I recommend this book for all to read...balance approach -- written by a doctor and co-author with PV
"Invasion of the Prostate Snatchers: No More Unnecessary Biopsies, Radical Treatment or Loss of Sexual Potency"
Forgot to say that I think your doctor is right on track and that you should have a biopsy. It's a drag - I know, I've had several, going to have another in a couple of weeks. But the annoyance passes and the knowledge gained can save your life. So my advice is to listen to your doctor. The more samples the better - my last one had 24.
I'm on my third bout with PC - not a doctor, just read a lot and ask questions, so my response here is entirely amateur. 17.2 is a pretty high PSA to not have cancer - but it's entirely possible that your BPH and inflammation alone is causing it. My doctor makes me abstain from sex for a week before testing - you probably know sex raises your PSA for a couple of days afterward. That high-grade PIN is definitely associated with PC at that 35%-rate your doctor mentioned - and still that's a minority of cases, and your free PSA is comforting, but the longer it's been since your biopsy the greater the chance that cancer has developed. This is a good site for all PC matters: http://www.prostate-cancer.org, and this is what the site has to say about PIN: http://www.prostate-cancer.org/education/preclin/pin.html