Anyone have a view on whether a C-11 scan will be useful in addition to a PSMA PET? My recurrent PSA is low ~0.7. One of my doctors suggested I get both to better assess if/where there may be local activity.
Everything suggests PSMA PET is superior, but I've heard they may be complementary and together can provide a more complete picture. Trial reports that I've tried to interpret suggest odds of about ~85% of accurate assessment in the PSMA PET and only about ~45% on the C-11 scan at my PSA levels (0.5-1.0).
Thoughts?
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PGDuan
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No advantage in getting C11 choline PET scan, or fluciclovine PET. All are surpassed by PSMA scans (Pilarify or Locametz) both with much higher sensitivity in the low PSA recurrence rate.Both are available at your local nuclear medicine department.
Correct, actually the Dana-Farber Cancer center delayed some of my scans, because they haven't received the PSMA Pilarify machine yet. Because the other scan machines would not result into a precise treatment plan.
Then after getting the PSMA Pilarify scans, I got a detailed six weeks radiation treatment execution plan.
I think this is an arguable question at my level of understanding. PSMA based PET is looking at surface marker expression (i.e. PSMA). C11Choline is looking at increased anabolic metabolism. So in theory C11 Choline would detect lesions lacking PSMA expression but having increase metabolism.
What slpdvmmd says is correct, the problem is that your PSA is low and the sensitivity of a choline PET/CT is around 35% or less when the PSA is < 1. Then there is the problem of false negatives since choline pet/ct studies are not specific for prostate cancer.
I would do a PSMA PET/CT first and then according to the PSADT decide if other scan is needed. If your PSADT is very low (<3 months) and the PSMA PET/CT does not show anything then one could discuss if it is indicated to proceed with other imaging technique , choline or FDG for example.
Very few metastases show up on C-11 Choline if they don't show up on Pylarify. In the following study they looked at the same patients with both radioindicators. They found: "Overall detection rate was 75% (27/36) for 68Ga-PSMA and 53% (19/36) for 11C-Choline. Both scans were positive in 18 patients (50%) and negative in 8 patients (22%). Nine patients were positive with 68Ga-PSMA alone (25%) and one with 11C-Choline only (3%)"
My husband had Pylarify as the last patient in Stanford's phase II trial at PSA 1.0 in early December of 2018. F-18 DCFPyL located BCR in the left prostate bed when Axumin, C-11 acetate, and 68 Ga RM2 (also Stanford trial) failed to find it. In mid-January of 2019, still PSA 1.0, Dr. Kwon accepted my husband for C-11 choline + Mayo's MRI. Those two scans supposedly located the BCR in the right prostate bed. Dr. Kwon did have Stanford's imaging for comparison. I say "supposedly" only because we were able to obtain Stanford's imaging but not Mayo's. We knew there was BCR and basically that it was prostate bed so proceeded with treatment and left the difference behind.
Super interesting and helpful! Thanks for sharing. I've shuffled the schedules so will get the F-18 DCFPyL next week and then decide on the C-11 choline (which is out of network for me). Thanks again.
The C-11 was out of network for my husband as well. He would not choose to do it again, especially since Pylarify is available now. I'll stop there, but there is perhaps more than one reason not to need or do both.
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