Should we perform Retzius-sparing RALP or standard RALP for clinically localized prostate cancer?

Review question

In men with prostate cancer who are having their prostate removed using surgery assisted by a robotic device (called robotic-assisted laparoscopic prostatectomy or RALP), how does an approach that leaves the tissue connections between the front of the bladder to the back of the abdominal wall intact (so-called Retzius-sparing RALP) compare to surgery where these connections are cut (standard RALP). 

Background

Urologists often use a robot to remove the prostate in men with prostate cancer. After surgery, men have a catheter that drains urine from their bladder. When this is removed, most men leak urine for some time. This problem is called incontinence and usually gets better within six to 12 months in most men. However, it can be very bothersome during this time. 

Study characteristics

We included five studies in which chance determined whether men had Retzius-sparing RALP or standard RALP. These studies included 571 men with an average age of about 65 years. The average prostate-specific antigen level (PSA; higher levels of which may indicate that the man has prostate cancer) was 6.9 ng/mL and a little over half (54.2%) had prostate cancer that was found based on the PSA level but could not felt on rectal exam. In 233/331 (70.4%) men, they tried to spare the nerves that are responsible for erections. 

Key results

We found that the Retzius-sparing RALP probably improves continence within one week after the catheter comes out. It may also improve continence three months after surgery. We are very uncertain how serious unwanted effects compare between the two ways of doing the surgery. 

Continence after Retzius-sparing RALP may also be better after six months. At 12 months, continence is probably similar. 

Men who have Retzius-sparing RALP may be more likely to have positive surgical margins, meaning they still have cancer cells right at the cut edge of the prostate when viewed under the microscope. This may make it more likely that the cancer will come back. We are very uncertain about the effect of Retzius-sparing RALP on PSA level that goes up within 12 months of surgery, which signals that there is cancer left behind. Urinary quality of life at three months may be similar with both types of surgery. We are very uncertain how Retzius-sparing RALP affects the ability to achieve an erection. 

Quality of the evidence

The quality of evidence ranged from moderate to very low depending on the outcome, meaning that we have moderate to very low confidence in the results.

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. 

Read the full abstract...
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 strategy: 

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).

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