Objectives: The significance of tumor volume (TV) as a predictor of biochemical failure after radical prostatectomy (RP) remains debatable. TV determinants can also entail significant time and cost. Estimating TVs using an asymmetric categorical classification system provides an economical alternative to determining this parameter. We evaluated the prognostic value of an estimated TV in patients undergoing RP in predicting for prostate-specific antigen (PSA) failure.
Methods: We retrospectively reviewed the clinical and pathologic features of 865 patients who underwent RP at our institution from 1991 to 1999. The TV, PSA level, final Gleason score, percentage of positive biopsy cores, and clinical stage were evaluated using univariate and multivariate analysis to determine their association with biochemical failure. Patients were also stratified according to PSA level (less than versus greater than 10 ng/mL), Gleason score (less than versus greater than 7), and clinical T stage (Stage T1c or better versus worse than Stage T1c) to analyze the prognostic significance of TV in this subpopulation of patients.
Results: Of our 865 evaluable patients, 124 (14.3%) had progression to biochemical failure at a mean follow-up of 60 months. The TV was significantly associated with biochemical failure on univariate analysis (P = 0.024). In the low-risk patients (PSA level less than 10 ng/mL, Gleason score less than 7, and clinical Stage T1c or better), a minimal TV was associated with a lower risk of biochemical failure on multivariate analysis (hazard ratio 2.0, 95% confidence interval 1.09 to 3.68, P = 0.025).
Conclusions: In RP patients with favorable clinical and pathologic characteristics, a minimal TV was associated with a decreased risk of biochemical failure. In carefully selected patients, the estimated TV might provide additional prognostic information for risk stratification for PSA progression and biochemical failure.