Prostate Size as a Predictor of Gleason Score Upgrading in Patients With Low Risk Prostate Cancer

Purpose: Gleason score upgrading between biopsy and surgical pathological specimens occurs in 30% to 50% of cases. Predicting upgrading in men with low risk prostate cancer may be particularly important since high grade disease influences management decisions and impacts prognosis. We determined whether prostate size predicts Gleason score upgrading in patients with low risk prostate cancer. Materials and Methods: A total of 1,251 consecutive patients with D'Amico low risk disease and complete data available underwent radical prostatectomy at our institution between January 2000 and June 2008. Patients were divided into 3 groups by pathological Gleason score, including no, minor (3 + 4 = 7) and major (4 + 3 = 7 or greater) Gleason score upgrading. We developed bivariate and multivariate models to determine whether prostate size was an important predictor of upgrading while controlling for clinical and biopsy characteristics. Results: Of 1,251 cases 387 (31.0%) were upgraded, including 324 (26%) and 63 (5%) with minor and major upgrading, respectively. As expected, Gleason score upgrading was associated with worse pathological and cancer control outcomes. On multivariate analysis smaller prostate size was an independent predictor of any and major upgrading (OR 0.58, 95% CI 0.48-0.69, p <0.01 and OR 0.67, 95% CI 0.49-0.96, p = 0.03, respectively). Men with prostate volume at the 25th percentile (36 cm(3)) were 50% more likely to experience upgrading than men with prostate volume at the 75th percentile (58 cm(3)). Conclusions: Of low risk cases 31% were upgraded at final pathology. Smaller prostate size predicts Gleason score upgrading in men with clinically low risk prostate cancer. This is important information when counseling patients on management and prognosis.