Comparing Surgical Routes for Robotic Prostate Cancer Surgery: Extraperitoneal vs. Transperitoneal Single-Port Approaches

Table of Contents

• Key Points
• Why This Research Matters
• How the Research Was Conducted
• Key Findings: What the Study Discovered
• Quality and Reliability of the Evidence
• What This Means for Patients
• Study Limitations
• Recommendations for Patients
• Frequently Asked Questions
• Source Information

Key Points

• Both extraperitoneal and transperitoneal single-port robotic prostatectomy are safe and effective for localized prostate cancer.
• Transperitoneal approach resulted in less blood loss, fewer serious complications, and better urinary continence recovery at 90 days.
• Extraperitoneal approach led to shorter hospital stays, with patients discharged about 8 hours earlier on average.
• No significant differences were found between approaches for operation time, pain scores, or positive surgical margins.
• The choice of approach should be individualized, considering surgeon experience, patient factors, and recovery priorities.

Why This Research Matters

Prostate cancer is one of the most common cancers in men, and surgery to remove the prostate gland — called radical prostatectomy — remains a cornerstone of treatment for localized disease. In recent years, robot-assisted radical prostatectomy (RARP) has become a leading surgical approach because it offers greater precision, smaller incisions, and faster recovery than traditional open surgery.

The newest advancement in this field is single-port (SP) robotic surgery, which was approved in the United States in 2018. Unlike traditional multiport robotic surgery that requires several incisions, single-port surgery uses just one small entry point. This approach offers a compact design, minimal trauma, and dual cameras, making it an increasingly popular alternative to conventional multiport RARP.

Surgeons can perform SP-RARP using two different routes to reach the prostate:

• The transperitoneal approach (SP-TPRP): The surgeon enters through the abdominal cavity (peritoneum), similar to traditional laparoscopic surgery.
• The extraperitoneal approach (SP-EPRP): The surgeon works in the space outside the abdominal cavity (the extraperitoneal space), without entering the peritoneum.

There has been ongoing debate among surgeons about which approach is better. Some argue that extraperitoneal surgery reduces operation time, blood loss, and hospital stays while lowering the risk of positive surgical margins (cancer cells remaining at the edge of the removed tissue) and complications. Others believe the transperitoneal route provides a better surgical view, enhanced precision, and greater protection of the urethra and surrounding nerves.

Previous analyses of traditional multiport robotic surgery suggested that the extraperitoneal approach offered faster operation times, shorter hospital stays, and fewer complications. However, until now, no study had systematically compared these two approaches specifically for single-port robotic surgery. This research was designed to fill that gap and help surgeons choose the best approach for their patients.

How the Research Was Conducted

The researchers followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, which are internationally recognized standards for conducting and reporting research reviews. The study was registered in advance with PROSPERO, an international database for systematic reviews, under registration number CRD42023409667.

A systematic search of four major medical databases — PubMed, Embase, Web of Science, and the Cochrane Library — was conducted to identify all relevant studies published up to February 2023. The search used combinations of keywords such as "transperitoneal radical prostatectomy," "extraperitoneal radical prostatectomy," "robotic surgical procedures," and "single port." The researchers also manually reviewed reference lists of relevant papers to ensure no important studies were missed.

Studies were selected based on strict criteria:

1. Patients: Men diagnosed with localized prostate cancer
2. Intervention: Extraperitoneal single-port robot-assisted radical prostatectomy
3. Comparison: Transperitoneal single-port robot-assisted radical prostatectomy
4. Outcomes: At least one measure of perioperative outcomes (surgery-related), functional outcomes (urinary continence), or oncological outcomes (positive surgical margins)
5. Study design: Case-control studies, cohort studies, or randomized controlled trials

Studies were excluded if they were conference reports, editorials, conference abstracts, non-comparative research, or lacked analyzable data.

Two reviewers independently extracted data from each study, including patient characteristics (age, body mass index, PSA levels, prostate size, tumor stage), perioperative outcomes (operation time, hospital stay, blood loss, pain scores), complications, continence recovery, and positive surgical margin rates. Any disagreements were resolved by a third reviewer.

For statistical analysis, the researchers used Stata 15.1 software. Results for yes/no outcomes were expressed as risk ratios (RR), while continuous outcomes (like blood loss or hospital days) were expressed as weighted mean differences (WMD), both with 95% confidence intervals. Statistical heterogeneity — variation between studies — was measured using the I² statistic. When I² was 50% or higher, indicating significant heterogeneity, a random-effects model was used; when below 50%, a fixed-effects model was applied. Sensitivity analyses were performed using the "leave-one-out" method, which removes one study at a time to verify that no single study was driving the results.

Study quality was assessed using the Newcastle–Ottawa Scale (NOS), a widely used tool that rates studies on participant selection, comparability of groups, and outcome assessment. Studies scoring below 5 points were excluded.

Key Findings: What the Study Discovered

After screening 318 studies from the four databases, the researchers identified 5 studies that met all inclusion criteria. These were prospective or retrospective cohort studies conducted in the United States, involving a total of 833 patients — 425 who underwent SP-TPRP and 408 who underwent SP-EPRP. Individual study sizes ranged from 34 to 476 patients.

Importantly, the two patient groups were well-matched at the start of the studies. There were no statistically significant differences between groups in age (p = 0.957), body mass index (p = 0.054), preoperative PSA levels (p = 0.139), history of previous abdominal surgery (p = 0.394), biopsy grade (p = 0.995), or prostate volume (p = 0.458). This means that differences in outcomes could be attributed to the surgical approach rather than to pre-existing differences between patients.

Operative Time: No Significant Difference

All 5 studies reported operative time for both approaches. The meta-analysis found no statistically significant difference in operation time between SP-EPRP and SP-TPRP (WMD: 3.02 minutes, 95% CI −32.49 to 38.52; p = 0.868).

This finding differs from earlier research on multiport robotic surgery. For example, a previous study by Uy and colleagues found that extraperitoneal surgery had a shorter operation time than transperitoneal surgery in multiport RARP, because it reaches the prostate directly without passing through the abdominal cavity. The researchers suggest several possible reasons for this difference in single-port surgery:

• Surgeon experience: Two of the included studies reported that surgeons were more experienced with SP-TPRP and less familiar with SP-EPRP, which could have lengthened SP-EPRP operation times.
• Patient body mass index (BMI): Higher BMI and thicker abdominal wall fat make surgery more difficult and time-consuming. This is especially true in transperitoneal surgery with the patient in the Trendelenburg position (head-down tilt).

The researchers note that if these factors were controlled, SP-EPRP might show a time advantage, as seen in multiport surgery.

Blood Loss: SP-TPRP Came Out Ahead

Five studies reported intraoperative blood loss, and the results significantly favored the transperitoneal approach. Patients in the SP-TPRP group lost, on average, 43.92 milliliters less blood during surgery than SP-EPRP patients (WMD: −43.92, 95% CI −69.81 to −18.04; p = 0.001). This difference was statistically significant, meaning there is strong evidence it is a real effect and not due to chance.

Hospital Stay: SP-EPRP Got Patients Home Sooner

Four studies reported on hospital stay duration, and here the extraperitoneal approach had the advantage. Patients in the SP-EPRP group were discharged on average 7.88 hours (roughly one-third of a day) earlier than SP-TPRP patients (WMD: 7.88, 95% CI 0.65 to 15.10; p = 0.03).

The researchers explain that the longer hospital stay with SP-TPRP may be related to peritoneal irritation and intestinal obstruction (blockage), which can occur when the abdominal cavity is entered during surgery. Because SP-EPRP bypasses the intestines, contact with the bowel is greatly reduced, potentially allowing for a quicker recovery and earlier discharge.

Postoperative Pain: Comparable Between Approaches

Four studies assessed pain scores at discharge. There was no significant difference between the two groups (WMD −0.08, 95% CI −0.40 to 0.23; p = 0.6). Patients reported similar levels of pain after both procedures, and opioid painkiller requirements were also comparable.

Complications: A Nuanced Picture

Postoperative complications were analyzed in two ways. When looking at the overall complication rate, there was no significant difference between the two approaches (RR 0.92, 95% CI 0.64 to 1.31; p = 0.74).

However, when the researchers focused on more serious complications — defined as Clavien-Dindo grade II or higher (complications requiring medication, surgical intervention, or intensive care) — a different picture emerged. The SP-TPRP group had a 45% lower risk of these serious complications compared to the SP-EPRP group (RR 0.55, 95% CI 0.31 to 0.99; p = 0.04). This means that while both approaches carry similar overall complication rates, the complications that do occur with SP-TPRP tend to be less severe.

The researchers noted that two of the included studies found a higher rate of lymphoid cysts (lymphoceles) — fluid collections that can form after pelvic lymph node dissection — in the SP-EPRP group. This may be because while SP-EPRP preserves the intraperitoneal structures, its working space is more limited and lacks the lymphatic channels needed to absorb fluid. Keeping the peritoneal space open during surgery or during lymph node removal may help reduce this complication.

Urinary Continence Recovery: SP-TPRP Had the Edge

Four studies reported on urinary continence recovery at 90 days after surgery, defined as using no pads or only one safety pad per day. The results significantly favored the transperitoneal approach, with patients in the SP-TPRP group being 23% more likely to achieve continence recovery at 90 days (RR 1.23, 95% CI 1.05 to 1.45; p = 0.04).

The researchers believe this advantage may stem from SP-TPRP's ability to better protect the urethral sphincter — the muscle that controls urine flow. The transperitoneal route allows better visualization and preservation of the external urethral sphincter and surrounding nerve tissue. The use of nerve-sparing techniques during surgery was also highlighted as an important factor in continence recovery, along with the surgeon's level of experience.

Positive Surgical Margins: No Difference

Four studies reported on positive surgical margins (PSM) — the presence of cancer cells at the edge of the removed prostate tissue, which is associated with a higher risk of cancer recurrence. There was no statistically significant difference between the two approaches (RR 1.03, 95% CI 0.80 to 1.32; p = 0.8). Both SP-EPRP and SP-TPRP achieved similar rates of complete cancer removal.

Quality and Reliability of the Evidence

The quality of the five included studies was assessed using the Newcastle–Ottawa Scale. All studies scored 5 or higher (out of a possible 9), with a median score of 7. Two studies earned a score of 8, two scored 6 or 7, and one scored 5. This indicates generally good methodological quality across the included research.

The researchers also examined statistical heterogeneity — how much the results varied between studies. For three outcomes, heterogeneity was high:

• Hospital stay: I² = 94.0% (very high variation between studies)
• Operation time: I² = 96.2% (very high variation)
• Blood loss: I² = 75.4% (substantial variation)

The researchers conducted meta-regression analyses based on publication year and sample size to explore the sources of this heterogeneity, but these factors did not explain the variation (p > 0.05). Due to the small number of studies, further subgroup analyses could not be performed.

Importantly, sensitivity analyses using the leave-one-out method showed that the results remained consistent when each study was removed in turn. This means no single study was responsible for driving any of the findings, which strengthens confidence in the conclusions.

Publication bias — the tendency for studies with positive results to be published more readily than those with negative results — was also assessed using funnel plots and Begg's regression tests. No evidence of publication bias was found for operative time, blood loss, or hospital stay (p > 0.05), supporting the integrity of the findings.

What This Means for Patients

For men facing prostate cancer surgery, this study offers several important takeaways. Both surgical approaches for single-port robotic prostatectomy are safe and effective, giving surgeons and patients flexibility in choosing the best option based on individual circumstances.

Here is what the evidence suggests in practical terms:

• If faster recovery of urinary control is a priority: The transperitoneal approach (SP-TPRP) appears to offer a better chance of regaining continence by 90 days after surgery. This is a critical quality-of-life consideration for many men after prostatectomy.
• If minimizing serious complications is the goal: SP-TPRP was associated with fewer Clavien-Dindo grade II and above complications. Patients may be less likely to experience complications requiring medical intervention or readmission.
• If reducing blood loss matters: SP-TPRP showed significantly lower intraoperative blood loss, which can contribute to a smoother recovery and reduced need for transfusions.
• If getting home sooner is important: The extraperitoneal approach (SP-EPRP) was associated with shorter hospital stays, which may be appealing for patients who prefer minimal time in the hospital.
• If you're concerned about cancer control: Both approaches achieved similar rates of negative surgical margins, meaning cancer control outcomes were comparable.

The choice between these two approaches should be discussed carefully with your surgical team. Factors that may influence the decision include the surgeon's level of experience with each technique, your body mass index, your previous surgical history, and the specific characteristics of your cancer.

Study Limitations

While this meta-analysis provides valuable insights, it has several limitations that should be acknowledged:

• Small number of studies: Only 5 studies met the inclusion criteria, which limits the statistical power of the analysis.
• No randomized controlled trials: All included studies were prospective or retrospective cohort studies, which are more susceptible to bias than randomized trials. Patients were not randomly assigned to one approach or the other, so unmeasured factors could have influenced outcomes.
• Geographic limitation: All studies were conducted in the United States, and results may not generalize to other countries with different healthcare systems, surgical training, or patient populations.
• High heterogeneity: Results for hospital stay, operation time, and blood loss showed considerable variation between studies, which may reflect differences in surgical technique, patient characteristics, or institutional practices.
• Surgeon experience was not uniform: Some surgeons were more experienced with one approach than the other, which could have affected outcomes such as operation time and complication rates.
• Limited follow-up duration: Continence was assessed at 90 days, but longer-term outcomes beyond this period were not available in the included studies.
• Subgroup analysis not possible: The small number of studies prevented the researchers from conducting meaningful subgroup analyses to explore how factors like BMI, cancer stage, or nerve-sparing technique might influence outcomes.

Recommendations for Patients

If you or a loved one is considering robot-assisted radical prostatectomy, here are some practical recommendations based on this research:

1. Have an open discussion with your surgeon about which approach — extraperitoneal or transperitoneal — is recommended for your specific situation, and why. Ask about their personal experience with each technique.
2. Consider your priorities. If urinary continence recovery is your primary concern, the transperitoneal approach may offer advantages. If you prefer a shorter hospital stay, the extraperitoneal approach may be worth discussing.
3. Ask about nerve-sparing techniques. The study found that nerve preservation during surgery significantly affects continence recovery. Ask your surgeon whether you are a candidate for nerve-sparing surgery, as this can depend on the stage and location of your cancer.
4. Discuss your risk factors. Your BMI, previous abdominal surgeries, and prostate size can all affect surgical outcomes. Be transparent with your surgical team about your medical history.
5. Understand that both approaches are safe and effective. The most important factor in a good outcome is often the skill and experience of your surgical team, rather than the specific approach used.
6. Set realistic expectations. While this study shows SP-TPRP offers a 23% better chance of continence recovery at 90 days, individual results vary widely. Many men continue to see improvements in continence for up to 12 months after surgery.

The researchers concluded that this study successfully demonstrates that both extraperitoneal and transperitoneal SP-RARP approaches are safe and effective for treating localized prostate cancer. They note that SP-TPRP appears to offer advantages in blood loss, serious complication rates, and continence recovery, although it is accompanied by longer hospital stays. This information provides valuable insights for clinicians selecting the most suitable surgical method for each patient, and for patients themselves, who deserve to be active participants in this important decision.

Frequently Asked Questions

What are the two surgical routes for single-port robotic prostatectomy?

They are the transperitoneal approach, which enters through the abdominal cavity, and the extraperitoneal approach, which works outside the abdominal cavity. Both are minimally invasive techniques to remove the prostate for localized prostate cancer. Each route has specific advantages and disadvantages, and both are considered safe and effective options.

Which approach leads to a shorter hospital stay?

The extraperitoneal approach (SP-EPRP) led to shorter hospital stays. Patients were discharged about 7.88 hours earlier on average than those who had the transperitoneal approach. This may be because the extraperitoneal route avoids the abdominal cavity, potentially allowing faster bowel recovery.

Is urinary continence recovery better with one approach?

Yes. The transperitoneal approach (SP-TPRP) offered better urinary continence recovery at 90 days after surgery. Patients were 23% more likely to achieve continence, defined as using no pads or only one safety pad per day. Better visualization of the urethral sphincter may explain this advantage.

Do the two approaches differ in cancer control?

No significant difference was found in positive surgical margins, which is the presence of cancer cells at the edge of the removed prostate. Both the extraperitoneal and transperitoneal approaches achieved similar rates of complete cancer removal. So the choice between approaches does not appear to affect this important oncological outcome.

Which approach has fewer serious complications?

The transperitoneal approach was associated with a 45% lower risk of serious complications, defined as Clavien-Dindo grade II or higher, which require medication, surgery, or intensive care. Overall complication rates were similar, but complications with the transperitoneal approach tended to be less severe.

How should I decide which surgical approach is right for me?

Discuss with your surgeon which approach fits your situation. Consider your priorities: transperitoneal may offer better continence recovery, less blood loss, and fewer serious complications, but longer hospital stay. Extraperitoneal may allow earlier discharge. Factors like surgeon experience, your BMI, previous abdominal surgeries, and cancer characteristics also matter.

When should a patient with localized prostate cancer seek a second opinion about the choice between transperitoneal and extraperitoneal single-port robotic prostatectomy?

In localized prostate cancer, both single-port robotic surgical routes are safe and effective, but they differ in trade-offs: the transperitoneal route has less blood loss, fewer serious complications, and better 90-day urinary continence recovery, while the extraperitoneal route allows a shorter hospital stay. A second opinion can help you weigh these differences against your priorities, confirm that the recommended approach fits your cancer characteristics, and ensure you have explored nerve-sparing options. Diagnostic Detectives Network provides independent expert second opinions.

Source Information

Original Article: "Perioperative, function, and positive surgical margin in extraperitoneal versus transperitoneal single port robot-assisted radical prostatectomy: a systematic review and meta-analysis"

Authors: Jiang Y, Liu Y, Qin S, Zhong S, Huang X.

Journal: World Journal of Surgical Oncology (2023) 21:383

DOI: https://doi.org/10.1186/s12957-023-03272-7

Registration: PROSPERO (CRD 42023409667)

This patient-friendly article is based on peer-reviewed research. It is intended for educational purposes and should not replace individualized medical advice from your healthcare provider. Always discuss your specific treatment options with your urologist or surgeon.