The chart that Mal posted is along the lins of what I am thinking, i had remembered reading that before my own dx.
But, if I were you with PC, and he was my dad, I would want him to have a biopsy. The negative DRE is good news, and if his general health is still good for his age, then even he has options no matter what.
Age 57, 56 at DX, PSA 7/7 5.8, 7/8 12.3,9/8 14.5
3rd Biopsy Sept 08: Positive 7 of 7 cores, 40-90%, Gleason 7, 4+3
Open RP surgery 11/14/8, Right nerves spared, 4 days hospital, staples out 11/24/8, 5th cath out on 1/19/9
Pathlogy Report:Gleason 3+4=7, pT2c, 42 grm, tumor 20%, Contained in capsule, one post. margin, clear lymph nodes
2009 PSA 2/9 .05, 5/9 .10, 6/9 .11, 8/11 ?
Lastest 7/13 met with Rad. Oncl, considering options, 7/20 Catheter #6 after complete blockage, scarring closed up bladder neck, corrective laser surgery scheduled for 8/18