Impact of the extent of extraprostatic extension defined by Epstein's method in patients with negative surgical margins and negative lymph node invasion.

Abstract

To assess the impact of the degree of extraprostatic extension (EPE) on biochemical recurrence (BCR) and utility of the original Epstein's criteria to define EPE in a cohort of pT3aN0 without positive surgical margin (PSM). A two-center retrospective analysis was performed on data from 490 pT3aN0 patients who underwent radical prostatectomy between 2000 and 2012. Patients with neoadjuvant and/or adjuvant therapy, detectable PSA and PSM were excluded. Our pathologists used Epstein's criteria to report the degree of EPE. When pathology reports did not reflect the terms 'focal' or 'established' (non-focal), slides were analyzed by a single genitourinary pathologist for final evaluation. The end point was defined by BCR. Selection criteria yielded 247 patients. Mean follow-up was 56.3±4.6 months; mean age at surgery was 62.5 years. Sixty-one (24.7%) patients experienced BCR during follow-up. Patients with focal extension had a 5-year recurrence-free survival of 89% versus 80% for those with non-focal extension (P=0.0018). In multivariate analysis, both pathologic Gleason score (hazard ratio 2.5; 95% confidence interval 1.4-4.5; P=0.002) and the extent of EPE (hazard ratio 1.8; 95% confidence interval 1.1-3.5; P=0.029) were significant predictors of BCR. The extent of EPE is an independent predictor of BCR in pT3aN0 prostate cancer without PSM. This study reinforces the utility of the subjective Epstein approach already adopted by most pathologists for quantification of the extent of EPE.