@marko49
If someone is brand new to Prostate cancer then ADT can make a major difference in their PSA. If someone has a 3+4 with a low percentage of cancer than ADT might may not help that much. Getting treated with radiation or surgery could eliminate the need to use it.

The studies that discuss the effectiveness of ADT talk about having an Extensive time of ADT when there is not a serious prostate cancer case.

If there is a very aggressive case and 2 to 3 years can be sensible.

There are also issues with taking it for a very long time, Becoming resistant to it, can become a big problem. If somebody has been undetectable for a couple of years, they can try stopping it even if they have an aggressive case. You just need to watch it carefully, Doing regular PSA test to make sure it doesn’t come back

Studies that talk about The effectiveness of ADT discuss all those issues.