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

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.