Extent and zonal distribution of prostatic intraepithelial neoplasia in patients with prostatic carcinoma in Japan: Analysis of whole-mounted prostatectomy specimens

BACKGROUND. Prostatic intraepithelial neoplasia (PIN), an intraluminar prol iferation of epithelial cells in ducts and acini, is divided into high-grad e (HGPIN) and low-grade (LGPIN), based on morphologies. HGPIN is considered to be a putative precursor of prostatic adenocarcinoma (PCA). information on PIN has been limited in Japan, because PIN had not been regarded as a pr ecursor lesion for PCA. METHODS. In this study, extent and zonal distribution of PIN together with its relationship with PCA were examined in totally embedded radical prostat ectomy specimens obtained from 70 patients with PCA. Fifty-three patients r eceived androgen deprivation therapy (castrated) and remaining 17 did not ( noncastrated). RESULTS. Frequency of HGPIN in noncastrated cases (76%) was much higher tha n that in castrated cases (26%) (P < 0.001). LGPIN showed the same tendency , but the difference was smaller. Difference in mean number of HGPIN in non castrated and castrated cases (12.0 and 6.4, respectively) was more marked than in LGPIN (6.4 and 5.1, respectively), Reduction rate of mean size in H GPIN (26%) by the androgen deprivation therapy was larger than in LGPIN. Wh en evaluated in noncastrated cases, the coexistence of PCA and HGPIN was fo und in 76% of cases in the nontransition and 53% in the transition zone. Cl ose association of PCA and PIN (less than or equal to 2 mm distance between lesions) was more frequently found in HGPIN (55% of lesions) than in LGPIN (37%) (P < 0.05). Frequency of close association of HGPIN with PCA was 65% in the nontransition and 35% in transition zone. CONCLUSIONS. The present study from Japan supports the etiological importan ce of HGPIN in the development of PCA. The effect of androgen deprivation t herapy is much more marked in HGPIN than in LGPIN. (C) 2000 Wiley-Liss, Inc .