When to consider PET scan imaging and how effective is it?

Posted by tinker @tinker, Mar 25 7:53pm

I was diagnosed with prostate cancer three years ago after having my first PSA test at 58 years old. My MRIs came out negative, and my first biopsy showed a gleason 3+3=6 on one side of my prostate. After watching my PSA continue to rise and having another biopsy, a gleason 3+4=7 was identified, again on one side. At that time my PSA had risen to 6.6 from an initial 5.25. 18 months ago, I opted for cryo -ablation procedure on the entire affected side of my prostate. My PSA dropped somewhat, and then has risen every 3 months since then. I'm now again at 6.0. MRI imaging have shown no clear indication of disease, however, BPH nodules may be contributing to the PSA.
I'm concerned that I have prostate cancer elsewhere, and it seems to make sense to have a PET scan to try and find it. I've been assured that prostate cancer is slow growing, but I'm chomping at the bit to find the reason for the high PSA, and rule out further cancer. I have another biopsy scheduled on my 2 year anniversary of my treatment.
Are PET scans a valid option for someone like me?

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gently | @gently | Mar 26 12:43am

The newer contrast agent has high affinity for PSA. PSMA/PET. Pylarify is the agent approved in 2021. It makes more sense to me that you would have the PSMA/PET before another biopsy. An oncologist would have a good idea if your insurance would cover it. It's fairly expensive around 5 thousand if you have to pay cash.

aldenrobert | @aldenrobert | Mar 26 9:14am

Here is a link to an interesting article that addresses when to consider PSMA PET imaging; https://www.urotoday.com/library-resources/imaging-center/139875-the-current-landscape-of-psma-pet-imaging-in-prostate-cancer-evaluating-men-with-biochemical-recurrence.html
Over the past three years that I have been in treatment for Prostate Cancer I have had 5 or 6 PET/CT scans due to rising PSA post radical prostatectomy and rising PSA post salvage radiation (34 rounds). One year after completing salvage radiation PSA was up to 6.56 and that was when a PET/CT scan did show one metastatic lymph node in my chest. My treatment following that scan was part of the Metacure Study, a combination of two ADT drugs ( Orgovyx and Erleada) for 24 weeks and 5 rounds of radiation to Met. I am now at about 6 months of active surveillance since stopping the drug trial. I have had three consecutive rises in my PSA going from undetectable at the trial end, 16 weeks later PSA 0.02, one month later 0.08, and now two month later PSA is now 1.02 and my most recent PET/CT scan did not shown anything definite. According the the article in the link provided those who have had both Prostatectomy and Salvage Radiation who's; PSA of 1.0 – 1.99 ng/ml: 84% had PSMA PET Positive scan. So even though 84% at a similar stage did show something, in my case nothing definite was seen.

ddun1953 | @ddun1953 | Mar 27 7:06am

I have been 8 months since mine was taken out. Gleason 7 but postsurgery, Lab on prostate and 12 lymph nodes were all clear. 1st BW PSA was .022 and second at .061. If it bumps to .2, then a PSMA Pet Scan and if spots were detected inside where the prostate was Lupron and if spots found outside where the prostate was, Targeted Beam Rad. Doc said I will die very old of something else. Had the CT, Bone and other scans and all clear. I think we all have to accept that this PC will be with us until we die. Just have to mangage it. God Bless.

kujhawk1978 | @kujhawk1978 | Mar 27 7:19am

It does...question may be, what does your insurance company say...?

As to the comment, "I've been assured that prostate cancer is slow growing..." yes, but no. One way to determine your risk is to calculate PSA Doubling (PSADT) and PSA Velocity (PSAV). That, along with clinical data from imaging, your GS and Grade Group will give you more data about your risk. The statement is correct in the sense that you do not have until tomorrow to make a decision and after that..most statistics say 97% of us live five years, the ten year mark data is pretty high too, question is, are you in the 3%...!? With your clinical history, not likely though...

MSKCC has a good nomogram for calculating PSADT and PSAV - https://www.mskcc.org/nomograms/prostate

"In recent years, healthcare providers have realized that the Gleason score might not always be the best way to grade prostate cancer. For instance, not all cancers with a Gleason score of 7 are the same. Cancers with more grade 3 areas (3 + 4 = 7 Gleason score) are less likely to grow and spread than cancers with more grade 4 areas (4 + 3 = 7 Gleason score). Likewise, Gleason score 8 cancers are less likely to grow and spread than cancers with a Gleason score of 9 or 10.

Based on these differences, healthcare providers have started to use a newer system that breaks up prostate cancers into 5 grade groups based on the modified Gleason score groups:

Grade Group 1: Gleason score ≤ 6, or low-grade cancer
Grade Group 2: Gleason score 3 + 4 = 7, or medium-grade cancer
Grade Group 3: Gleason score 4 + 3 = 7, or medium-grade cancer
Grade Group 4: Gleason score 4 + 4 = 8, or high-grade cancer
Grade Group 5: Gleason scores 9 and 10, or high-grade cancer

Unbelievably, some insurances will require you first to have standard MRI and CT before a PSMA PET despite the increased sensitivity, cheaper...

aldenrobert's link is useful and informative.

Talk with your medical team abut the PSMA scan, personally, I would do it, it may inform any treatment, in both cases where I've had imaging done, C11 Choline at May in Jan 17 and Plarify in March 2023, the treatment plan and decision has been informed by the results.

When a urologist refused to consider imaging in late 2016 and would treat based only on PSA, I fired him, went to Mayo, got the C11 Choline scan, glad I did, so was my radiologist, she had something to use in building a plan to treat the whole pelvic lymph nodes, think smart versus dumb bombs.

Kevin