The "flare" is a spike in tesosterone after the injection. It begins almost immediately and causes a mans testosterone to spike approximately 65% above your normal level. If your level was 400 it would rise to approximately 650 in theroy causing your PCa to worsen. The big reason for the Casodex is for guys with advanced PCa, mets and such, to not cause the disease to worsen. The spike itself lasts approximately 5-7 days and begins to receed. Most individual's tesosterone is back to normal in 14 days and headed down to a nadir which occurs anywhere from 28-65 days after injection.
The interesting thing was the PSA didn't follow the testosterone spike, I guess because it was for such a short time the PSA couldn't catch up before the tesosterone started down again.
For guys with little to no disease to begin with some Doc's don't believe it necessary, I went ahead and did the Casodex thing because it was easy and took any chance of "flare" out of the equation.
Fairwind, I don't believe there are any experts on this board just guys with experience they would like to pass on.
I received this information from a study that I have tried to post here a few times but for some reason it won't allow me to do it. I'm not the most computer literate guy.