My husband had proton therapy about four years ago. His PSA has continually gone down from 11 at diagnosis to a 3.08 now. His dr did a biopsy and found some questionable cells. Several weeks later he took another biopsy and no cancer cells were found. He had a scan after isotopes were administered, and no cancer cells were found. The dr now wants to do a PET scan, because he said when a person has 3.0 or greater PSA, there is a 95% chance there is cancer somewhere in the body. Do any of you know anything about this? Is it true?
I would really appreciate any light you could shed on this.
I'm sorry to hear that 4 years after proton therapy his PSA has only gotten as low as 3.1. I'm assuming he had a Gleason 6 (3+3) or 7 (3+4) score to begin with, because proton monotherapy would be very unusual with higher scores. I'm also assuming that the biopsy did not show signs of hyperplasia or prostatitis that would account for the PSA.What was his PSA history after therapy -- did it plateau at around 3 or did it get to a lower value and then increase to 3? It matters.
Assuming it plateaued and never increased, the most likely scenario is that there is a hypoxic area somewhere in the prostate. Hypoxia -- low oxygen -- can occur in the thick tissue surrounding a tumor. Good oxygenation is necessary for the protons to kill the cancer cancer cells, and cancer cells can survive in hypoxic areas. The biopsy is just a sampling of cells in different places and a 12 core biopsy can easily miss the hypoxic areas where the cancer cells survive. If that is the case, you can do one of two things:
Continue to biopsy, perhaps doing a saturation biopsy until you find the hypoxic and cancerous tissue. Then you can treat just that area with SBRT or HDR brachytherapy. Or,
Continue to monitor PSA periodically. If the PSA never increases, the cancer may be indolent, and may never be a further cause of concern.
Unfortunately, proton therapy delivers a lifetime maximum dose of radiation to the prostate and a margin around it, so you can't re-treat the whole local area; however, if it is possible to locate the cancer in the prostate, the prostate bed or lymph nodes, you can spot treat just that place with SBRT or HDR brachytherapy.
When you wrote "he had a scan after isotopes were administered," wasn't that a PET scan, or was that a contrast MRI? There are several types of PET scans, but I do not know if they would show anything with a PSA of just 3. An ordinary bone scan is much too insensitive for very small tumors, but one of the newer ones like Prostascint, F18Choline, or NaF18 (there are a few others that are not commonly available) may be worthwhile. If you have access to the Mayo clinic, or a handful of other specialty places, you may be able to get a C11Choline PET scan, which is much more sensitive. Feraheme MRI is in clinical trial at SandLake Imaging in FL, but I have no idea if it can pick up anything in and around a proton-radiated prostate. I don't know if they've had any experience with that, but you can call.
If his PSA has been rising and you can't locate it in the local area, it is possible that it has metastasized. In that case, hormone therapy may be required to slow its spread.
I'm hoping that it is just some indolent cancer in a hypoxic area that only needs watching.
Thank you for your reply.
His Gleason score was a 6 (3+3). He doesn't know if he had hyperplasia or prostatitis. They didn't prescribe antibiotics, so I am guessing he didn't have prostatitis. They saw something unusual in the first biopsy (second biopsy if I count the one before treatment) because they did another one. They took 25 samples and found no cancer cells in them. After therapy, his PSA count was between the 2's and 3's and now is at 3.08.
What are a saturation biopsy, SBRT and HDR brachytherapy?
I am assuming he had an MRI with isotope administration, because the dr now wants to do a PET scan. (My husband is phoning them and find these things out.)
He had his proton therapy at Loma Linda and that is where his doctor is (He had Dr. Rossi for the proton treatment and followup,but he is now totally into research I believe, and Jim now has Dr. Baldwin in the urology department.)
Thank you so much for your reply. I welcome any additional information you may have.
It sounds like he already had a saturation biopsy when they took 25 cores. So the next place to look for it is in the prostate bed. Perhaps one of the imaging techniques will locate it. If you're in Southern California, you might want to contact the major teaching hospitals like USC or UCLA (or UCSF if you're up North) to inquire about the imaging.
HDR (High Dose Rate) brachytherapy and SBRT (Stereotactic Body Radiation Therapy, often known as CyberKnife) are highly precise ways of applying radiation to the prostate bed to any desired depth. They are highly concentrated forms of radiation that do a better job at killing prostate cancer cells than other forms of radiation like protons and IMRT, and do it with fewer side effects. I don't think Loma Linda does either. Dr Fuller in San Diego does salvage SBRT, and I think that Dr Demanes at UCLA does salvage HDR brachy. You may want to call to check. There are many other radiation oncologists in Southern California who may do them, but those are the ones I'm familiar with.
My feeling would be to go to a different doctor and institution for salvage than you did for initial treatment. The original doctor/institution might be trying to hide their mistakes.
Could be a very slow cancer cell kill - the PC cells don't die until they try to reproduce. Maybe he's still bouncing -- I would've thought 4 yrs is long enough. Has his radiation oncologist seen cases take this long to achieve nadir with protons? Or it could be some prostatitis. If it were me, I'd want to just keep monitoring it, maybe try some antibiotics and some Celebrex or an NSAID -- it may yet settle down. At any rate, when PSA goes down, it's a good thing.
Bounces are very common with all forms of radiation and is part of the curing process. Four years is a long time to bounce, usually it settles down by then. See my post #7 above for possible explanations.
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