Clinically significant and insignificant prostate cancer following prostate intraepithelial neoplasia

Aim: To investigate the rate of clinical significant and insignificant Prostate Cancer (PC) in patients with initial high grade and low grade Prostatic Intraepithelial Neoplasia (PIN).

Materials and Methods: The study included 286 patients with PIN, 152 patients with HGPIN and 134 patients with LGPIN. During 3 year follow-up prostate rebiopsies with 6 months interval were performed. Each PC case was assessed in relation to its clinical significance according to such Epstein criteria as PSA density < 0,15, Gleason score < 7, number of cores positive for tumour < 3, no more than 50% involvement by tumour in every single core.

Results: During 3-year follow-up in 75 (26,2%) of 286 patients with PIN was detected PC (64 (42,1%) patients with HGPIN and in 11 (8,2%) patients with LGPIN). General estimation of clinical insignificant PC cases that were detected in patients with prior PIN amounted 12 (16%) patients. The majority of patients, namely 63 (84%) had clinical significant PC. Among 11 PC cases in patients with LGPIN 4 (36,4%) cases were insignificant. The rate of insignificant PC in HGPIN was 8 (12,5%). Statistically valid difference between HGPIN and LGPIN in rate of insignificant PC, that was 23,9% was determined.

Conclusions: PIN is a cancer precursor that progresses into PC in 26,2% of cases during 3-year follow-up. The rate of clinically insignificant PC in patients with PIN was in 23,9% more in patients witn LGPIN than in patients with HGPIN.