psa drop after radiation?

Psa should drop, if in fact, the rise was indeed caused by the mets in question. Not always the case. Yes there is a direct relationship between Pca cells and Psa. You may or may not know that some variants of Pca cells release no Prostate specific antigens.

Some prostate cancer variants throw off a lot of PSA, some much less. Kill off the second type, and you reduce the PCa cell load, but don't change the PSA by much.

However, if spots of PCa are treated, PSA should go down some in time as a result. But it is important to remember that the RT does not immediately kill the cells, it simply renders them unable to reproduce. That is why there can actually be PSA increases after RT, as the cells are irritated, but not yet dead. PSA falls off over time, as they die off and are not replaced

In spot radiation, the dose would be much higher, and may cause the cells to die off faster. You would need to discuss your specific case with the radiation oncologist to get a perspective on what you should expect.

Tall Allen said...
Are you talking about palliative radiation of bone mets where the cancer has become castration resistant? If so, I don't think you will see much of a drop in PSA. You may see a drop in alkaline phosphatase levels, however. The goal is pain relief, rather than PSA reduction.

- Allen

This spring they found a spot near the spinal cord, so they started RT to prevent spinal cord compression. However, the PSA or ALP didn't increase before they found the spot so the doctors thought it might was dead cells lumped together, but they started RT just in case. He didn't have any pain either. MRI after 3 months showed no change, also the PSA and ALP was the same as before RT, and the doctors concluded that it was no new mets, but only old dead cancer cells. My father had no pain before RT either, he's been in very good shape the last years, and his PSA was 60 before RT. (He started RT in april, now his PSA is still 60). I'm just afraid that the doctors have made the wrong conclusion, and that it actually was new cancer cells near the spinal cord.

Tall Allen said...
There are micrometastases and circulating tumor cells putting out PSA, and the amount of PSA from a single met may be overshadowed by that. What difference would it make in his treatment either way if that spinal bone met were active or dormant when they zapped it? I'm sure they will periodically monitor for new bone mets and zap them or give him Xofigo if detected. Xgeva may slow them down and prevent skeletal-related events.

Because if it was dead cells it wasn't any new met at all. (dormant are just inactive pca cells right? But dead cells aren't pca cells at all? At least this is how I've perceived it)

I see, but as I perceived it they didn't thought this new spot was a met, but dead cancer cells (from other mets) lumped together so it seemed like a new met on MRI. They said that sometimes that happened.

I also just read an article that sais:" CT or MRI may not always distinguish between scar tissue after surgery, dead cancer cells after treatment with chemotherapy or radiotherapy, an infection or a tumor, says chief physician Magne Aas at the nuclear medicine department at the Norwegian Radium Hospital (DNR)."

You can read it here: http://tux1.aftenposten.no/nyheter/iriks/d98805.htm
It's in norwegian though, but try to translate it in Google translate

That may be right, but on all other successfull treatments he's har (hormone treatment, chemo, zytiga) his PSA has decreased a lot. And he didn't start RT because of pain, but because they thought there was a tumor lying close to The spinal cord, which they needed to get control over. However now they've changed their mind and think It's only a lump of dead cells