CT and bone scans
Patients sometimes ask:
“If PSMA PET is more accurate, why would I still need a CT scan or bone scan?”
The answer depends on the clinical situation.
PSMA PET provides a more accurate picture of where the cancer is located today.
However, many landmark prostate cancer trials, including STAMPEDE, used conventional imaging with CT scans and bone scans.
This means doctors sometimes need to interpret modern PSMA PET findings alongside evidence that was generated using older imaging definitions.
In some situations, CT scans and bone scans may still help provide context for treatment decisions.
The PSMA PET tells us where the cancer appears to be now.
The older imaging framework helps us understand how major clinical trial evidence applies.
Together, this can provide a clearer roadmap for treatment planning.
This approach can be particularly useful when providing prostate cancer second opinions in Melbourne and for patients seeking specialist advice from Australia, Sri Lanka, Maldives, Indonesia or the Philippines.
Interpretation
The proPSMA study did not introduce a new treatment.
It introduced a better way of finding prostate cancer.
For patients, that may sound like a small difference.
However, in real life, it can significantly change a treatment plan.
Better staging can support better decision-making.
Sometimes, this may mean adjusting the radiotherapy field.
In other situations, it may lead to a discussion about additional systemic treatment.
Occasionally, it may change whether the cancer is considered localised or metastatic.
The goal is not simply to find more cancer.
The goal is to understand the disease accurately enough to choose the most appropriate treatment from the beginning.
Overall, PSMA PET prostate cancer staging can help doctors see the disease more clearly and plan treatment more carefully.
Key takeaways
- A normal CT scan does not always mean prostate cancer has not spread
CT scans and bone scans can miss small areas of prostate cancer, especially in high-risk disease. - PSMA PET can show prostate cancer more clearly
When PSMA PET finds cancer that older scans missed, it usually means the newer scan is detecting disease more accurately. - Better imaging can change treatment planning
Finding small areas of cancer may influence radiotherapy, hormone therapy, treatment intensification or clinical trial discussions. - The cancer has not suddenly appeared
The scan has changed, not the biology of the cancer. PSMA PET may simply reveal disease that was already there but not visible on older scans.
References
- Hofman MS, Lawrentschuk N, Francis RJ, et al. Prostate-specific membrane antigen PET-CT in patients with high-risk prostate cancer before curative-intent surgery or radiotherapy: a prospective, randomised, multicentre study. 2020;395(10231):1208-1216. doi:10.1016/S0140-6736(20)30314-7
- European Association of Urology. EAU Guidelines on Prostate Cancer. European Association of Urology; 2026. Accessed June 13, 2026. https://uroweb.org/guidelines/prostate-cancer
Frequently Asked Questions (FAQ)
- My CT and bone scan are normal. Why do I still need a PSMA PET scan?
Because PSMA PET can detect small areas of prostate cancer that conventional scans may miss. - Does a positive PSMA PET mean my cancer is incurable?
Many men with PSMA-detected disease remain candidates for highly effective treatment. - Why do I often have CT, bone scan, and PSMA PET together?
The PSMA PET shows the cancer most accurately, while CT and bone scan help interpret the major clinical trial evidence. - What is the most important number from the proPSMA trial?
A 27% absolute improvement in diagnostic accuracy.
Dr Dilanka De Silva
MBBS, MRCP(UK), MRCP(UK SCE Oncology), FRACP, PhD
Medical Oncologist & Cancer Genetics Physician
Memorial Sloan Kettering Cancer Center Fellow (New York, USA)