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Finished radiation therapy, how will I know if it worked

Posts: 102
Joined: Jan 2012

My husband finished IMRT on May 14th is also on HT. We wanted to know what happens next, expecting some sort of a test to determine the results. The oncologist said that the urologist (appt on June14th) would probably take a psa 3 months down the line then we would have an idea of how well it worked. He said a PSA test in one months time might show a false psa since he's on HT. (I think I have that statement right)
Is this true, do we really have to wait 3 months to know how it's worked. It's scary not knowing whats' going on. I realize what an understatement I have just made, but nonetheless, I'm sure you can all relate.
Thank....s any light you can shed would be appreciated.

Kongo's picture
Posts: 1167
Joined: Mar 2010


After radiation treatment all the cancer cells don't die at once. Radiation damages the DNA so that the cells cannot go through mitosis and continue to expand. Since cancer cells are fairly slow growing and they all started growing at different times they will be attempting to divide at different times. Also, sometimes it takes a generation or two of cells before the damage to the DNA takes effect and the cells die. So, what you get is a gradual decrease in the PSA reading over time until you reach a nadir, or low point, which is a consistent and stable low level, generally below 1 ng/ml. It can take a couple of years to reach nadir.

There is also a phenomenon known as a "PSA bounce" where after some decline, there is a spike upward and then continues on a downward trend toward nadir. They don't really know what causes a PSA bounce but it happens to about a third of all men who undergo radiation treatment. Just something to keep in mind.

When you are also on HT it's impossible to tell if the low PSA levels are a result of the radiation or the HT which is depriving the cancer cells of the testosterone they need to grow. Once you go off HT and testosterone levels return to normal then they can begin to assess the effect of the radiation treatment by tracking the decline in PSA levels over time.

You should continue to monitor PSA levels on a regular basis. After you reach nadir, the doctor will probably want to have it checked every six months or so. If the PSA should start to rise above nadir it could be an indication of a recurrence. After radiation, a recurrence is usually defined as a 3 or more PSA rises and a level that is 2.0 ng/ml above what your nadir was. So, for example, if your nadir was 0.5 ng/ml and your PSA rose three consecutive times and the third time was say 2.8, then you would be considered to have had a recurrence and may wish to restart HT.

Hope this helps.


Posts: 195
Joined: Aug 2006

This is our world, one with few knowns. We lived much of life comfortable in the (false) knowledge that we rule our life. Now we know that to be false.
If Mr. D is on androgen reducing therapy, which I assume he is, then any psa will be affected by that first. The results of the radiation will be unknown until some months after the hormone reducing medication leaves the body, which may be some time in the future. I can tell you that the radiation worked. Whatever else is involved, the radiation certainly did, and does, what it should, and for some months or years to come. Kongo addressed that. Is it sufficient? Re-read my first sentence.
My partner assumes the best. It is a kind of denial, but for healthful reasons. It improves her life and gives her the sense that all is well. There is no reason her quality of life should be impacted by my treatments and prognosis. It also prevents me from having to deal with her anxiety, as well as that of my own. It works for her, and for us. I can lay awake at night and wonder about what is happening to my cells; she can sleep secure.

Posts: 102
Joined: Jan 2012

Thanks so much for your replies. I guess all we can do is wait and see ! Good to have such a wonderful place as this to get information,
Will post updates
God bless

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