My fathers' symptoms coincided with rising numbers on his PSA tests. His PSA is regularly checked and he has an inflamed/enlarged prostate which is causing the symptoms. Prostatitis. I have had it as well.
There is more info here, but the point is that prostatitis will show up as raised PSA levels, and while it may not be cancer, it will start causing symptoms as it gets worse and goes untreated by the stagnating patient (couldn't post the direct link so look under prostatitis at this website):
As long as Nick has no symptoms he does not need to worry about treating it, the point is that this is what could be elevating his PSA without him having symptoms yet. If he develops symptoms he can go for the tests outlined in the article above.