I think you can wait without too much worry. Your PSA at around 10 is elevated but mine was around 12 or so for 3 years and I only took action when the PSA went to 18. I did just finish proton therapy and pretty happy with the outcome.

At 72, you could probably let it run wild (read no treatment) and still live to 90.

Once you are on forums and such however, your ability to wait and see will be tested. The data says do nothing for a while and see where we are in a year or two. Humans on message boards have you getting all sorts of things done to you which in all likelihood is rather harmful.

Your call.