Ga-68 PSMA PET/CT Imaging Issues

I stumbled across this page/video, PSMA PET/CT- Struggling with Increased Sensitivity, of a presentation about bringing Ga 68 PSMA PET/CT imaging online from the Society of Nuclear Medicine and Molecular Imaging (SNMMI) Annual Meeting. It’s definitely worth the 23 minutes to watch it if you have any interest in imaging for prostate cancer.

Ga 68 PSMA PET/CT scans definitely can see much more than current imaging technologies and is fast becoming the new “gold standard” of prostate cancer imaging. But, as with anything new, there are things we have to understand to use the technology to its full advantage and to not misinterpret what it’s telling us.

One of the statements in the presentation that struck me was, “Just because you can see it, doesn’t mean you should treat it.” The presenter described the following scenario:

“So this is a patient who’s eight years after a prostatectomy with rising PSA and when the gallium PSMA PET scan is done, we see focal intense uptake in a solitary mesorectal node, which measures two to three millimeters and we’re really seeing micro metastatic disease. And I think the title of the slide is just because you can see it, doesn’t mean you should treat it because we don’t know how long that lymph nodes been there for. This is not in the classical nodal dissection. This lymph node could have been there five years ago and maybe it hasn’t changed and we don’t know that. So it’s easy now to say let’s cut it out because we can see it or let’s give it stereotactic radiotherapy, but I look at an image like this and think if it’s taken eight years for this lymph node to get to two to three millimeters, this is extremely indolent disease and perhaps it’s best left alone.”

He also talked about early interventions taken as a result of the PSMA PET/CT scans that may have caused more problems for the patient than necessary without changing the outcome (i.e., continued recurrence after the procedure).

Again, I found this to be very enlightening as I’m heading into my appointment this week and considering going to UCLA for their PSMA trial.

 

PSMA-SRT Randomized Phase 3 Trial is now open at UCLA

Every now and again I’m asked to share information on my blog, and this was something that is of personal interest to me given my current situation. It’s from the UCLA Nuclear Medicine department and will likely be of interest to others as well.

They reference a couple of attachments in their email to me, but none were attached.


We have the pleasure to announce the opening of a Randomized Prospective phase 3 trial of PSMA PET/CT based salvage radiation therapy (PSMA-SRT) at UCLA Nuclear Medicine (NCT03582774).

https://clinicaltrials.gov/ct2/show/NCT03582774

This is the first randomized prospective phase 3 trial designed to determine whether PSMA PET/CT can improve outcomes in patients with prostate cancer biochemical recurrence.

PSMA PET/CT will be free of charge for patients (100% sponsored by UCLA Nuclear Medicine).

Patients who are planned for salvage radiation therapy (SRT) for recurrence after primary prostatectomy with PSA ≥ 0.1 ng/ml are candidate.

We will randomize patients to proceed with standard SRT (control arm 1) or undergo a PSMA PET/CT scan prior SRT planning (investigational arm 2).

Patients randomized to control arm 1 will not undergo PSMA PET/CT: SRT will be performed as routinely planned per discretion of the treating radiation oncologist. Any other imaging will be allowed for SRT planning if done per routine care.

Patients assigned to arm 2 will be scheduled to undergo a PSMA PET/CT scan at UCLA Nuclear Medicine (free of charge) prior to radiation therapy planning. DICOM images and reports of PSMA PET/CT scans will be delivered to the treating radiation oncologist.

The radiation oncologist may change the radiation plan depending on the findings of the PSMA PET/CT scan. That is, the treating radiation oncologist may use whatever dose, fractionation, and target volumes they choose, and may use concurrent ADT or not, at their discretion (please see the attached document for the radiation therapy management specifications).

The primary endpoint of the trial is the success rate of SRT measured as 5-year biochemical progression-free survival after initiation of SRT.

Patients will be followed by the UCLA Nuclear medicine research team for up to 5 years after initiation of SRT (phone/fax/secure emails with the treating radiation oncologist team and/or with the patient) every 3-6 months (routine PSA and imaging).

To enroll a patient:

  • All subjects must sign the UCLA IRB approved informed consent form (ICF, attached) before enrollment and randomization.
  • For UCLA patients, this will be done after a consultation with the UCLA Nuclear Medicine Team or the UCLA Radiation Oncology Team.
  • For all other patients outside of UCLA, this will be done after a phone consultation with the UCLA nuclear medicine research team. Signed ICF will then be obtained by fax or email.
  • The randomization number and assigned arm will be communicated by phone or email to treating physicians and patients one day after the enrollment.
  • Patients randomized to control arm 1 will not need to come at UCLA and will receive SRT per routine care at the treating radiation oncologist institution.

This trial represents a good opportunity for all the patients who cannot afford the out-of-pocket costs of a research PSMA PET/CT (at UCLA: around $2700).

Please try to spread the word as much as you can around you.

In advance I thank you very much for your collaboration.

Please don’t hesitate to contact us if you have any question:

Jeaninne Gartmann, Study Coordinator: JGartmann@mednet.ucla.edu
Jeremie Calais, Principal Investigator: JCalais@mednet.ucla.edu
Nicholas Nickols, Co-Principal Investigator: NNickols@mednet.ucla.edu

Best regards

Jeremie Calais MD MSc
Assistant Professor
UCLA Nuclear Medicine