Prognostic significance of histopathological features of extraprostatic extension of prostate cancer

Aims: The 2009 International Society of Urological Pathology consensus conference recommended reporting the extent of extraprostatic extension (EPE) for the prediction of outcome in prostate cancer. Our aim was to stratify EPE into prognostic groups. Methods and results: We reviewed 1051 radical prostatectomy (RP) specimens from 1998 to 2005. EPE was classified according to the extent, laterality and presence of perineural invasion (PNI) at the site of EPE. Cox regression was used to explore associations with biochemical recurrence. EPE was observed in 470 cases (44.7%), and predicted a higher progression rate than for organ-confined cancer [hazard ratio (HR) 1.4, 95% confidence interval (CI) 1.1-1.8, P = 0.007]. Focal versus established EPE according to Epstein (HR 2.0, 95% CI 1.1-3.5, P = 0.027) and Wheeler (HR 2.2, 95% CI 1.2-3.9, P = 0.010), and the radial distance of EPE dichotomized by the median (1.1 mm) (HR 1.5, 95% CI 1.1-2.2, P = 0.015), were all predictive of recurrence; but PNI at the site of EPE, circumferential length of EPE, number of sections and foci with EPE, and bilateral versus unilateral EPE were not. Conclusions: The radial extent of EPE predicts recurrence after RP, but circumferential extent, PNI at the site of EPE, number of sections or foci of EPE, and laterality do not. If validated, the proposed radial extent method may allow for more reproducible quantitation of EPE.