Those of us who start treatment with a PSA of 10 or above (11.1 for me) don't fare as well as those with a lesser read, thus his concern. Like the rest of us, you will have to monitor your PSA with regular blood tests and take appropriate action if it rises.
If it does go up, you will have options in how to deal with it. There is no need of worry if you continue to do your due diligence. Generally speaking, it will take as long to recover from leuprolide acetate chemotherapy as you will have been on it. That means that - if you have been on Lupron for 2.5 years, it will take 2.5 years for it to finally clear your system and stop being effective against the PCa. Meanwhile, you have an opportunity to get as healthy as you can. Your overall health has a major impact on how well you handle treatments and how effective they are. Hope this helps some.