Quantification of extraprostatic extension in prostate cancer: different parameters correlated to biochemical recurrence after radical prostatectomy

Abstract

Aims: Different methods to substage extraprostatic extension (EPE) were correlated with biochemical recurrence (BCR) after radical prostatectomy (RP).

Methods and results: A total of 157 consecutive RP specimens with EPE were completely embedded. Twenty-three patients with adjuvant therapy or detectable postoperative PSA levels were excluded, leaving 134 patients for BCR analysis. Data were analysed using Kaplan-Meier survival and Cox regression analyses. In univariate analysis, maximal radial distance (RD) was associated with BCR as continuous (P = 0.006) and dichotomous (P = 0.002) parameters. In multivariate analysis, independent predictors of BCR were preoperative prostate-specific antigen (PSA) (P = 0.006), Gleason score (P = 0.001), positive surgical margins (P = 0.005), maximal RD dichotomized at 0.6 mm [= one high-power field (HPF)]; hazard ratio (HR) 3.4; 95% confidence interval (CI) 1.48-7.85; P = 0.004), total RD (P = 0.009) and EPE quantification according to Epstein (P = 0.002) and to Wheeler (P = 0.004). The 5-year risk of BCR was 20% (95% CI 0.65-0.94) in patients with RD ≤ 0.6 mm and 47% (95% CI: 0.41-0.65) with RD > 0.6 mm. The restriction of focal EPE in no more than two slides (Epstein and Wheeler) gave no better results.

Conclusions: Maximal RD dichotomized at one HPF is an objective method to subdivide EPE and a strong, independent predictor for BCR after RP. Its use is recommended for substaging pT3a in future TNM classifications.