Ya know...one thing I want to throw out here that I have yet to read here in this Blog is:
How does the doctor know that the remaining prostate tissue producing PSA after prostatectomy and, in this case, after Salvage (or Adjuvant) radiation, is in fact "cancerous" prostate tissue? Ya...has anyone thought that, because a lot of our cancerous prostate also had "healthy/non-cancerous tissue", that "maybe" the source of the PSA that becomes detectable after prostatectomy, and perhaps after radiation, may just be coming from healthy, non-cancerous prostate trying to grow back?
While any follow-up PET Scan or other technology can't detect minute numbers of prostate cells that have taken-up Gallium-68 radioactive tracer, we have to consider the fact that maybe part of that "lack of Gallium-68 uptake" is because the prostate tissue growing and producing PSA, is in fact "healthy" and "non-cancerous" that would not see Gallium-68 uptake.
Our urologists and radiation oncologists seem to defer to the belief that "any detectable and increasing quantities of PSA that occur post-prostatectomy and post-radiation, 'must be' from 'cancerous' surgical margin tissue from what was the cancerous part of the prostate." They assume that when there are surgical margins with the cancerous tissue remaining, that there is no healthy/non-cancerous prostate tissue that also remained in us. They assume that by removing the entire prostate, that they took "all" of the healthy, non-cancerous tissue, and all that remains with surgical margins or as tissue in general, "must be" cancerous tissue. And it is an easy extension from there...a conclusion they take to the bank...that any and all PSA detectable after prostatectomy and radiation "must be" from cancerous tissue that is growing. I am a perfect example: Of my 12-core biopsy samples, three were negative...no cancer detected. If and when my PSA starts to rise in the future, is it possible that some of that health tissue was left in my body, and that it is those cells making the PSA?
I guess in the long run, we are better off for our radiologists to err on the side of caution: "it's likely cancerous tissue making that PSA", than to wait perhaps years to when a PET Scan might be worth repeating with enough tissue to take up the Gallium-68 for detection. But then the question also becomes: Is a "negative" PET Scan a reflection of normal healthy, non-cancerous tissue growing and producing the PSA, or...is it "PET Scan-undetectable" cancerous tissue producing the PSA? They would be lying if they told they can tell the difference, when in fact, they don't know, and can't know.