Prostate cancer at the peripheral end of prostate biopsy specimen predicts increased risk of positive resection margin after radical prostatectomy: results of a prospective multi-institutional study.

Purpose: To test a novel technique of processing prostate biopsy specimen by marking the peripheral end (PE) as a predictive tool for positive resection margin after radical prostatectomy (RP) or for locally advanced carcinoma of the prostate (PC).

Methods: Prospective, multi-institutional study of a consecutive cohort of men who underwent prostate biopsy with marking the peripheral biopsy end and subsequent RP at the same institution.

Results: The study cohort comprised 445 men with a mean age of 63 years (40-77 years). Overall, PE-positive cores were found in 174 men (39.1 %) and R1 status was diagnosed in 132 men after RP (29.7 %). In the multivariate analysis, the presence of at least one PE-positive core was correlated with an increased risk of R1 status (OR 2.29, 95 % CI 1.31-4.00, p = 0.003) and was the strongest predictor followed by Gleason score, PSA and percentage of positive cores. Including all predictive parameters, a nomogram with a concordance index of 72.1 % was calculated. In the pT3/pT4 subgroup, PE positivity was the only predictive factor for R1 status (OR 3.03, 95 % CI 1.36-6.75, p = 0.006). In pT2 stage, no single factor was predictive for R1 status. PE-positive biopsies were not predictive for pT3/pT4 stages.

Conclusions: PC at the peripheral end of prostate biopsy specimen predicts an increased risk of R1 status in subsequent RP. This simple and cheap technique may contribute to an increased accuracy of risk stratification for curative treatment for PC.