Improving PSMA PET scan accuracy to pinpoint recurrent cancers

By Rhys Leeming and Mish Middelmann

For anybody whose prostate cancer is beginning to come back, a huge challenge is knowing it’s back but not knowing exactly where it is. In this post we are sharing some exciting news that might increase PSMA PET scan accuracy (pinpointing the location of resurgent cancer cells) by up to 16 times. If you can find the cells you can blast them with radiation before they multiply further.

Typically the first sign of biochemical recurrence after initial treatment is that your PSA begins to rise. But PSA is a blood test and doesn’t tell you where the cancer cells are. PSMA PET scans aim to find the proverbial needle in the haystack. Current technology can draw a blank on this search, in the experience of some RecoveringMan readers.

Rhys has been selected for a clinical trial in Sydney, Australia that compares a new copper-based radioactive marker (Cu-PSMA) with the conventional gallium-based (Ga-PSMA) marker. Early indications are that the new Cu-PSMA marker could enable more than ten times the accuracy.

Nothing in this post should be taken as medical advice. We’re telling the story for information purposes and if any of it seems relevant to you, please discuss it with your doctor.

Why PSMA-PET scan accuracy matters

If your PSA goes up after radical prostatectomy, you know the cancer is coming back, known as biochemical recurrence. If you can’t pinpoint the location where cancer cells are proliferating, though, treatment becomes difficult. Some people end up getting treatment using external beam radiation that can feel a bit like a scatter-gun approach.

Without accurate location of the location of the cancer’s return, the typical treatment is radiation of the prostate bed. That’s beaming the radiation into the entire area where your prostate used to be. But there can be more collateral damage with this approach. It might also miss the cancer completely – sometimes the prostate cancer recurrence is located elsewhere in the body.

With increased sensitivity, new PSMA-PET scans would have a better chance of locating the new cancer cells in your body. Then there are excellent techniques for highly targeted radiation only targeting that specific location. You can therefore expect more damage to the cancer cells and less to the rest of your body.

How the new copper PSMA tests might help

The attractive difference between the new Cu-PSMA and the old Ga-PSMA markers for PET scans is that the copper based markers remain active for considerably longer. Logistically, this means these specialised marker materials can be shipped to more remote areas for testing without losing their potency.

The longer active life of Cu-PSMA also enables important changes to your scans. Its relative longevity means the actual scanning process can go on for longer. There are indications that even better results occur if you inject the markers and then wait 24 hours or more before doing the scan.

Rhys’s story

Here are some of Rhys’s Facebook Sex, Love and Prostate Cancer group posts as the story unfolded.

April 9, 2025: I joined the approximately 40% of post prostatectomy guys to have my PSA start to rise back in April 2022. It’s taken 3 years but I’ve now busted through the 0.2 barrier and sit at 0.26. I’m very lucky really with a slow doubling time and good post operative pathology. So I just had a call with my oncologist who has put me in a brand new imaging trial at St Vincent’s hospital Sydney.

It’s a comparison between existing PMSA Pet Scans and a new copper based radiological protein dye (using PMSA techniques) that promises 16X more sensitivity. Hopefully this means a better chance at seeing where the little alien is hiding, at lower PSA levels and in difficult terrain, thereby allowing a more stereotactic approach to prostate bed therapies.

Rhys says “Anyone else in this situation; check with your oncologist and see if you too can access some of the new technologies coming out. Remember, prostate cancer might be pretty shit, but there’s lots of worse things out there. I for one consider myself lucky.”

May 1st, 2025: Later this month I’m taking part in this PMSA Pet Scan trial in Sydney at St Vincent’s hospital. May 20-22. Three scans over three days comparing gallium versus copper isotopes. Here’s hoping they find where the little alien is hiding. Trials are underway in the US after being fast-tracked by the FDA.

You might be eligible for these trials

Initial evaluation of the new methods have been encouraging, according to this April 2025 report. Here are details of the US trial which is currently recruiting. But remember, we’re not the doctors. If interested, you will need to explore this further with your doctor.