Robot-assisted prostatectomy in obese patients: how influential is obesity on operative outcomes?

Objective: To compare operative outcomes of robot-assisted prostatectomy (RARP) in obese and non-obese patients with prostate cancer. Materials and Methods: A literature search of MEDLINE, EMBASE, Google Scholar and the Cochrane Library was performed up to March 2014. All studies assessing operative outcomes of RARP in obese and non-obese patients were included. Outcome measures were perioperative and functional results, including operating time, estimated blood loss (EBL), complications, length of hospital stay (LOS), positive surgical margins (PSM) and recovery of continence and potency. Pooled odds ratios (OR) and weighted mean differences (WMD) with 95% confidence intervals (CI) were calculated using fixed-effects or random-effects model. Subgroup analysis was performed for institutions with greater experience of RARP in obese cases. Results: Thirteen observational studies from 12 study population were included for 1821 obese patients compared with 4801 non-obese patients. Operating time (P = 0.0001; WMD: 24.28; 95%CI, 11.93-36.64) and EBL (P = 0.003; WMD: 38.28; 95%CI, 13.45-63.11) were significantly increased in obese patients compared with non-obese counterparts. There was no significant difference in complications, LOS or PSM rates. Subgroup analysis for studies involving ≥100 obese cases showed consistent results, but the increases in operating time (9.8 min; 95%CI, 1.7-18 min) and EBL (14 ml; 95%CI, 5.0-23 ml) were much lower compared with the original analysis. As for functional outcomes, obese patients showed significantly higher probabilities of incontinence (P = 0.003; OR: 1.41; 95%CI, 1.13-1.77) and impotency (P = 0.02; OR: 1.29; 95%CI, 1.03-1.61) at 1 year. Conclusions: Perioperative outcomes of RARP in obese patients are comparable with those in non-obese patients, except for significant but small increases in operating time and EBL. Surgeons should initiate RARP procedures in obese cases after overcoming the learning curve. Further studies should be performed to evaluate the functional outcomes for obese patients undergoing RARP.