Effectiveness of extended pelvic lymphadenectomy in the survival of prostate cancer: a systematic review and meta-analysis

Robot-assisted radical prostatectomy using the novel hinotoriTM surgical robot system: initial experience and operation learning curve at a single institution

Background

The hinotoriTM surgical robot system (HSRS) is the first made-in-Japan robotic system used for radical prostatectomy. Here, we report initial results and describe our learning curve (skill development) implementing robot-assisted radical prostatectomy using HSRS (h-RARP).

Methods

Between November 2021 and December 2022, 97 patients who underwent h-RARP at our institution were enrolled in this study. We retrospectively evaluated the surgical outcomes of the initial cases using h-RARP, comparing those of RARP using da Vinci surgical robot system (d-RARP) in our institution. Furthermore, the learning curves of two surgeons with the highest number of h-RARP were analyzed. Patients treated by each surgeon were categorized into two groups: 1-15 cases (earlier group) and >15 cases (later group). Preoperative patient characteristics, operation parameters, and complication rates were compared between the two groups.

Results

In terms of surgical outcome, h-RARP was comparable to d-RARP. The procedures performed by the HSRS were successfully completed in all cases. There was no complication of grade 3 or higher. Comparing the two surgeons, surgeon 1, who had performed 40 d-RARP procedures, had time using robot system of the later group that was significantly shorter than that of the earlier group. However, for surgeon 2 with more than 100 d-RARP procedures, there was no statistically significant difference in time using robot system between groups. Other parameters showed no difference between earlier and later groups for the two surgeons.

Conclusions

Our results show that surgical outcomes of h-RARP are comparable to those of d-RARP during the initial experience of clinical application. In addition, the surgeons' learning curves for the total RARP experience suggest that the experience of d-RARP can carry over to performance using the novel HSRS.

Lymphoceles after pelvic lymph node dissection during robot-assisted radical prostatectomy

Background

Lymphoceles, lymph fluid-filled collections within the body lacking epithelial lining, are a common complication after pelvic lymph node dissection (PLND) during robot-assisted radical prostatectomy (RARP). In this study, we investigate the incidence of imaging confirmed symptomatic lymphoceles (SLC) in a centralized high-volume operating centre and assess predictive factors and treatment.

Methods

We retrospectively analysed the incidence, risk factors and treatment of a consecutive series of patients who underwent PLND during RARP between September 2018 and January 2021 in a specialised operation clinic. We compared baseline patients' characteristics and pathological data between men who developed an SLC and those who did not. A multivariable model for the occurrence of an SLC was created using predetermined, clinically relevant variables to investigate predictive factors.

Results

We analysed the records of 404 patients. The median follow-up length was 29 months. A total of 30 (7.4%) patients with an SLC were identified. The median time until SLC presentation was 12 weeks [interquartile range (IQR), 4-31 weeks], one-third of SLCs presented after 180 days. Percutaneous drainage was performed in 17 patients (57%). On multivariable analysis, only body mass index (BMI) significantly increased the odds of an SLC [per 5 odds ratio (OR) =1.7; 95% confidence interval (CI): 1.0-3.0, P=0.04].

Conclusions

SLCs present significant consequences, as more than half of patients with an SLC were treated with percutaneous drainage. Many patients presented later than the centralized surgeons' postoperative follow-up, a drawback of centralized care. An increased BMI was a significant predictor for SLC.

Different lymph node dissection ranges during radical prostatectomy for patients with prostate cancer: a systematic review and network meta-analysis

OBJECTIVE

The purpose of this network meta-analysis was to compare the effectiveness and adverse effects of limited, standard, extended, and super-extended pelvic lymph node dissection (PLND) following radical prostatectomy.

METHODS

This study followed the PRISMA 2020 statement. Clinical trials were searched from three electronic databases, including PubMed, the Cochrane Library, and Embase from the database's inception to April 5, 2022. The lymph node-positive rate, biochemical recurrence-free rate, lymphocele rate, thromboembolic rate, and overall complication rate were compared by meta-analysis. Data analyses were performed using R software based on the Bayesian framework.

RESULTS

Sixteen studies involving 15,269 patients were included. All 16 studies compared the lymph node-positive rate; 5 studies compared the biochemical recurrence-free rate; 10 studies compared the lymphocele rate; 6 studies compared the thromboembolic rate, and 9 studies compared the overall complication rate. According to Bayesian analysis, the lymph node-positive rate, lymphocele rate, and overall complication rate were significantly associated with the extension of the PLND range. The limited, extended, and super-extended PLND templates showed a similar but lower biochemical recurrence-free rate and a higher thromboembolic rate than the standard template.

CONCLUSIONS

The extension of the PLND range is associated with an elevated lymph node-positive rate; however, it does not improve the biochemical recurrence-free rate and correlates with an increased risk of complications, especially lymphocele. The selection of the PLND range in clinical practice should consider the oncological risk and adverse effects.

TRIAL REGISTRATION

PROSPERO (CRD42022301759).

Pelvic Lymphadenectomy May Not Improve Biochemical Recurrence-Free Survival in Patients with Prostate Cancer Treated with Robot-Assisted Radical Prostatectomy in Japan (The MSUG94 Group)

In this multicenter retrospective cohort study, we aimed to evaluate whether pelvic lymph node dissection (PLND) improved biochemical recurrence (BCR) in patients with prostate cancer (PCa) who underwent robot-assisted radical prostatectomy (RARP) in Japan. A multicenter retrospective cohort study of 3195 PCa patients undergoing RARP at nine institutions in Japan was conducted. Enrolled patients were divided into two groups: those who underwent RARP without PLND (non-PLND group) and those who underwent PLND (PLND group). The primary endpoint was biochemical recurrence-free survival (BRFS) in PCa patients who underwent PLND. We developed a propensity score analysis to reduce the effects of selection bias and potential confounding factors. Propensity score matching resulted in 1210 patients being enrolled in the study. The 2-year BRFS rate was 95.0% for all patients, 95.8% for the non-PLND group, and 94.3% for the PLND group (p = 0.855). For the all-risk group according to the National Comprehensive Cancer Network risk stratification, there were no significant differences between patients who did and did not undergo PLND. Based on the results of the log-rank study, PLND may be unnecessary for patients with PCa undergoing RARP.

Diagnostic Value of Radio-Guided Sentinel Node Detection in Patients with Prostate Cancer Undergoing Radical Prostatectomy with Modified-Extended Lymphadenectomy

Background. In many malignancies, sentinel lymph node dissection (SLND) is being used as a nodal staging tool. We prospectively evaluated the diagnostic value of radio-guided sentinel lymph node (SLN) detection in patients with prostate cancer (PCa). This study aimed to investigate the reliability of the radio-guided SLN detection technique for perioperative localization of LNs metastases as well as to map lymphatic drainage patterns of the prostate. Methods. Forty-three patients with intermediate- or high-risk cN0cM0 PCa at conventional imaging underwent radical prostatectomy with modified-extended pelvic lymph node dissection (mePLND). A day before the planned surgery, a Tc-99m nanocolloid was injected into the prostate under the control of transrectal ultrasonography (TRUS). Preoperative single-photon emission computed tomography (SPECT-CT) imaging and intraoperative gamma-probe were used to identify SLNs. All positive lesions were excised, followed by mePLND. The excised lymph nodes (LNs) were then submitted for histopathological examination, which was used as a reference for the calculation of diagnostic parameters of the SLN technique for SPECT-CT and the intraoperative gamma-probe. Results. In total, 119 SLNs were detected preoperatively (SPECT-CT) and 118 intraoperatively (gamma-probe). The study revealed that both SLN detection techniques showed a sensitivity of 90% and a specificity of 6.06%. The negative predictive value (NPV) was 66.67%. SLN technique would have correctly staged nine of 10 patients, which is the same result as in the case of limited LND. However, it allowed the removal of all metastatic nodes only in four of them. SLND would have comprised 69.7% of preoperatively detected LNs, and removed 13 out of 19 positive LNs (68.42%), respectively. Conclusions. Radio-guided SLND has a low diagnostic rate and is a poor staging tool. ePLND remains the gold standard in nodal metastases assessment in PCa. Our study indicates that lymphatic drainage of the prostate and actual metastasis routes may vary significantly.

Utility of Lymphadenectomy in Prostate Cancer: Where Do We Stand?

The purpose of this review is to summarize the current knowledge on lymph node dissection (LND) in prostate cancer (PCa) patients undergoing radical prostatectomy (RP). Despite a growing body of evidence, the utility and therapeutic and prognostic value of such an approach, as well as the optimal extent of LND, remain unsolved issues. Although LND is the most accurate staging procedure, the direct therapeutic effect is still not evident from the current literature, which limits the possibility of establishing clear recommendations. This indicates the need for further robust and adequately designed high-quality clinical trials.

Pelvic lymph node dissection in high-risk prostate cancer

INTRODUCTION

The therapeutic role of pelvic lymph node dissection (PLND) in prostate cancer (PCa) is unknown due to absence of randomized trials.

OBJECTIVE

to present a critical review on the therapeutic benefits of PLND in high risk localized PCa patients.

MATERIALS AND METHODS

A search of the literature on PLND was performed using PubMed, Cochrane, and Medline database. Articles obtained regarding diagnostic imaging and sentinel lymph node dissection, PLND extension, impact of PLND on survival, PLND in node positive "only" disease and PLND surgical risks were critically reviewed.

RESULTS

High-risk PCa commonly develops metastases. In these patients, the possibility of presenting lymph node disease is high. Thus, extended PLND during radical prostatectomy may be recommended in selected patients with localized high-risk PCa for both accurate staging and therapeutic intent. Although recent advances in detecting patients with lymph node involvement (LNI) with novel imaging and sentinel node dissection, extended PLND continues to be the most accurate method to stage lymph node disease, which may be related to the number of nodes removed. However, extended PLND increases surgical time, with potential impact on perioperative complications, hospital length of stay, rehospitalization and healthcare costs. Controversy persists on its therapeutic benefit, particularly in patients with high node burden.

CONCLUSION

The impact of PLND on biochemical recurrence and PCa survival is unclear yet. Selection of patients may benefit from extended PLND but the challenge remains to identify them accurately. Only prospective randomized study would answer the precise role of PLND in high-risk pelvis confined PCa patients.

Embryological Development and Topographic Anatomy of Pelvic Compartments-Surgical Relevance for Pelvic Lymphonodectomy

Background: The oncological outcome of surgery for the treatment of pelvic malignancies can be improved by performing pelvic lymphonodectomy. However, the extent and regions of lymph node harvest are debated and require profound knowledge of anatomy in order to avoid collateral damage. Methods: The embryological development and topographic anatomy of pelvic compartments in relation to pelvic lymphonodectomy for rectal, uterine, and prostate cancer are reviewed. Based on pre-dissected anatomical specimens, lymph node regions and drainage routes of the posterior and urogenital pelvic compartments are described in both genders. Anatomical landmarks are highlighted to identify structures at risk of injury during pelvic lymphonodectomy. Results: The ontogenesis of urogenital and anorectal compartments and their lymphatic supply are key factors for adequate lymphonodectomy, and have led to compartment-based surgical resection strategies. However, pelvic lymphonodectomy bears the risk of injury to somatic and autonomic nerves, vessels, and organs, depending on the regions and extent of surgery. Conclusion: Embryologically defined, compartment-based resection of pelvic malignancies and their lymphatic drainage routes are based on clearly delineated anatomical landmarks, which permit template-oriented pelvic lymphonodectomy. Comprehensive knowledge of pelvic anatomy, the exchange of surgical concepts between specialties, and minimally invasive techniques will optimize pelvic lymphonodectomy and reduce complications.

External validation of Memorial Sloan Kettering Cancer Center nomogram and prediction of optimal candidate for lymph node dissection in clinically localized prostate cancer

Introduction

The aim of our study was to evaluate the external validity of the online Memorial Sloan Kettering Cancer Center (MSKCC) nomogram as a predictor for pelvic lymph node invasion (LNI) in men who underwent radical prostatectomy (RP) with pelvic lymph node dissection (PLND).

Material and methods

The study cohort consisted of 679 men with clinically localized prostate cancer (PCa) who underwent RP with PLND between 2005 and 2017. The area under curve (AUC) of the receiver operator characteristic analysis was used to quantify the accuracy of MSKCC nomogram to predict LNI. The specificity, sensitivity and negative predictive value were calculated to assess LNI probability cut-off.

Results

A total of 81 of 679 patients had LNI (11.9%). The AUC of MSKCC nomogram was 79%. Using the cut-off value of 7% (sensitivity 88.9%, specificity 45.2% and NPV 96.8%) a PLND could be omitted in 41% (279/679) of men. However, 3.2% (9/279) of men with LNI would be missed. MSKCC nomogram showed good calibration characteristics and high net benefit at decision curve analysis.

Conclusions

MSKCC nomogram in patients with PCa undergoing PLND has 79% discriminated accuracy for prediction of LNI in our cohort. Using a 7% nomogram cut-off, roughly 40% of men would be spared PLND with minimal risk to miss LNI.

THE ROLE OF LYMPHADENECTOMY IN PROSTATE CANCER PATIENTS

Prostate cancer is one of the most important men's health issues in developed countries. For patients with prostate cancer a preoperative staging of the disease must be made. Involvement of lymph nodes could be assessed using imaging methods (CT or/and MRI), however, newer methods also exist (PET/CT, PSMA PET/CT). For some patients during radical prostatectomy a pelvic lymphadenectomy is recommended. Pelvic lymphadenectomy is indicated in intermediate- and high-risk group patients and with increased probability of lymph node invasion. The most used prediction tools for preoperative assessment of lymph nodes are Briganti and MSKCC nomograms and Partin tables. Pelvic lymphadenectomy can include different lymph nodes group, but extended lymphadenectomy is the recommended procedure. In 1-20% of patients, the lymph node invasion is present. Pelvic lymphadenectomy is primarily a diagnostic and staging method, and in minority of patients with positive lymph nodes it can be a curative method, too. In other patients with positive lymph nodes adjuvant therapy (radiotherapy and androgen deprivation therapy) can be beneficial.

Liquid Biopsy in Oligometastatic Prostate Cancer-A Biologist's Point of View

Prostate cancer (PCa) is the main cause of cancer-related mortality in males and the diagnosis, treatment, and care of these patients places a great burden on healthcare systems globally. Clinically, PCa is highly heterogeneous, ranging from indolent tumors to highly aggressive disease. In many cases treatment-generally either radiotherapy (RT) or surgery-can be curative. Several key genetic and demographic factors such as age, family history, genetic susceptibility, and race are associated with a high incidence of PCa. While our understanding of PCa, which is mainly based on the tools of molecular biology-has improved dramatically in recent years, efforts to better understand this complex disease have led to the identification of a new type of PCa-oligometastatic PCa. Oligometastatic disease should be considered an individual, heterogeneous entity with distinct metastatic phenotypes and, consequently, wide prognostic variability. In general, patients with oligometastatic disease typically present less biologically aggressive tumors whose metastatic potential is more limited and which are slow-growing. These patients are good candidates for more aggressive treatment approaches. The main aim of the presented review was to evaluate the utility of liquid biopsy for diagnostic purposes in PCa and for use in monitoring disease progression and treatment response, particularly in patients with oligometastatic PCa. Liquid biopsies offer a rapid, non-invasive approach whose use t is expected to play an important role in routine clinical practice to benefit patients. However, more research is needed to resolve the many existing discrepancies with regard to the definition and isolation method for specific biomarkers, as well as the need to determine the most appropriate markers. Consequently, the current priority in this field is to standardize liquid biopsy-based techniques. This review will help to improve understanding of the biology of PCa, particularly the recently defined condition known as "oligometastatic PCa". The presented review of the body of evidence suggests that additional research in molecular biology may help to establish novel treatments for oligometastatic PCa. In the near future, the treatment of PCa will require an interdisciplinary approach involving active cooperation among clinicians, physicians, and biologists.