BACKGROUND: Early detection of small volume prostate cancer (PCa) has led to the concept of focal therapy to treat in an organ-sparing manner. We evaluated trends in pathologic staging among patients with localized PCa undergoing radical prostatectomy (RP), defining the frequency of unilateral cancers during 1988-1995, 1996-2000 and 2001-2006. METHODS: Data were abstracted from the Duke Prostate Cancer Outcome database selecting 3,676 men with available pathology treated with RP. Based on surgical pathology, trends in as pathological T (pT) stage, pathological Gleason Score (pGS), and percent tumor involvement (PTI) were evaluated. RESULTS: pT2a increased from 2.8% of men undergoing RP in 1988-1995 to 13.0% during 2001-2006 (P < 0.0005). PTI analysis shifted towards low volume disease, e.g. PTI