Retzius-sparing versus standard robotic-assisted laparoscopic prostatectomy for the treatment of clinically localized prostate cancer

BACKGROUND: Robotic-assisted laparoscopic prostatectomy (RALP) is widely used to surgically treat clinically localized prostate cancer. It is typically performed using an approach (standard RALP) that mimics open retropubic prostatectomy by dissecting the so-called space of Retzius anterior to the bladder. An alternative, Retzius-sparing (or posterior approach) RALP (RS-RALP) has been described, which is reported to have better continence outcomes but may be associated with a higher risk of incomplete resection and positive surgical margins (PSM). OBJECTIVES: To assess the effects of RS-RALP compared to standard RALP for the treatment of clinically localized prostate cancer. SEARCH METHODS: We performed a comprehensive search of the Cochrane Library, MEDLINE, Embase, three other databases, trials registries, other sources of the grey literature, and conference proceedings, up to June 2020. We applied no restrictions on publication language or status. SELECTION CRITERIA: We included trials where participants were randomized to RS-RALP or standard RALP for clinically localized prostate cancer. DATA COLLECTION AND ANALYSIS: Two review authors independently classified and abstracted data from the included studies. Primary outcomes were: urinary continence recovery within one week after catheter removal, at three months after surgery, and serious adverse events. Secondary outcomes were: urinary continence recovery six and 12 months after surgery, potency recovery 12 months after surgery, positive surgical margins (PSM), biochemical recurrence-free survival (BCRFS), and urinary and sexual function quality of life. We performed statistical analyses using a random-effects model. We rated the certainty of evidence using the GRADE approach. MAIN RESULTS: Our search identified six records of five unique randomized controlled trials, of which two were published studies, one was in press, and two were abstract proceedings. There were 571 randomized participants, of whom 502 completed the trials. Mean age of participants was 64.6 years and mean prostate-specific antigen was 6.9 ng/mL. About 54.2% of participants had cT1c disease, 38.6% had cT2a-b disease, and 7.1 % had cT2c disease. Primary outcomes RS-RALP probably improves continence within one week after catheter removal (risk ratio (RR) 1.74, 95% confidence interval (CI) 1.41 to 2.14; I2 = 0%; studies = 4; participants = 410; moderate-certainty evidence). Assuming 335 per 1000 men undergoing standard RALP are continent at this time point, this corresponds to 248 more men per 1000 (137 more to 382 more) reporting continence recovery. RS-RALP may increase continence at three months after surgery compared to standard RALP (RR 1.33, 95% CI 1.06 to 1.68; I2 = 86%; studies = 5; participants = 526; low-certainty evidence). Assuming 750 per 1000 men undergoing standard RALP are continent at this time point, this corresponds to 224 more men per 1000 (41 more to 462 more) reporting continence recovery. We are very uncertain about the effects of RS-RALP on serious adverse events compared to standard RALP (RR 1.40, 95% CI 0.47 to 4.17; studies = 2; participants = 230; very low-certainty evidence). Secondary outcomes There is probably little to no difference in continence recovery at 12 months after surgery (RR 1.01, 95% CI 0.97 to 1.04; I2 = 0%; studies = 2; participants = 222; moderate-certainty evidence). Assuming 982 per 1000 men undergoing standard RALP are continent at this time point, this corresponds to 10 more men per 1000 (29 fewer to 39 more) reporting continence recovery.  We are very uncertain about the effect of RS-RALP on potency recovery 12 months after surgery (RR 0.98, 95% CI 0.54 to 1.80; studies = 1; participants = 55; very low-certainty evidence).  RS-RALP may increase PSMs (RR 1.95, 95% CI 1.19 to 3.20; I2 = 0%; studies = 3; participants = 308; low-certainty evidence) indicating a higher risk for prostate cancer recurrence. Assuming 129 per 1000 men undergoing standard RALP have positive margins, this corresponds to 123 more men per 1000 (25 more to 284 more) with PSMs. We are very uncertain about the effect of RS-RALP on BCRFS compared to standard RALP (hazard ratio (HR) 0.45, 95% CI 0.13 to 1.60; I2 = 32%; studies = 2; participants = 218; very low-certainty evidence). AUTHORS' CONCLUSIONS: Findings of this review indicate that RS-RALP may result in better continence outcomes than standard RALP up to six months after surgery. Continence outcomes at 12 months may be similar. Downsides of RS-RALP may be higher positive margin rates. We are very uncertain about the effect on BCRFS and potency outcomes. Longer-term oncologic and functional outcomes are lacking, and no preplanned subgroup analyses could be performed to explore the observed heterogeneity. Surgeons should discuss these trade-offs and the limitations of the evidence with their patients when considering this approach.