Does larger prostate size provide protection for cancer specific outcomes in localized prostate cancer.

Abstract

Benign prostatic hyperplasia is common in the aging population and frequently comorbid with localized prostate cancer. Large prostate volume places significant challenges in robotic prostatectomy including reduced mobility and visualization. The goal of this study is to evaluate the effect of prostate volume as a continuous variable on cancer specific outcomes. Three thousand four hundred and twenty five patients with localized prostate cancer at a single institution who underwent robotic prostatectomy were retrospectively reviewed. A number of preoperative, operative, and postoperative variables were collected to evaluate cancer specific outcomes including pathologic stage, tissue margins, and biochemical recurrence (BCR). Logistic regression models and univariate and multivariate analyses were implemented for pathologic stage T3 and BCR respectively. The median follow up time was 52 months (IQR 18-95). 37.4% of the patients had a final pathologic stage of T3 or higher, 21.2% experienced positive surgical margins, and 24.7% of patients experienced BCR. Prostate size was a significant predictor of all three outcomes of interest. Increasing prostate size was protective against both higher pathologic stage and positive surgical margins (odds ratio = 0.989, 0.990 respectively, p < 0.001). There was a modest increase in the risk of BCR with increasing gland size (hazard ratio = 1.006, p < 0.001). These results were most significant for patients with Gleason Grade Groups 1 and 2 prostate cancer. Prostate size is a commonly determined clinical factor that effects both surgical planning and cancer specific outcomes. Increasing prostate size may offer protection against higher stage disease and positive surgical margins. While surgically challenging, favorable oncologic outcomes can be consistently achieved for patients with low-intermediate risk disease.