Prevalence and distribution of prostatic intraepithelial neoplasia in salvage radical prostatectomy specimens after radiation therapy

High-grade prostatic intraepithelial neoplasia (PIN) is the most likely pre cursor of prostate cancer. The effect of radiation therapy (RT) on the prev alence of PIN is uncertain. We studied 86 patients who underwent salvage ra dical prostatectomy after irradiation failure at the Mayo Clinic. The preva lence, volume, multicentricity, spatial proximity to cancer, and architectu ral patterns of PIN were evaluated. High-grade PIN was identified in 53 (62 %) of 86 prostatectomy specimens. Multiple architectural patterns were usua lly observed, including tufting in 81%, micropapillary in 66%, cribriform i n 38%, and flat in 17%. The mean volume of PIN was 0.12 cm(3) (range, 0.05- 1.20 cm(3)). PIN was usually multicentric (70%), with a mean number of PIN foci of 2.5 (range, 1-10). Ninety-four percent of PIN foci were located wit hin 2 mm of invasive cancer. There was no correlation between PIN and patho logic stage, surgical margin, tumor size, DNA ploidy, post-RT Gleason score , time interval from RT to biopsy-proven recurrence, postoperative prostate specific antigen level, distant metastasis-free survival, or cancer-specif ic survival. Our examination of salvage radical prostatectomy specimens ind icated that the prevalence and extent of PIN appeared to be reduced after R T compared to published studies of prostatectomies without prior RT.