Difference in Frequency and Distribution of Nodal Metastases Between Intermediate and High Risk Prostate Cancer Patients: Results of a Superextended Pelvic Lymph Node Dissection

The role and controversy of pelvic lymph node dissection in prostate cancer treatment: a focused review

Pelvic lymph node dissection (PLND) is commonly performed alongside radical prostatectomy. Its primary objective is to determine the lymphatic staging of prostate tumors by removing lymph nodes involved in lymphatic drainage. This aids in guiding subsequent treatment and removing metastatic foci, potentially offering significant therapeutic benefits. Despite varying recommendations from clinical practice guidelines across countries, the actual implementation of PLND is inconsistent, partly due to debates over its therapeutic value. While high-quality evidence supporting the superiority of PLND in oncological outcomes is lacking, its role in increasing surgical time and risk of complications is well-recognized. Despite these concerns, PLND remains the gold standard for lymph node staging in prostate cancer, providing invaluable staging information unattainable by other techniques. This article reviews PLND's scope, guideline perspectives, implementation status, oncologic and non-oncologic outcomes, alternatives, and future research needs.

Metastatic Sites' Location and Impact on Patient Management After the Introduction of Prostate-specific Membrane Antigen Positron Emission Tomography in Newly Diagnosed and Biochemically Recurrent Prostate Cancer: A Critical Review

CONTEXT

The introduction of prostate-specific membrane antigen positron emission tomography (PSMA-PET) had a substantial impact on the management of prostate cancer (PCa) patients with a stage migration phenomenon and consequent treatment changes.

OBJECTIVE

To summarise the role of PSMA-PET to define the burden of disease through an accurate location of metastatic site(s) in PCa patients, describing the most common locations at PSMA-PET in the primary staging and recurrence setting, and to assess the clinical impact in the decision-making process.

EVIDENCE ACQUISITION

A comprehensive nonsystematic literature review was performed in April 2022. Literature search was updated until March 2022. The most relevant studies have been summarised, giving priority to registered clinical trials and multicentre collaborations.

EVIDENCE SYNTHESIS

PSMA-PET showed higher diagnostic accuracy than conventional imaging both in newly diagnosed PCa and in recurrent disease. This greater accuracy led to a migration of a higher proportion of patients identified with metastatic disease. Bone metastases were reported as the most frequent site of metastatic spread in staging (up to 17%) and restaging (up to 18%). In staging, considering the suboptimal sensitivity in lymph node metastasis detection prior to radical surgery, PSMA-PET should be performed in patients with high risk or unfavourable intermediate risk only, and it is not recommended to routinely avoid pelvic lymph node dissection in case of a negative scan. In case of prostate-specific antigen relapse, PSMA-PET had higher diagnostic accuracy than other diagnostic procedures in the early detection of the sites of recurrence, thus influencing the therapy decision-making process.

CONCLUSIONS

PSMA-PET detects a higher number of lesions than conventional imaging or other PET radiotracers, especially metastatic lesions unseen with other modalities. The high diagnostic accuracy of PSMA-PET leads to a significant patient upstage and thus an impact in clinical management, even if the overall impact on cancer mortality is still to be assessed.

PATIENT SUMMARY

Prostate-specific membrane antigen positron emission tomography (PSMA-PET) identifies metastatic lesions with higher accuracy than conventional imaging, both in primary prostate cancer and during disease recurrence. Skeletal metastasis and extrapelvic lymph nodes are the most common sites of metastatic spread. The high accuracy of PSMA-PET in the detection of metastatic disease led to a significant impact on patient management, even if the overall impact on cancer mortality is still to be assessed.

Pelvic lymph node dissection in prostate and bladder cancers

Prostate cancer and bladder cancer accounts for approximately 13.5% and 3% of all male cancers and all newly diagnosed cancers (regardless sex), respectively. Thus, these cancers represent a major health and economic burden globally. The knowledge of lymph node status is an integral part of the management of any solid tumor. In the urological field, pelvic lymph node dissection (PLND) is of paramount importance in the diagnosis, management, and prognosis of prostate and bladder cancers. However, PLND may be associated with several comorbidities. In this narrative review, the most recent updates concerning the patterns and incidence of lymph node metastasis, the role of different imaging studies and nomograms in determining patients' eligibility for PLND, and the anatomical templates of PLND in urologic patients with bladder or prostate cancer will be discussed.

Influence of Biopsy Gleason Score on the Risk of Lymph Node Invasion in Patients With Intermediate-Risk Prostate Cancer Undergoing Radical Prostatectomy

Objective: To analyze the influence of biopsy Gleason score on the risk for lymph node invasion (LNI) during pelvic lymph node dissection (PLND) in patients undergoing radical prostatectomy (RP) for intermediate-risk prostate cancer (PCa).

Materials and Methods: We retrospectively analyzed 684 patients, who underwent RP between 2014 and June 2020 due to PCa. Univariable and multivariable logistic regression, as well as binary regression tree models were used to assess the risk of positive LNI and evaluate the need of PLND in men with intermediate-risk PCa.

Results: Of the 672 eligible patients with RP, 80 (11.9%) men harbored low-risk, 32 (4.8%) intermediate-risk with international society of urologic pathologists grade (ISUP) 1 (IR-ISUP1), 215 (32.0%) intermediate-risk with ISUP 2 (IR-ISUP2), 99 (14.7%) intermediate-risk with ISUP 3 (IR-ISUP3), and 246 (36.6%) high-risk PCa. Proportions of LNI were 0, 3.1, 3.7, 5.1, and 24.0% for low-risk, IR-ISUP1, IR-ISUP 2, IR-ISUP-3, and high-risk PCa, respectively (p < 0.001). In multivariable analyses, after adjustment for patient and surgical characteristics, IR-ISUP1 [hazard ratio (HR) 0.10, p = 0.03], IR-ISUP2 (HR 0.09, p < 0.001), and IR-ISUP3 (HR 0.18, p < 0.001) were independent predictors for lower risk of LNI, compared with men with high-risk PCa disease.

Conclusions: The international society of urologic pathologists grade significantly influence the risk of LNI in patients with intermediate- risk PCa. The risk of LNI only exceeds 5% in men with IR-ISUP3 PCa. In consequence, the need for PLND in selected patients with IR-ISUP 1 or IR-ISUP2 PCa should be critically discussed.

Cribriform architecture prostatic adenocarcinoma in needle biopsies is a strong independent predictor for lymph node metastases in radical prostatectomy

AIM

Lymph node metastases (pN1) at prostatectomy are infrequent but impact prognosis. Traditional prostate nomograms assess age, serum prostatic-specific antigen (PSA), clinical stage, and biopsy parameters to inform decisions on pelvic lymph node dissection. The impact of intraductal carcinoma (IDC) and cribriform pattern 4 (CC) on nodal metastases has yet to be explored.

METHODS

Five hundred forty three radical prostatectomy cases were reviewed for International Society of Urological Pathology (ISUP) grade, CC/IDC, T- and N-stage. Two hundred seventy five cases had matched biopsies with age, serum PSA, CC/IDC and ISUP grade recorded. The association of CC/IDC with pN1 in both prostatectomy and biopsy settings was assessed using Fisher's exact test, as well as univariable (UVA) and multivariable (MVA) logistic regression.

RESULTS

In 543 men in whom a prostatectomy was performed, a nodal dissection was also available in 340 (63%), and 37 (10.9%) of them had pN1 disease. ISUP grade, stage and CC/IDC were significantly associated with pN1 (p < 0.001). UVA regression showed grade (p < 0.001, odds ratio [OR]: 5.85), CC/IDC (p = 0.003, OR: 14.06) and T stage (p = 0.004, OR: 61.94) associated with pN1 as did MVA regression: grade (p = 0.010, OR: 2.81), CC/IDC (p = 0.015, OR: 5.12) and T stage (p = 0.016, OR: 30.38). In 275 patients with matched biopsies, a nodal dissection was performed in 197 (71.6%) and 20 (10.2%) patients had pN1 disease. On UVA regression, grade (p < 0.001, OR: 6.33), CC/IDC (p = 0.013, OR: 3.28), serum PSA (p = 0.001, OR: 1.08) and age (p = 0.047, OR: 1.07) were significant for pN1 at prostatectomy. All parameters including specifically grade (p = 0.007, OR: 5.35) and CC/IDC (p = 0.018, OR: 4.42) on biopsies predicted for pN1 by multivariate analysis.

CONCLUSION

CC/IDC in prostatectomy and biopsy significantly associates with pN1. Incorporation of CC/IDC status into preoperative nomograms may optimize patient selection for pelvic nodal dissection.

Standardized and Simplified Robot-assisted Superextended Pelvic Lymph Node Dissection for Prostate Cancer: The Monoblock Technique

BACKGROUND

Extended pelvic lymph node dissection (ePLND) remains the most accurate procedure for lymph node staging in intermediate- and high-risk prostate cancer (PCa) patients undergoing radical prostatectomy (RP). A superextended pelvic lymph node dissection (sePLND) can be considered in selected very-high-risk PCa patients.

OBJECTIVE

To demonstrate a reproducible robot-assisted technique for sePLND at the time of RP for PCa.

DESIGN, SETTING, AND PARTICIPANTS

From June 2016 to August 2019, 41 consecutive patients with localized PCa and very high risk for lymph node invasion (LNI) received a robot-assisted RP and a standardized 10-step monoblock ePLND, followed by a 5-step monoblock sePLND. Very high risk for LNI was defined as ≥30% risk for LNI, as calculated by the Briganti 2017 nomogram.

SURGICAL PROCEDURE

After performing the ePLND template resection (harvesting lymph nodes from the obturator region, external and internal iliac vessels, and common iliac vessels up to the ureter crossing), the 5-step monoblock sePLND approach was performed. The sePLND template was tailored to the common iliac vessels up to the aortic and caval bifurcation as well as the presacral region.

MEASUREMENTS

Lymph node yield, perioperative complications.

RESULTS AND LIMITATIONS

Overall, 41 patients received sePLND, reporting a median (interquartile range [IQR]) number of nodes removed of 23 (19-29). Median operative time (including RP, ePLND, and sePLND) was 256 min. Median preoperative prostate-specific antigen was 12 ng/mL (IQR 6.45-17.6). Disease stage pT <3 was found in 10 (24.4%) patients, pT3a in nine (22%) patients, pT3b in 21 (51.2%) patients, and pT4 in one (2.4%) patient. Of the treated patients, 54% revealed LNI: five (4.9%) in a solitary node, five (4.9%) in two to five nodes, and 12 (29.3%) in more than five nodes. Considering perioperative complications, three (7.3%) patients experienced Clavien I-II and four (9.7%) experienced Clavien ≥ III complications. Median hospital stay was 6 d. No patient underwent postoperative blood transfusion.

CONCLUSIONS

The 5-step sePLND approach is a reproducible and feasible technique for PCa patients at a very high risk of LNI.

PATIENT SUMMARY

In our study, we aimed to provide surgeons with a step-by-step technique for lymph node dissection, which aims to collect possibly metastatic lymph nodes of prostate cancer in an even more extended version ("superextended") than a standard ("extended") lymph node dissection.

68Ga-PSMA-11 PET has the potential to improve patient selection for extended pelvic lymph node dissection in intermediate to high-risk prostate cancer

INTRODUCTION

Radical prostatectomy with extended pelvic lymph node dissection (ePLND) is a curative treatment option for patients with clinically significant localised prostate cancer. The decision to perform an ePLND can be challenging because the overall incidence of lymph node metastasis is relatively low and ePLND is not free of complications. Using current clinical nomograms to identify patients with nodal involvement, approximately 75-85% of ePLNDs performed are negative. The aim of this study was to assess the added value of ⁶⁸Ga-PSMA-11 PET in predicting lymph node metastasis in men with intermediate- or high-risk prostate cancer.

METHODS

⁶⁸Ga-PSMA-11 PET scans of 60 patients undergoing radical prostatectomy with ePLND were reviewed for qualitative (visual) assessment of suspicious nodes and assessment of quantitative parameters of the primary tumour in the prostate (SUV_max, total activity (PSMA_total) and PSMA positive volume (PSMA_vol)). Ability of quantitative PET parameters to predict nodal metastasis was assessed with receiver operating characteristics (ROC) analysis. A multivariable logistic regression model combining PSA, Gleason score, visual nodal status on PET and primary tumour PSMA_total was built. Net benefit at each risk threshold was compared with five nomograms: MSKCC nomogram, Yale formula, Roach formula, Winter nomogram and Partin tables (2016).

RESULTS

Overall, pathology of ePLND specimens revealed 31 pelvic metastatic lymph nodes in 12 patients. ⁶⁸Ga-PSMA-11 PET visual analysis correctly detected suspicious nodes in 7 patients, yielding a sensitivity of 58% and a specificity of 98%. The area under the ROC curve for primary tumour SUV_max was 0.70, for PSMA_total 0.76 and for PSMA_vol 0.75. The optimal cut-off for nodal involvement was PSMA_total > 49.1. The PET model including PSA, Gleason score and quantitative PET parameters had a persistently higher net benefit compared with all clinical nomograms.

CONCLUSION

Our model combining PSA, Gleason score and visual lymph node analysis on ⁶⁸Ga-PSMA-11 PET with PSMA_total of the primary tumour showed a tendency to improve patient selection for ePLND over the currently used clinical nomograms. Although this result has to be validated, ⁶⁸Ga-PSMA-11 PET showed the potential to reduce unnecessary surgical procedures in patients with intermediate- or high-risk prostate cancer.

Extended pelvic lymph node dissection during radical prostatectomy: comparison between initial robotic experience of a high-volume open surgeon and his contemporary open series

BACKGROUND

The aim of this study was to evaluate intra- and perioperative outcomes of a single high volume open radical prostatectomy (ORP) surgeon, during his learning curve period for robot-assisted radical prostatectomy (RARP) and extended pelvic lymph node dissection (ePLND).

METHODS

The study included 264 intermediate-high risk prostate cancer patients, treated by ORP + ePLND or RARP + ePLND, prospectively collected. Descriptive statistics compared clinical and pathological variables between groups. Bivariate (Pearson) correlation analysis assessed the relationship between the number of lymph node (LN) removed, positive surgical margins (PSM), surgical time and the number of procedures performed per group.

RESULTS

pT stage and Gleason score (GS) were lower in RARP than in ORP group (both P=0.04), while PSM were more frequent in the RARP group (40% vs. 25%; P=0.02). However, PSM decreased with the increase of RARP procedures. The number of LNs removed was 25 and 22, in RARP and ORP group (P=0.03). However, LN+ rate did not differ between groups (11% vs. 16%; P=0.216). In the RARP group, overall surgical time and ePLND time decreased with the increase of surgical procedures (all P<0.001).

CONCLUSIONS

RARP requires significant learning curve to reduce operative room time and obtain PSM comparable to those of an ORP high-volume surgeon. On the contrary, the quality of ePLND during RARP seems to be not related to the number of procedures performed, allowing removal of a number of LNs that is clinically comparable to ORP.