[966] Radial Distance of Extraprostatic Extension Correlates with Biochemical Recurrence after Radical Prostatectomy.

Bianca AMH van Veggel, Inge M van Oort, Alfred J Witjes, Lambertus ALM Kiemeney, Christina A Hulsbergen-van de Kaa. Radboud University Nijmegen Medical Centre, Netherlands

Background: No consensus exists on which method should be used to substage extraprostatic extension (EPE) in prostate cancer. We compared radial distance to other methods, and correlated these to biochemical recurrence (BCR) after radical prostatectomy.
Design: 157 consecutive prostate specimens with EPE were sectioned at 4 mm intervals and completely embedded. The radial distance of EPE was measured by an ocular micrometer. Focal and established EPE were also determined according to the criteria of Epstein and to the criteria of Wheeler. 23 patients with adjuvant therapy or detectable postoperative PSA levels were excluded, leaving 134 patients for BCR analysis. Data were analyzed using Kaplan-Meier survival and Cox regression analyses.
Results: Radial distance ranged from 0.1 to 11.0 mm (median 1.0 mm). Larger radial distance correlated with higher Gleason score (P=0.02) and positive surgical margins (P=0.008). In univariable analysis, maximal radial distance was associated with risk of BCR, as a continuous (P=0.006) and dichotomous (P=0.002) parameter, as were other methods to quantify EPE, such as Epstein's criterion (P = 0.001), Wheeler's criterion (P = 0.004) and total radial distance (P < 0.001). Larger circumferential length of EPE, bilateral versus unilateral EPE and multifocal versus unifocal EPE were not associated with risk of BCR. In multivariable analysis, radial distance dichotomized at one high-power field (0.6 mm) remained strongly correlated with BCR (HR 3.4; 95%CI 1.48 – 7.85; P=0.004). The 5-year risk of BCR was 20% (95%CI: 0.65 – 0.94) in patients with radial distance ≤ 0.6 mm and 47% (95%CI: 0.41 – 0.65) with radial distance > 0.6 mm. Independent predictors of BCR were also Gleason score (P=0.001), positive surgical margins (P=0.005), preoperative PSA (P=0.006), total radial distance (P=0.009) and EPE quantification according to Epstein (P=0.002), and to Wheeler (P=0.004). According to Wheeler's criteria the 5-year risk of BCR was 21% for focal and 43% for established EPE. The additional criterion regarding the limit of focal EPE in no more than 2 slides, gave no better results.
Conclusions: Maximal radial distance dichotomized at one high-power field is a simple and objective method to subdivide EPE and a strong independent predictor for BCR after radical prostatectomy. We recommend to substage pT3a in future TNM classifications according to this parameter.
Category: Genitourinary (including renal tumors)

Tuesday, March 1, 2011 11:45 AM

Platform Session: Section A, Tuesday Morning

 

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