Pelvic lymphadenectomy in prostate cancer

Simplified approach to the medial internal iliac region using a uretero-hypogastric nerve fascia development procedure for extended pelvic lymph node dissection during robot-assisted radical prostatectomy for high-risk prostate cancer

INTRODUCTION

Although several clinical guidelines for prostate cancer (PC) recommend extended pelvic lymph node dissection (ePLND) during radical prostatectomy for high-risk cases, there are several issues to consider, including certain technical aspects. A simplified approach to the medial internal iliac region and paravesical arteries has not been established. The uretero-hypogastric nerve fascia (UHF) envelopes the ureter, hypogastric nerve, and pelvic autonomic nerves. To preserve the UHF, it is possible to approach the medial side of the internal iliac vessels without injuring any important tissue. We analyzed technical feasibility and lymph node (LN) yields.

PATIENTS AND METHODS

After obtaining institutional review board approval, 265 high-risk PC patients with ePLND were identified. A da Vinci S or Xi robotic surgical system (Intuitive Surgical, Sunnyvale, CA, USA) was used. We divided the patients into conventional (non-UHF) method and modified (UHF) groups. The numbers of LNs removed, procedure-related complications, and surgical outcomes were analyzed.

RESULTS

The median number of LNs removed was 19.0 in the non-UHF group and 22.0 in the UHF group (p = 0.004). Significantly more LNs were removed from the internal iliac region in the UHF group (p = 0.042). There was no difference in overall operative, console, or LN dissection time, or the severe complication rate (Clavien-Dindo grade ≥ III), between the non-UHF and UHF groups.

CONCLUSIONS

Our simplified approach using the UHF development technique is technically feasible, has no major complications, and allows for the removal of significantly more LNs compared with the conventional method.

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 recurrence in high-risk prostate cancer following prostate-only radiotherapy

Introduction:

High-risk prostate cancer is the most common presentation at our institute among patients with non-metastatic prostate cancer. Traditionally, pelvic lymph nodes were given a prophylactic dose of radiotherapy while the prostate was given a curative dose of radiation. This study aims to evaluate patterns of failure in patients who had prostate-only radiation at our centre.

Materials and Methods:

All high-risk prostate cancer patients who underwent radical radiotherapy to prostate only since 2014 were retrospectively analysed. Local T stage, baseline prostate-specific antigen (PSA) and Gleason score were recorded. Bone scan and staging CT scan data were collected. Various dose levels prescribed to prostate were analysed. The follow-up records of these patients were assessed. Patients who failed in pelvic lymph nodes were recorded separately. Overall survival and failure-free survival were calculated using Kaplan–Meier curve.

Results:

One-hundred five patients fulfilling the inclusion criteria were analysed. Only three patients developed recurrence in pelvic lymph node following prostate-only radiotherapy (PORT). Five year overall survival was 77% while failure-free survival was 64%. Forty patients had a PSA failure after a median follow-up of 62 months.

Conclusions:

Most high-risk prostate cancer patients who progress following hormone therapy and PORT have metastases outside pelvis. Till further conclusive evidence is available PORT can be considered as a safe option.

Magnetic resonance imaging improves the prediction of tumor staging in localized prostate cancer

OBJECTIVES

The aim of this study was to investigate 3 Tesla multiparametric magnetic resonance imaging (mpMRI)-based predictors for the pretherapeutic T staging of prostate cancer and their accuracy.

METHODS

Consecutive patients with 3 Tesla mpMRI, positive systematic and MR-targeted biopsy, and subsequent radical prostatectomy (RPE) between 01/2016 and 12/2017 were included. MRI parameters such as measurable extraprostatic extension (EPE) (≥ 3 mm), length of (pseudo)capsular contact (LCC), invasion of neurovascular bundle (NVBI), and/or seminal vesicles lesion contact (SVC) or infiltration (SVI) were assessed and correlated to clinical and histopathological results.

RESULTS

136 men were included. In 76 cases, a pT2 stage was determined, in 29 cases a pT3a, and in 31 a pT3b stage. The positive and negative predictive values (PPV, NPV) for the detection of T3 by measurable EPE on MRI was 98% (CI 0.88-1) and 81% (CI 0.72-0.87). No visible NVBI was found in pT2 patients (NPV 100%; CI 0.95-1). ROC analysis for T3a prediction with LCC (AUC 0.81) showed a sensitivity of 87% and a specificity of 62% at a threshold of 12.5 mm (J = 0.485) and 93% and 58% at 11 mm (Jmax = 0.512). All patients with pT3a had a LCC > 5 mm. In case of pT3b, 29/31 patients showed a SVC (PPV 76%, CI 0.61-0.87; NPV 98%, CI 0.93-0.99), and 23/31 patients showed a SVI (PPV 100%, CI 0.86-1; NPV 93%, CI 0.87-0.96). EPE (p < 0.01), LCC (p = 0.05), and SVC (p = 0.01) were independent predictors of pT3.

CONCLUSIONS

MRI-measurable EPE, LCC, and SVC were reliable, independent, preoperative predictors for a histopathological T3 stage. A LCC ≥ 11 mm indicated a pT3a stage, whereas a LCC < 5 mm excluded it. On MRI, visible SVI or even SVC of the PCa lesion was reliable preoperative predictors for a pT3b stage.

Impact of Pelvic Lymph Node Dissection and Its Extent on Perioperative Morbidity in Patients Undergoing Radical Prostatectomy for Prostate Cancer: A Comprehensive Systematic Review and Meta-analysis

CONTEXT

Pelvic lymph node dissection (PLND) yields the most accurate staging in patients undergoing radical prostatectomy (RP) for prostate cancer (PCa), although it can be associated with morbidity.

OBJECTIVE

To systematically evaluate the impact of PLND extent on perioperative morbidity in patients undergoing RP. A new PLND-related complication assessment tool is proposed.

EVIDENCE ACQUISITION

A systematic review according to the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) was conducted. MEDLINE/PubMed, Scopus, Embase and Web of Science databases were searched to yield studies discussing perioperative complications following RP and PLND. The extent of PLND was classified according to the European Association of Urology PCa guidelines. Studies were categorized according to the extent of PLND. Intra- and postoperative complications were classified as "strongly," "likely," or "unlikely" related to PLND. Anatomical site of perioperative complications was recorded. A cumulative meta-analysis of comparative studies was conducted using Review Manager 5.3 (Cochrane Collaboration, Oxford, UK).

EVIDENCE SYNTHESIS

Our search generated 3645 papers, with 176 studies meeting the inclusion criteria. Details of 77 303 patients were analyzed. Of these studies, 84 (47.7%), combining data on 28 428 patients, described intraoperative complications as an outcome of interest. Overall, 534 (1.8%) patients reported one or more intraoperative complications. Postoperative complications were reported in 151 (85.7%) studies, combining data on 73 629 patients. Overall, 10 401 (14.1%) patients reported one or more postoperative complication. The most reported postoperative complication strongly related to PLND was lymphocele (90.6%). The pooled meta-analysis revealed that RP + limited PLND/standard PLND had a significantly decreased risk of experiencing any intraoperative complication (risk ratio [RR]: 0.55; p =  0.01) and postoperative complication strongly related to PLND (RR: 0.46; p =  <0.00001), particularly for lymphocele formation (RR: 0.52; p =  0.0003) and thromboembolic events (RR: 0.59; p =  0.008), when compared with extended/superextended PLND. The extent of PLND was confirmed to be an independent predictor of lymphocele formation (RR: 1.77; p <  0.00001).

CONCLUSIONS

The perioperative morbidity of PLND in patients undergoing RP and PLND for PCa significantly correlates with the extent of PLND. More standardized reporting of intra- and postoperative complications is needed to better estimate the direct impact of PLND extent on perioperative morbidity.

PATIENT SUMMARY

Pelvic lymph node dissection (PLND) is the most accurate method for staging in patients undergoing radical prostatectomy for prostate cancer, although it can be associated with complications. This study aims to systematically evaluate the impact of PLND extent on perioperative complications in these patients. We found that intra- and postoperative complications correlate significantly with the extent of PLND. A more rigorous assessment and thorough reporting of perioperative complications are recommended.

The Horse is at the Stable Door: Management of N1M0 Prostate Cancer

Pelvic lymph node involvement in prostate cancer is a significant poor prognostic factor with very little evidence on the optimal management options for these patients. It is estimated that lymph node-positive patients make up 12% of newly diagnosed prostate cancer and this figure is expected to rise with the advancement and increasing use of novel imaging. The controversy around this subgroup of patients is whether this is an intermediary stage before disseminated disease and hence amenable to curative treatment options. Systemic therapies have been the mainstay of treatment for these patients for decades, but in recent years, studies have emerged supporting the addition of local therapy. This review will focus on the current multimodal management approach for clinical and pathological lymph node-positive prostate cancer with a focus on radiotherapy options and aims to provide the rationale for a curative approach with a combination of local and systemic therapy.

Positive Association between Preoperative Total Testosterone and Lymph Node Invasion in Intermediate Risk Prostate Cancer

Introduction

Prostate cancer (PCa) patients who are classified into the intermediate risk category represent a heterogeneous population needing further preoperative risk assessment.

Objectives

To evaluate clinical total testosterone (TT) associations with lymph node invasion (LNI) in intermediate risk PCa.

Material and Methods

Between November 2014 and July 2016, intermediate risk PCa was assessed in 154 patients who underwent extended pelvic lymph node dissection if the risk of LNI was higher than 5%. Clinical factors associated with the risk LNI were investigated by the multinomial logistic regression model.

Results

The risk of LNI was assessed higher than 5% in 40.9% of cases of whom 15.5% had LNI. In the multivariate model, the risk of LNI was independently increased by prostate specific antigen (OR = 1.185; p = 0.021) and TT (OR = 1.004; p = 0.036). As a result, TT was an independent factor that associated with LNI because it increased the risk of LNI by 4% for each increment unit of TT.

Conclusion

Preoperative TT independently increased the risk of LNI in the intermediate risk class of PCa patients elected to radical prostatectomy and extended pelvic lymph node dissection. TT might be a useful preoperative factor for stratifying intermediate risk patients because of the positive association of TT with high grade tumors.

Prostate-specific antigen associates with extensive lymph node invasion in high-risk prostate cancer

OBJECTIVE

To evaluate clinical predictors of lymph node invasion (LNI) in patients with high-risk prostate cancer undergoing radical prostatectomy (RP) with extended pelvic lymph node dissection (ePLND).

METHODS

A contemporary cohort of 116 patients, who underwent ePLND during RP, was retrospectively evaluated. Patients were classified into 3 groups including cases without LNI (group 1), with 1 to 3 positive nodes (group 2; limited LNI), and with more than 3 positive nodes (group 3; extensive LNI). The multinomial logistic regression model (multivariate analysis) evaluated the risk of LNI.

RESULTS

Overall, 30 patients (25.9%) had LNI, which was limited in 17 cases (14.7%) and extensive in 13 subjects (11.2%). Median prostate-specific antigen (PSA) was higher in cases with limited (11.4 ng/mL) or extensive (23.5 ng/mL) LNI than cases without (7.3 ng/mL) and the difference was significant ( p <.0001). Median proportion of biopsy-positive cores was higher in limited (0.64) or extensive (0.54) LNI than cases without (0.34) and the difference was significant ( p < .0001). The distribution of other factors did not show any significant difference among the groups. On multivariate analysis, only higher values of PSA significantly affected the odds of extensive LNI when compared to cases without (odds ratio, 1.054; p = .005); PSA showed a fair discrimination power (area under the curve 0.792).

CONCLUSION

PSA was the only independent predictor of extensive LNI and could be an important preoperative factor for stratifying high-risk patients.

Bilateral lymph node micrometastases and seminal vesicle invasion associated with same clinical predictors in localized prostate cancer

AIM

To determine clinical factors associated with multiple bilateral lymph node micrometastases and seminal vesicle invasion (pT3b) in organ-confined prostate cancer (PCa).

METHODS

The study excluded patients under androgen deprivation, with lymph node involvement (cN1 status), and having undergone unilateral pelvic lymph node dissection (PLND) during radical prostatectomy (RP). Lymph node micrometastases were classified as unilateral (pN1m) and bilateral (pN1b). Analysis considered multivariate multinomial logistic regression models.

RESULTS

Between January 2013 and March 2015, 140 patients underwent PLND during RP. Lymph node micrometastases were detected in 28 cases (20%) including pN1m in 19 (13.6%) and pN1b in 9 (6.4%). Independent clinical predictors of pN1b included prostate-specific antigen (PSA, µg/L) >12.5 (odds ratio [OR] = 43.0), proportion of positive biopsy cores (PBC) >0.57 (OR = 6.7), and biopsy Gleason grade (bGG) >3 (OR = 7.5). Independent pT3b predictors included PSA>12.5 (OR = 3.8), PBC>0.57 (OR = 4.1), and bGG>3 (OR = 3.8).

CONCLUSIONS

In cN0 patients with localized PCa undergoing PLND, a nonnegligible rate of multiple lymph node micrometastases was detected (32.2%). In the natural history of PCa, there is a close association between pT3b and pN1b disease. Prostate cancer patients who are at high risk of extraglandular extension need selective pelvic staging by multiparametric magnetic resonance imaging to assess seminal vesicle invasion. Operated patients with pT3b and pNx status need close PSA monitoring because of the high probability of occult multiple bilateral lymph node micrometastases.

Optimization via specific fluorescence brightness of a receptor-targeted probe for optical imaging and positron emission tomography of sentinel lymph nodes

The optical properties of a receptor-targeted probe designed for dual-modality mapping of the sentinel lymph node (SLN) was optimized. Specific fluorescence brightness was used as the design criterion, which was defined as the fluorescence brightness per mole of the contrast agent. Adjusting the molar ratio of the coupling reactants, IRDye 800CW-NHS-ester and tilmanocept, enabled us to control the number of fluorescent molecules attached to each tilmanocept, which was quantified by H1 nuclear magnetic resonance spectroscopy. Quantum yields and molar absorptivities were measured for unconjugated IRDye 800CW and IRDye 800CW-tilmanocept (800CW-tilmanocept) preparations at 0.7, 1.5, 2.3, 2.9, and 3.8 dyes per tilmanocept. Specific fluorescence brightness was calculated by multiplication of the quantum yield by the molar absorptivity and the number of dyes per tilmanocept. It predicted that the preparation with 2.3 dyes per tilmanocept would exhibit the brightest signal, which was confirmed by fluorescence intensity measurements using three optical imaging systems. When radiolabeled with Ga68 and injected into the footpads of mice, the probe identified SLNs by both fluorescence and positron emission tomography (PET) while maintaining high percent extraction by the SLN. These studies demonstrated the feasibility of 800CW-tilmanocept for multimodal SLN mapping via fluorescence and PET-computed tomography imaging.

How can we predict lymphorrhoea and clinically significant lymphocoeles after radical prostatectomy and pelvic lymphadenectomy? Clinical implications

OBJECTIVE

• To identify clinical and pathological variables that may help clinicians in predicting, preventing and managing lymphorrhoea and clinically significant lymphocoeles (CSL), which are reported complications after pelvic lymphadenectomy (PLND) and retropubic radical prostatectomy (RRP).

PATIENTS AND METHODS

• We prospectively analysed 552 consecutive men with prostate cancer who underwent RRP and PLND (2006-2008). • All patients had detailed clinical and pathological data prospectively recorded in an electronic database. Drains were removed when the amount of lymph was < 20 mL in the previous 24 h. A CSL was defined as the presence of a symptomatic lymphocoele requiring treatment. Lymphorrhoea was defined as the total amount of lymph drained by the drains until their removal. • Univariable and multivariable logistic regression models were used to test the association between all the predictors (age, body mass index, American Society of Anesthesiologists score, prostate volume, clinical stage, number of LNs removed, surgeon, pathological T and N stage) and the presence of CSL. • Univariable and multivariable linear regression models were also used to test the association between the available predictors and lymphorrhoea.

RESULTS

• The median (range) number of LNs removed was 20 (1-63). Both linear and logistic multivariable regression analysis showed that the number of removed LNs and age were the only two statistically significant predictors of total amount of lymphorrhoea and CSL after RRP and PLND (both P < 0.01). • Specifically, the risk of developing a CSL increased by 5% for every LN removed. Similarly, every year of age increased the risk of having CSL by 5%. • The most informative thresholds for predicting CSL were 65 years of age and 20 LNs removed. • External iliac lymphadenectomy resulted in a higher associated risk of lymphorrhoea and CLS relative to obturator LN removal (P= 0.001 vs P= 0.1, respectively).

CONCLUSIONS

• There was a positive association between the number of LNs removed and age at RRP with the amount of lymphorrhoea and the risk of developing a CSL. • The most informative thresholds in predicting CSL were 65 years of age and 20 LNs removed. External iliac lymphadenectomy resulted in a higher risk of lymphorrhoea and CLS relative to obturator LN removal.