Cyberknife how accurate

[Lousantoro]

PSMA than Cyberknife, over 5 days, then 30 days later, no change in PSA, in 90 days then PSA increased, So I paid for another PSMA to compare and found tumor no change in size at its location. Meet this week to ask “ did you miss”.

[GP24]

From what you describe, they must have missed it. The PSA value should decrease significantly and the tumor should be no longer visible on the PSMA scan.

[Lousantoro in reply to GP24]

We agree after time expense and high expectations we were so disappointed . Get to talk with the doctor this Thursday.

[GP24 in reply to Lousantoro]

I got a second Cyberknife radiation when the first did not work well.

[cesces]

It is time to skip local treatment and look at more global treatment.

Do weekly PSA tests. See what the trajectory is.

If there is no trajectory, maybe it is just an anomalous reading.

If it is a trajectory time for a global treatment. It's there, you just don't know where. If you can't see it, you can't hit it with radiation.

Time to move to a new treatment approach. And probably on to a Doc whose primary tool is radiation.

I would not wait to start lining up appointments for second appointments while gathering more PSA info. The second opinions should be with Docs that are Medical Oncologists as opposed to radiation oncologists.

[Quick2019]

I had cyber knife to T-11 in late 2018. It was June 2020 before results of PSMA PET CT showed activity had been reduced by over 50% from before the treatment. My Doctor showed me that the damage to the cells radiated does not kill them immediately. The damaged cells do not reproduce and die on their own over time.

I am not sure PSA test are the best gauge of the work the cyber knife has done.

Best of success with your future treatments!

[MateoBeach]

“Cyber Knife” is such a cool sounding and seductive name for just another method of targeting with X-rays. (Neither a knife nor cyber.)You need to know the targeted tumor volume for each lesion and how many millimeters of margin around the lesion were included in the treatment plan and how many Grey (dose per cubic centimeter of volume) were effectively delivered. Also risk of motion (internal or from breathing etc.), or any positioning sources of error that could have compromised treatment? Do they use cone CT before each treatment to confirm positioning?

If not go elsewhere.

But yes it can’t take a looooonnng time for the Mets to disappear from PSMA scans when they finally get around to dividing and die.

[j-o-h-n]

Hopefully they eventually got the dirty little bastards.........

Good Luck, Good Health and Good Humor.

j-o-h-n Wednesday 01/19/2022 9:26 PM EST

[maley2711]

did they literally " miss".......HIGHLY unlikely IMHO.... I've recently viewed several MD videos in which the ROs mention delayed PSA reduction as impact of radiation can take time for cell deaths. Indeed , could take as long as 2 years for full impact to be seen. Others can answer this..is it more likely that there are simply radioresistant cells ? that would be my guess. Of course , there could also be metastatic sites not seen by PSMA PET, which I've read has maybe 4-5 mm detection minimum... approx 1/5 inch.

Definitely advantage of surgery......... more easily determine success....PSA 0 almost immediately.

[Lousantoro in reply to maley2711]

Compared both PSMA’s, the first 65 days prior to Cyber, the second PSMA four months later, with a side by side comparison. No change in the targeted spot. I have my first scheduled conference call with the Dr today as he is reviewing the images from the provided disc. I want to agree with your assumption; however, no change at this time. I just need to know, so I can move in another direction. I realize there was non absolutes but considering all the hope, time, and expense ( and rising PSA) disappointed. God Bless, be well.