Risk stratification after radical prostatectomy in men with pathologically organ-confined prostate cancer using volume-weighted mean nuclear volume

Abstract

We examined the impact of volume-weighted mean nuclear volume (MNV) on biochemical failure after radical prostatectomy (RP) in pathologically organ-confined prostate cancer (PC) and developed a prognostic factor-based stratification model for these patients. We analyzed 141 patients with pathologically organ-confined PC treated solely with RP. Unbiased estimates of MNV were calculated from biopsy specimens based on a stereological method, and compared with other clinical and pathologic findings including patient age, pre-treatment PSA, biopsy and RP specimen Gleason score, pathologic stage, total cancer volume, index cancer volume, tumor differentiation, number of tumor foci, main tumor location, and surgical margin status, with regard to prediction of disease outcome after RP using Cox proportional hazard models. The median follow-up was 38.6 months (range 4--119 months). Twenty patients (14.2%) experienced biochemical failure. On multivariate analysis, MNV was demonstrated to be an independent prognostic factor, along with pre-treatment PSA and total cancer volume (P=0.0004, 0.0184, and 0.0285, respectively). All patients were stratified into three groups according to their prognostic scores developed on the basis of multivariate analysis, with statistically significant prognostic differences revealed for each of the between-group comparisons. The results demonstrated that estimates of MNV contribute most significantly to the prediction of biochemical control of pathologically organ-confined PC. The combination of MNV with other independent predictors such as pre-treatment PSA and total cancer volume provided a statistically verifiable basis for risk stratification, facilitating more accurate prediction of disease outcome.