Impact of Prostate Size on the Functional and Oncological Outcomes of Robot-assisted Radical Prostatectomy.

ABSTRACT

BACKGROUND AND OBJECTIVE: Robot-assisted radical prostatectomy (RARP) is the main surgical approach for treatment of prostate cancer in the USA. Prostate size is always depicted as a factor affecting the outcomes of RARP as shown by many studies, but these studies are limited to a small number of patients. Our aim was to evaluate functional and oncologic outcomes of RARP across varying prostate size measured as prostate specimen weight. METHODS: A cohort of 14 481 patients who underwent RARP in a single center was divided into four groups according to prostate specimen weight group 1, <50 g; group 2, 50-100 g; group 3, 100-150 g; and group 4, >150 g. Perioperative and postoperative variables and pathological and functional outcomes were compared among the four groups. Cumulative incidence functions were plotted to visualize the distribution of event-time variables among the groups, and differences were evaluated using the log-rank test. KEY FINDINGS AND LIMITATIONS: Patients with larger prostates (groups 3 and 4) were more likely to have higher prostate-specific antigen (PSA), lower biopsy grade group, and worse baseline urinary and sexual characteristics. Group 4 had lower rates of full nerve-sparing surgery (13.7% vs 38.3%) and lymph node dissection (51.3% vs 71.4%), more pT2 disease (69.8% vs 60.3%), less pT3 disease (30.2% vs 39.7%), and lower rates of positive surgical margins (12.8% vs 19.3%) and biochemical recurrence (5.9% vs 7.5%) than group 1. Finally, we observed differences in functional outcomes among the groups for greater prostate size, and patients in group 4 had worse rates of urinary continence (77.8% vs 89.5%) and recovery of sexual function (70.0% vs 84.1%) than group 1. Our study is limited by its retrospective design. CONCLUSIONS AND CLINICAL IMPLICATIONS The results demonstrate that in this large cohort of patients, greater prostate size affects multiple outcomes, including the rate of nerve-sparing surgery, potency and continence recovery, and oncological and pathological outcomes. These data will be valuable when counseling patients regarding possible RARP outcomes and the timeline for recovery. PATIENT SUMMARY: Our study shows that prostate size can affect the outcomes of robot-assisted removal of the prostate for patients with prostate cancer. Larger prostate size can be associated with worse functional outcomes after surgery.