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Robotic surgery in urology: facts and reality. What are the real advantages of robotic approaches for prostate cancer patients?

Ploussard, Guillaume

doi: 10.1097/MOU.0000000000000470
ROBOTIC SURGERY IN UROLOGY: FACTS AND REALITY: Edited by Alexandre de la Taille and Jim C. Hu
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Purpose of review Despite the worldwile increasing use of robotic assistance for oncology surgery, no level 1 evidence-based benefit favoring robot-assisted radical prostatectomy (RARP) versus pure laparoscopic or open approaches has been demonstrated. We aimed to perform an update of the available evidence by evaluating most recent 2016–2017 data.

Recent findings Population-based and prospective nonrandomized studies and one phase III randomised trial have been recently published. Early results from the phase III trial suggested that RARP led to similar early functional and oncologic outcomes compared with open radical prostatectomy. Shorter operative time, hospital stay, and lower complications rate and blood loss were reported in RARP group compared with open radical prostatectomy group. Population-based data did not demonstrate any benefit from one approach over another in terms of functional and oncologic outcomes. Robot assistance is predictive for improved potency recovery in organ-confined tumor in one large prospective trial. Main limitations, different among studies, were lack of randomization or single operator cohorts, short-term follow-up, and absence of confounding factors analysis.

Summary Robotic assistance seems to confer better results than open radical prostatectomy procedures in terms of intra- and immediate postoperative parameters (operative time, blood loss and hospital stay). Clear advantages of one technique over another on robust functional or oncologic endpoints remain unproven.

Division of Urology Saint Jean Languedoc Hospital, and Institut Universitaire du Cancer Oncopole, Toulouse, France

Correspondence to Dr Guillaume Ploussard, Division of Urology Saint Jean Languedoc Hospital, and Institut Universitaire du Cancer Oncopole, 20, route de Revel, 31500, Toulouse, France. Tel: +33 5 61 54 90 45; fax: +33 5 62 47 19 11; e-mail: g.ploussard@gmail.com

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INTRODUCTION

The ideal surgical approach to perform a radical prostatectomy remains thoroughly debatable. Recent published clinical trials have exacerbated the debate. Until now, no high level of evidence study has demonstrated a clear superiority of one approach over another in terms of oncologic or functional outcomes. Nevertheless, some academic studies have suggested the superiority of robot-assisted radical prostatectomy (RARP) over pure laparoscopic or open radical prostatectomy in operative and functional outcomes [1–3]. Several reviews and meta-analyses of the literature recently highlighted the potential benefit from RARP regarding the functional outcomes without hindering oncologic control [4–11]. Few controlled trials with small sample size cohorts have compared pure laparoscopic radical prostatectomy and RARP, suggesting better early functional outcomes by using robotic assistance [12–13]. However, the level of evidence remains weak given the lack of randomized controlled trials and the number of factors (surgeon experience, disease staging, nerve-sparing techniques) that need to be taken into account.

The vast majority of studies included or not in meta-analyses came from academic and high-volume centers and mainly involved experienced surgeons. These results could not reflect the outcomes in the general population of localised prostate cancer patients, and should be interpreted with caution. Thus, the debate remains still open.

Recently, population-based, prospective studies and one phase III controlled trial comparing open radical prostatectomy and RARP have been published, justifying this updated literature comprehensive review [14▪,15▪,16,17▪▪,18].

Box 1

Box 1

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ROBOTIC RADICAL PROSTATECTOMY: HISTORY AND CURRENT ASPECTS

Radical prostatectomy is a standard treatment for localized prostate cancer, and all standard surgical approaches (open surgery, pure or robot-assisted procedure) are a validated and recommended options. To date, identifying the optimal surgical approach for patients with localized prostate cancer remains still controversial because of the lack of robust data.

The first minimally invasive laparoscopic radical prostatectomy was performed in 1991 and was thought not to be feasible because of excessive operative time [19,20]. However, in the following years, the development of minimally invasive surgery continued and some centers have been able to report considerable experience and to standardize the technique. Pure laparoscopic radical prostatectomy, and then RARP procedures have showed significantly lower blood loss and transfusions, and a shorter length of hospital stay than the open radical prostatectomy. These benefits seems to occur without sacrificing the oncologic standards established by the open approach.

Nevertheless, pure laparoscopic radical prostatectomy remains a technically demanding procedure. The two-dimensional vision with acquisition of different anatomical perspectives, the loss of some freedom of motion, and hand-eye coordination contribute to the steep learning curve of laparoscopy. These difficulties and the emergence of robotic assistance that facilitates laparoscopy lead laparoscopic urologists to develop the technique of RARP [22]. One of the purposes of the robotic assistance was to reduce the learning curve, even in laparoscopically naïve surgeons without sacrificing the oncological standards established by the open approach [21]. Robotic assistance offers technical parameters which may reduce the learning curve: a magnified three-dimensional visual field, a greater range of instrument motion (6 degrees of freedom), a minimization of tremor, and an ergonomic console to improve surgeon's comfort. Thus, the two first controlled trials involved experienced laparoscopic surgeons and compared RARP with pure laparoscopic radical prostatectomy, and large single-center retrospective studies [12,13,22].

Until recently, most of systematic reviews and meta-analysis tended to conclude that there were not sufficient data to prove the superiority of any surgical approach in terms of long-term functional and oncologic outcomes. Main and recent systematic reviews and meta-analysis are illustrated in Table 1. The most positive ones suggested the potential benefit from RARP regarding early functional and intraoperative outcomes [4–11].

Table 1

Table 1

However, because of a lack of large randomized controled trials, differences in patient characteristics or surgical experience might explain differences in outcomes between surgical approaches.

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WHAT DID WE LEARN RECENTLY FROM PROSPECTIVE STUDIES

Early results from an Australian phase III trial has been published at the end of 2016 and is currently the first controlled study comparing open radical prostatectomy and RARP [17▪▪]. In this study, patients with localized prostate cancer were randomized to undergo open radical prostatectomy (n = 151) or RARP (n = 157). All the RARP cases were performed by one surgeon having a 200-case experience as compared with 1500-case experience for the open radical prostatectomy surgeon who performed also all open cases. Primary outcomes were urinary function and sexual function assessed by the EPIC questionnaires and recorded at week 6 and 12, and month 24.

For this primary endpoint, no difference was reported between both arms after a short follow-up (12 weeks). Longer follow-up was not reported.

Regarding secondary endpoints, RARP provided better intra- and postoperative outcomes. Operative time was shorter for RARP with a decreased rate of complications (8 vs. 2%, P = 0.02). Mean blood loss was reduced by approximately 900 ml in the RARP group. However, no difference in terms of transfusion rate was observed that could be explained by the routine use of cell saver in the open radical prostatectomy group.

Hospital stay was significantly shorter in the RAP group, and reduced by 1.7 day compared with the stay after open radical prostatectomy (P < 0.001). This may be partially explained by a strong but not significant trend favoring RARP for a lower postoperative complications rate (9 vs. 4%, P = 0.051).

Analyses have also demonstrated significantly lower pain scores at day 1 and week 1 after surgery in the RARP versus open radical prostatectomy group, and higher physical quality of life at week 6. Time to return to work (assessed in 42% of the overall cohort) was 43 days in both cohorts without significant difference.

Limitations of this study can be highlighted. Only two experienced surgeons (one represented in each arm) performed all procedures. The simple conclusion could be that one surgeon doing RARP obtains good and similar functional outcomes compared with those obtained by another experienced open radical prostatectomy surgeon. The generalization of such a conclusion to the whole urologist community remains debatable. Even if the allocation to treatment was randomized, patients and caregivers were not blinded to the procedure, and this lack introduced comparison and interpretation biases. Longer follow-up is awaited as a 3-month follow-up cannot be considered as sufficient to draw any conclusion. Indeed, both erectile and continence recovery can take up to 2 years after surgery.

Recently, an update of the LAParoscopic Prostatectomy Robot Open (LAPPRO) study has been published, evaluating the sexual and oncologic outcomes between open radical prostatectomy and RARP [14▪]. A prior LAPPRO study had reported significantly better erectile function outcomes at 12 months for the robotic approach, but the absolute difference was only 4.3% [23].

The LAPPRO study is a large, prospective nonrandomized trial consisting in a prospective data collection of Swedish patients undergoing a radical prostatectomy. No randomization was done but the characteristics of the public health system in Sweden induces that virtually all patients within a specific geographical area are operated on at one hospital. The surgical approach depends on the procedure used in this regional hospital. The authors by this way argue randomization was replaced by place of residence and this provided a high validity of this prospective trial.

Overall, 2545 patients who underwent radical prostatectomy were included and followed prospectively from September 2008 to November 2011, by 50 different surgeons from 14 centers. Out of these 14 centers, seven used robotic assistance and seven open radical prostatectomy. The cohort consisted of 1792 patients who had undergone a RARP and 753 open radical prostatectomy. This represented for around half the annual case-load in Sweden during the same period. Two thirds of men were preoperatively potent. Baseline characteristics were quite comparable between both groups.

A nerve-sparing technique was more likely performed in RARP cases than open radical prostatectomy (84.0 vs. 68.2%), regardless of the preoperative risk group. Moreover, the surgeon-reported degree of nerve preservation was related to erectile function recovery. In the postoperative course, patients in the open radical prostatectomy group used more frequently invasive erectile drugs than patients with RARP at all time points.

Postoperative erectile function recovery was better after RARP in low-risk and intermediate-risk patients, at all time points. Conversely, the recovery was higher in the open radical prostatectomy group when analysing only high-risk patients with prostate cancer 2 years after the surgery.

The second endpoint was the surgical margin status. In pT2 tumors, the positive surgical margin rate was 7% higher in the RARP compared with the open radical prostatectomy group (17 vs. 10.2%). In pT3 disease, this rate was 15% higher in open radical prostatectomy cohort (48.1 vs. 33.3%). No difference in terms of biochemical recurrence was noted between both arms. Potential factors explaining this significant difference could be the traumatic manipulation of gland during the neuro-vascular dissection in RARP. Urologists performing RARP may also expand indications of nerve preservation due to the vision magnification, exposing patient selected on not stringent criteria to an increased risk of positive margins. Interestingly, in high-risk cases, this link was inverted with a higher risk of margins in open radical prostatectomy cases suggesting that the tactile feedback was not an oncologic advantage in cases of not organ-confined disease. The main limitations of this study were the lack of randomization, the absence of integration of confounding factors (hospital volume, surgeon experience) that could introduce interpretation biases.

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WHAT DID WE LEARN RECENTLY FROM POPULATION-BASED STUDIES

The vast majority of available evidence when comparing surgical approaches for radical prostatectomy includes experience from academic or highly experienced surgeons and centers. The generalization of such results may be questionable. Some argue that population-based studies could better reflect the real-life practice, approaching the populations of nonacademic centers where most patients are treated.

Herlemann et al. [15▪] have assessed in a community-based study the surgical outcomes and patient-reported urinary and sexual quality of life over time in patients undergoing open radical prostatectomy versus RARP. The authors used the Cancer of the Prostate Strategic Urologic Research Endeavor (CaPSURE) that is a large, nationwide, prospective, mainly community-based American disease registry. Patients undergoing radical prostatectomy for localized prostate cancer between 2004 and 2016 were included in the analysis. Self-reported, validated questionnaires were used to evaluate urinary and sexual quality of life during follow-up. Questionnaires used were the Prostate Cancer Index (PCI) until 2011 and then the Expanded Prostate Cancer Index Composite Short Form (EPIC-26).

Out of 15 209 CaPSURE patients, 1821 have been included undergoing open (n = 1137) or robot-assisted (n = 755) radical prostatectomy. Both arms were not statistically similar regarding baseline characteristics given that patients undergoing open surgery were more likely to have low-risk prostate cancer compared with patients included in the robot-assisted group (64 vs. 46%, P < 0.01). Thus, pathologic Gleason score and pT stage were significantly higher in the robot-assisted group limiting comparisons of oncologic outcomes between both groups. Nevertheless, in spite of these discrepancies, the 5-year actuarial biochemical-free survival was comparable in both groups (87 and 85%, P = 0.38).

Mean scores did not significantly differ between the two groups at baseline and at follow-up time points. However, the open surgery group reported significantly superior scores in urinary incontinence and urinary bother scores within the first year after surgery compared with the robot-assisted group. No difference in continuous sexual bother scores was reported. Both groups’ patients demonstrated a continuous improvement in quality of life during postoperative follow-up. Functional recovery tended to stabilize at 2–3 years after surgery.

To summarize, the patterns of change over time were largely similar between both surgical groups.

The main limitation of such population-based study is that the repartition of baseline characteristics of comparative cohorts may strongly differ from prospective series and lead to comparison biases. Recently, Schiffmann et al. demonstrated using the SEER database that characteristics such as education, region of residence, and population density clearly affect the decision of undergoing an RARP or an open radical prostatectomy [16]. The clinical stage of the disease, and the surgeon volume also influence the surgical approach choice, leading to strong statistical issues when comparing the surgical technique used.

Another study from the SEER database has confirmed the increasing use the RARP over time [18]. The rate of radical prostatectomy performed by robotics increased from 13.6% in 2003–2004 to 72.6% in 2011–2012 in a cohort of more than 15 000 radical prostatectomy cases. Regarding the cancer-specific and all-cause mortality, comparable risks were reported whatever the surgical approach with a less frequent use of adjuvant treatments in case of RARP.

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CURRENT LIMITATIONS, PERSPECTIVES, AND CONCLUSION

The number of RARP is increasing worldwide at the expense of both pure laparoscopic and open radical prostatectomy procedures. In the United States, up to 80% of radical prostatectomy are now performed robotically. Nevertheless, the benefit from one technique over another for RP remains debatable. The reasons for this lack of robust data are multiple.

First, randomization in surgical trials is very difficult to achieve. When the allocation to treatment is obtained, patients and surgeons are not blinded to the procedure given the obvious differences in skin incision between laparoscopic and open surgeries leading to interpretation biases. Subjective differences between techniques are often described. The magnification of vision provided by the robot could lead robotic surgeons to choose a dissection plane closer to the prostate that could result in surgical margin to the prostate capsule in low-risk tumors. Thus, the use of robotics may result in obtaining the intrafascial plane more frequently and easily compared with open radical prostatectomy. Potential earlier recovery of erectile function with RARP in lower-risk patients is counterbalanced by a higher risk positive margin rates in not strictly selected low-risk cases. However, it is worthy to note that the evaluation of the plane of neurovascular bundle dissection is mainly subjective and not based on the pathologic outcome. Conversely, the potential advantage from the tactile feedback during open radical prostatectomy fails to show any oncologic benefit even in high-risk cases.

In case of absence of long-term follow-up, positive surgical margin status may be an interesting surrogate of future oncologic results and an early outcome measure in comparing surgical modalities. Globally, literature review shows equivalent margin status and mid-term biochemical recurrence rates whatever the surgical approach. Surgeon volume and center experience are important confounding factors to analyze when comparing oncologic outcomes. Several series constantly reported that lower surgeon volume were associated with increased risk of recurrence after a more than 5-year follow-up [24,25]. Experience of the center and of the surgeon, learning curve strongly influence both functional and oncologic outcomes and could compromise data interpretation. It is interesting to notice that each operative, pathological, or functional data requires a different learning curve which should be assessed separately for each of these parameters when comparing surgical approaches. The operative time should not be the single variable evaluated to define the learning curve and the surgeon's expertise.

Functional outcomes (continence and potency recovery) also depend on several factors, not only influenced by the surgical approach. Thus, the risk of urinary incontinence after prostatectomy is highly influenced by patient characteristics such as age or previous prostate surgery, by surgeon experience, by apex reconstructions or by continence definitions (no pad versus safety pad). Main available series are limited by the impossibility of controlling surgical skills and individual surgeon factors. The integration of all potential predictive factors for both continence and potency recovery is mandatory before drawing strong conclusions, and no comparative has clearly included all these confounding factors.

Statistics help us to take into account several confounding factors when determining functional outcomes after radical prostatectomy. Many published studies did not state all these impacting factors limiting the power of their conclusions. Level of surgical experience, patient and disease characteristics, extension of nerve sparing surgery could play a part in differential outcomes and introduce interpretation biases when comparing surgical techniques. Finally, the only not debatable difference between the open radical prostatectomy and RARP techniques is the costs [26].

To conclude, although high level of evidence literature data report similar outcomes when comparing the primary endpoints of urinary continence, sexual function, and oncologic outcomes, RARP outperforms open radical prostatectomy in many ‘secondary’ areas including blood loss, operative adverse events, pain, postoperative complications, hospital stay. Robot-assisted surgery may also facilitate easier identification of nerve preservation planes and leads to an early potency recovery in low-risk prostate cancer cases. Recent data also confirm that safety of RARP in nonorgan confined disease with a wider dissection without hindering oncologic control.

This comprehensive review does not lead to a definitive recommendation for robotic-assistance approach, but is suggestive of improved perioperative parameters without hindering oncologic control.

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Acknowledgements

None.

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Financial support and sponsorship

None.

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Conflicts of interest

There are no conflicts of interest.

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REFERENCES AND RECOMMENDED READING

Papers of particular interest, published within the annual period of review, have been highlighted as:

  • ▪ of special interest
  • ▪▪ of outstanding interest
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REFERENCES

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Real-life comparisons between open and robotic approaches using a prospective, community-based registry

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First phase III randomised trial comparing RARP and open radical prostatectomy providing the highest level of evidence currently available

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Keywords:

continence; laparoscopy; potency; prostate neoplasm; prostatectomy; recurrence; robotic surgery

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