Serum prostate-specific antigen value adjusted for non-cancerous prostate tissue volume in patients undergoing radical prostatectomy: a new predictor of biochemical recurrence in localized or locally advanced prostate cancer

The aim of this study was to investigate the significance of serum prostate-specific antigen (PSA) value adjusted for total tumor volume (PSA/tumor volume) and serum PSA value adjusted for non-cancerous prostate tissue volume (NCPV) (PSA/NCPV) as a predictor of pathological findings and clinical outcome after radical prostatectomy. Clinical and pathological data of 407 patients (median age: 66.5 years; range: 41.8-85.7 years) were reviewed retrospectively. The median follow-up period was 18.1 months (range: 1.0-107.8 months). Biochemical recurrence was defined as detectable PSA levels (greater than 0.2 ng ml(-1)) and the time of biochemical recurrence was taken to be the first time PSA became detectable. In the multivariate model, PSA/NCPV was an independent predictor of extracapsular extension and positive surgical margin (P<0.05), but PSA/tumor volume was not. Kaplan-Meier curves revealed that PSA/NCPV correlated with biochemical recurrence-free survival (P<0.001; log-rank test) but PSA/tumor volume did not (P=0.275; log-rank test). PSA/NCPV was also a significant independent prognostic factor for biochemical recurrence-free survival on multivariate Cox proportional hazard analysis (P=0.004, relative risk=2.42). Our findings suggest that PSA/NCPV is associated independently with extracapsular extension and surgical margin status and may be an independent prognostic variable of PSA recurrence after radical prostatectomy.