Posted 9/8/2015 6:40 AM (GMT -5)
A thought to consider: radiation therapy intends to kill the cancer cells but not normal cells. This is done by giving enough radiation to the area of concern to raise the levels of oxidants in the cells. Normal cells have a normal number of mitochondria to neutralize and remove those oxidants. Prostate cancer cells are messed - up and have fewer mitochondria than they would if they were normal, so they are less able to defend themselves against the damage wrought by the radiation. While this generally does not kill the PCa cells immediately, the aim is to kill them more rapidly than they would have otherwise.
In my case the ADT intended to 'freeze' the cancer cell's state and place while the radiation stressed them. As the average life span of a PCa stem cell is about 3 years, the hope is that they are all dead by the end of the therapy. As the cancer cells die, they dump the PSA they contained into your blood stream. If your situation has been accurately perceived and the treatments work as intended, a bunch of those stem cells may die all at once in the target area(s) resulting in a PSA spike.
The effects - both beneficial and side - of the radiation take quite some time to manifest themselves. I am just over 2 years out after radiation therapy and I feel the side - effects every day. Not as bad as they were, but I am aware that the actual window on those is about 3 years and am looking forward to that.