Nerve-sparing RP May Not Raise Positive Margin Risk

Patients who had nerve-sparing radical prostatectomy had lower risks of urinary incontinence.
Patients who had nerve-sparing radical prostatectomy had lower risks of urinary incontinence.

Using a nerve-sparing technique that preserves the neurovascular bundles during radical prostatectomy (NSRP) does not appear to increase the chances of positive surgical margins (PSMs), according to a new meta-analysis.

Rodney H. Breau, MSc, MD, and colleagues from The Ottawa Hospital in Ontario, Canada conducted a systematic review and meta-analysis of 124 mostly observational studies of 73,448 patients (average age 56.1 to 70 years) published after 2000, when surgical techniques had changed. NSRP did not increase the risks of positive surgical margins (PSMs) or biochemical recurrence in patients with pT2 or pT3 disease compared with non-nerve-sparing radical prostatectomy.

“The absence of an association between nerve-sparing technique and a positive surgical margin seems surprising, since closer dissection to the prostate gland should intuitively result in increased risk of incision into tumor …  Appropriate patient selection (selection bias) may certainly explain these findings,” Dr Breau and colleagues wrote in The Journal of Urology. “While we stratified patients based on tumor stage, we were unable to adjust for some factors independently associated with positive surgical margins such as tumor volume, PSA, side-specific outcomes, or surgeon experience.”

It is also possible that non-nerve-sparing procedures did not always involve a wide extrafascial resection, they noted. Some other studies detailing the surgical technique used found increased risks of positive surgical margin and biochemical recurrence with NSRP.

Patients who had NSRP had 25% and 39% lower risks of urinary incontinence at 3 and 12 months after surgery, respectively. The investigators determined that 1 additional patient would remain continent for every 12 men treated with NSRP. “Lack of thermal injury and greater preservation of tissue around the urethra and pelvic floor during nerve spare may explain the association,” Dr Breau and colleagues explained.

The study also found 23% and 47% lower risks of erectile dysfunction with NSRP at 3 months and 12 months after surgery, in agreement with previous research. Similar results were obtained for unilateral and bilateral nerve-sparing procedures. For 1 additional patient to maintain erectile function, 3 would need to receive NSRP.

As the included studies were mostly observational, future randomized controlled trials are still needed to fully understand the risks and benefits of NSRP.

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