Hi, JP and welcome to the forum.
Trust you are receiving professional advice about Prostatitis. It's not unusual for men of your age to have a least the start of some cancer which may or may not develop at a slow or moderate pace or not at all. A lot depends on the type of cancer you have, where it is precisely and how it mutates. You have not given much detailed information of your diagnosis but from what you say cancer seems to have been found at an early stage, so you can be monitored and offered treatment at an appropriate time.