[829] Prognostic Significance of Extraprostatic Extension of Prostate Cancer

Daniela Danneman, Fredrik Wiklund, Peter Wiklund, Lars Egevad. Karolinska Institutet, Stockholm, Sweden

Background: Extraprostatic extension (EPE) is a well-established risk factor for recurrence of prostate cancer after radical prostatectomy. The 2009 ISUP consensus conference on handling and staging of radical prostatectomy specimens recommended that the extent of EPE should be reported for stratification of patients in prognostic groups. However, it remains unclear how this should be done. The aim of this study was to stratify EPE based on extent and other characteristics to identify risk groups.
Design: A total of 1156 men underwent radical prostatectomy at the Karolinska Hospital from 1998 to 2005. Men with neoadjuvant treatment or TURP prior to surgery or unavailable histological slides or clinical follow-up were excluded and 1051 cases remained for review. All specimens had been completely embedded. The slides were reviewed. EPE was identified and classified according to extent, localization and presence of perineural invasion (PNI) at EPE. Cox regression models were used to explore association between histopathological features and biochemical recurrence.
Results: EPE was observed in 44.7% of cases (470/1051) and predicted a higher progression rate than that of organ-confined prostate cancer (hazard ratio [HR] 1.4, 95% confidence interval [CI] 1.1 to 1.8; p = 0.007). Focal vs. established EPE according to Epstein (HR 2.0 [1.1-3.5], p = 0.027) and Wheeler (HR 2.2 [1.2-3.9], p = 0.010) and radial distance of EPE (dichotomized by median invasion depth 1.1 mm, HR 1.5 [1.1-2.2], p = 0.015) were all predictive of recurrence (HR 2.0, 2.2 and 1.5, respectively and p = 0.027, 0.010 and 0.015, respectively). A limitation of the Epstein and Wheeler criteria was that they only identified 7.9% and 8.3% of EPE as focal, while dichotomized radial extent split the EPE cases into two equal groups of 50% each. PNI at EPE, circumferential length of EPE, number of sections and foci with EPE and bilateral vs. unilateral EPE showed no significant association with outcome.
Conclusions: Radial extent of EPE predicts recurrence after radical prostatectomy but not circumferential extent, PNI at EPE, number of sections or foci of EPE and laterality. Radial extent can be estimated either by subjective or semiquantitative methods or by measuring invasion depth. The results are useful for the stratification of prostate cancer patients in risk groups after radical prostatectomy.
Category: Genitourinary (including renal tumors)

Tuesday, March 20, 2012 2:30 PM

Platform Session: Section A, Tuesday Afternoon


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