Therapeutic Value of Standard Versus Extended Pelvic Lymph Node Dissection During Radical Prostatectomy for High-Risk Prostate Cancer

Japanese expert consensus on the standardization of robot-assisted pelvic lymph node dissection in urological surgery: Extent of pelvic lymph node and surgical technique

Pelvic lymph node dissection (PLND) is important for accurate staging and prognosis of prostate and/or bladder cancer. Several guidelines recommend extended PLND for patients with these cancers. However, the therapeutic benefits of extended PLND are unclear. One major reason is that the extent of PLND is not clearly defined. Thus, the working group for standardization of robot-assisted PLND, including nine experienced urologists for PLND in Japan, was launched in January 2023 by the Japanese Society of Endourology and Robotics. This study summarized the discussions to define the individual extent of PLND in urological surgery in a consensus meeting among these experienced urologists. The consensus meeting determined the extent of PLND based on arteries (veins) and anatomical membrane structures rather than a vague concept or approach toward PLND. This concept is expected to allow surgeons to implement the same extent of PLND. Finally, after a total of 10 online web conferences were held, we determined the extent of PLND for the obturator lymph node (LN) area, the internal iliac LN area, the external and common iliac LN area, and the presacral LN area according to the above rules. The extent of PLND suggested here currently does not have a clear therapeutic rationale. Therefore, the extent of our proposed PLND is by no means mandatory. We hope our definition of the extent of PLND will be supported by further evidence of therapeutic benefits for urologic cancers.

Japanese clinical practice guidelines for prostate cancer 2023

This fourth edition of the Japanese Clinical Practice Guidelines for Prostate Cancer 2023 is compiled. It was revised under the leadership of the Japanese Urological Association, with members selected from multiple academic societies and related organizations (Japan Radiological Society, Japanese Society for Radiation Oncology, the Department of EBM and guidelines, Japan Council for Quality Health Care (Minds), Japanese Society of Pathology, and the patient group (NPO Prostate Cancer Patients Association)), in accordance with the Minds Manual for Guideline Development (2020 ver. 3.0). The most important feature of this revision is the adoption of systematic reviews (SRs) in determining recommendations for 14 clinical questions (CQs). Qualitative SRs for these questions were conducted, and the final recommendations were made based on the results through the votes of 24 members of the guideline development group. Five algorithms based on these results were also created. Contents not covered by the SRs, which are considered textbook material, have been described in the general statement. In the general statement, a literature search for 14 areas was conducted; then, based on the general statement and CQs of the Japanese Clinical Practice Guidelines for Prostate Cancer 2016, the findings revealed after the 2016 guidelines were mainly described. This article provides an overview of these guidelines.

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.

Pelvic Lymph Node Dissection at Radical Prostatectomy for Intermediate Risk Prostate Cancer: Assessing Utility and Nodal Metastases Within a Statewide Quality Improvement Consortium

OBJECTIVE

To assess which patients with intermediate-risk PCa would benefit from a pelvic lymph node dissection (PLND) across the Michigan Urological Surgery Improvement Collaborative, given the discrepancy in recommendations. AUA guidelines for localized prostate cancer (PCa) state that PLND is indicated for patients with unfavorable intermediate-risk and high-risk PCa and can be considered in favorable intermediate-risk patients. NCCN guidelines recommend PLND when risk for nodal disease is ≥2%.

METHODS

Data regarding all robot-assisted radical prostatectomy (RARP) (March 2012-October 2020) were prospectively collected, including patient, and surgeon characteristics. Univariate and multivariate analyses of PLND rate and lymph node involvement (LN+) were performed.

RESULTS

Among 8,591 men undergoing RARP for intermediate-risk PCa, 80.2% were performed with PLND (n = 6883), of which 2.9% were LN+ (n = 198). According to the current AUA risk stratification system, 1.2% of favorable intermediate-risk PCa and 4.7% of unfavorable intermediate-risk PCa demonstrated LN+. There were also differences in the LN+ rates among the subgroups of favorable (0.0%-1.3%), and unfavorable (3.5%-5.0%) categories. Additional factors associated with higher LN+ rates include ≥50% cores positive, ≥35% involvement at any core, and unfavorable genomic classifier result, none of which contribute to the favorable/unfavorable subgroups.

CONCLUSION

These data support PLND at RARP for all patients with unfavorable intermediate-risk PCa. Our data also indicate patients with favorable intermediate-risk prostate cancer at greatest risk for LN+ are those with ≥50% cores positive, ≥35% involvement at any core, and/or unfavorable genomic classifier result.

Canine anal sac gland carcinoma with regional lymph node metastases treated with sacculectomy and lymphadenectomy: Outcome and possible prognostic factors

The staging system commonly used in canine anal sac gland carcinoma (ASGC) is a revised Tumour-Node-Metastasis (TNM) system published in 2007. This staging system consists in four stages and, for dogs with nodal metastases, the size of the metastatic lymph node (mLN) defines the N stage. However, we hypothesise that (1) the mLN size has no prognostic significance when the mLN can be excised, (2) a high number of mLNs is associated with poorer prognosis and (3) the measurement of the mLN on imaging is not reproducible. To investigate these hypotheses, medical records and diagnostic images of dogs with ASGC and mLN, treated with sacculectomy and lymphadenectomy, with or without chemotherapy, were reviewed. Interobserver variability for mLN measurement was assessed. Prognostic factors including mLN size and number were investigated. Time to documented progression (TDP) and disease-specific survival (DSS) were evaluated. Progression-free interval (PFI) was analysed with interval-censored data analysis. Fifty-seven dogs were included. The median PFI, TDP and DSS were 110 (95%CI 61.5-185.5), 196 (95%CI 162-283) and 340 days (95%CI 321-471), respectively. For measurement of the largest mLN, interobserver agreement was excellent but limits of agreement reached 39.7%. Neither the size of the largest mLN nor the use of adjuvant chemotherapy were associated with outcome. The number of mLNs was associated with outcome and having more than four mLNs was associated with shorter PFI (p < .001), TDP (p = .004) and DSS (p < .001). While mLN size measurement was not consistently reproducible and did not influence outcome in our cohort, number of mLNs did. Further studies are required for development of a revised staging system.

Association of lymph node yield with overall survival in patients with pathologically node negative prostate cancer

We investigated the association between lymph node yield (LNY) with overall survival (OS) and post-radical prostatectomy (RP) secondary treatments among men with pathologically node negative (pN0) prostate cancer. We reviewed the National Cancer Database for men with Gleason Grade Group 2 or higher prostate cancer treated with RP and had pathologically node-negative disease. LNY was modeled as a continuous and categorical variable grouped by quartiles of LNY. Secondary treatment was defined as the use of radiation or systemic therapy post-RP. Multivariable Cox proportional hazards and logistic regression models were used to test for an association of LNY with OS and secondary treatments, respectively. We identified 89,416 men with pN0 prostate cancer treated with RP from 2010-2015. LNY was associated with improved OS when modeled as a categorical and continuous variable. The third (6-9 nodes) and fourth (≥10 nodes) quartiles of LNY were associated with improved OS (HR 0.87, 95% CI 0.79-0.96, P = 0.006 and HR 0.88, 95% CI 0.79-0.98, P= 0.017, respectively) when compared with the lowest quartile of LNY (≤3 nodes) and the hazard of death decreased by 1% for each benign lymph node removed (HR 0.99, 95% CI 0.98-0.99, P= 0.022). Additionally, categorical and continuous LNY was associated with significantly less use of post-RP secondary treatments. Removal of additional negative lymph nodes was associated with improved OS and less secondary treatments in patients with pN0 prostate cancer. These data suggest that removing a higher quantity of lymph nodes provides more accurate staging and prognosis.

Evaluation of lymphovascular invasion as a prognostic predictor of overall survival after radical prostatectomy

OBJECTIVE

To assess the prognostic ability of lymphovascular invasion (LVI) as a predictor of overall survival (OS).

MATERIALS AND METHODS

We included 126,682 prostate cancer (CaP) cM0 patients who underwent radical prostatectomy with lymph node dissection between 2010 and 2015, within the National Cancer Database. Patients who received androgen deprivation therapy were included. Patients were divided into four sub-cohorts based on LVI and lymph node invasion (LNI) status: pL₀N₀, pL₁N₀, pL₀N₁, and pL₁N₁. Kaplan-Meier curves estimated OS and Cox-regression analysis tested the relationship between LVI and OS.

RESULTS

Median (IQR) age and PSA at diagnosis were 62 (57-66) years and 5.7 (4.5-8.9) ng/ml, respectively. Most patients had pT2 stage (68.5%), and pathological Gleason 3+4 (46.7%). 10.0% and 4.0% patients had LVI and LNI, respectively. Median follow-up was 42 months (27-58). At 5-years, OS was 96.5% in pL₀N₀ patients vs 93.1% pL₁N₀ patients vs 93.3% in pL₀N₁ patients vs 86.6% pL₁N₁ patients. LVI was an independent predictor of OS (hazard ratio [HR]:1.28). LVI showed interaction with LNI, as LVI was associated with a higher overall-mortality in patients with LNI (HR:1.66), than in patients without LNI (HR:1.22). (all P<0.0001) CONCLUSIONS: Our report highlights the detrimental impact of LVI on OS. Patients with LVI alone fared similarly to patients with LNI alone. Patients with both LVI and LNI had worse OS than those with only LVI or LNI, implying a synergetic detrimental interaction. Our findings demonstrate an important utility that LVI can provide in deciding patients' prognoses.

Oncological Outcome After Radical Prostatectomy without Pelvic Lymph Node Dissection for Localized Prostate Cancer: Follow-up Results in a Single Institution

The oncological benefit of pelvic lymph node dissection (PLND) is still debatable because data on clinical outcomes of radical prostatectomy (RP) without PLND are lacking. In this study, we reported oncological outcome in consecutive 146 patients who underwent RP without PLND. Although 27% of our patients developed biochemical recurrence, the estimated 5-year overall survival rates were 100%, 96.3%, and 95.7% in the low-, intermediate-, and high-risk groups, respectively. These data in our patients were not inferior to those in previous reports that investigated the survivals in patients who received PLND during RP. The therapeutic significance of PLND should be re-evaluated.

[Prophylactic nodal radiotherapy in prostate cancer]

The risk of lymph node invasion, in case of prostate cancer, increases with the clinical stage of the disease, the Gleason score of prostate biopsies and the value of PSA at diagnosis. Historically, beyond 15% risk of lymph node involvement, irradiation of the pelvic areas was performed with prostate radiotherapy (RT) to take into account the risk of occult lymph node metastasis in patients at risk, but the benefit of this therapeutic approach remains to be demonstrated. The data from surgical lymph node dissection seem to question the risk levels, the escalation of the dose on the prostate increases the survival without relapse, the contribution of image-guided radiotherapy, (IGRT) and modulation of intensity (IMRT), decreases the toxicity of pelvic RT. This article reviews the principles of prophylactic ganglion irradiation for prostate cancer and discusses its relevance, current uncertainties, and prospective trials.

Prostate-Specific Membrane Antigen Accumulation in Lower Extremity Lymphedema

Prostate-specific membrane antigen (PSMA) is overexpressed in a majority of prostate cancer cells, which has led to the development of radiolabeled small-molecule inhibitors of PSMA for molecular imaging and targeted radioligand therapy. Lu-labeled PSMA, with therapeutic β-emission and concomitant γ radiation, permits posttherapy imaging for the assessment of biodistribution and uptake in tumors and normal organs, as well as dosimetry. We report a patient with prostate cancer and metastatic lymph nodes-related lower extremity lymphedema, who presented with dermal backflow and soft-tissue uptake in the lower extremity on posttherapeutic whole body scan after intravenous Lu-PSMA treatment.

Cost-effectiveness comparison between neoadjuvant chemohormonal therapy and extended pelvic lymph node dissection in high-risk prostate cancer patients treated with radical prostatectomy: a multi-institutional analysis

The aim of the present study was to assess the cost-effectiveness of extended pelvic lymph node dissection (ePLND) compared to neoadjuvant chemohormonal therapy using gonadotropin-releasing hormone agonist/antagonist and estramustine. We retrospectively analyzed data within Michinoku Urological Cancer Study Group database containing 2971 PC patients treated with radical prostatectomy (RP) at four institutes between July 1996 and July 2017. We identified 237 and 403 high-risk patients who underwent RP and ePLND (ePLND group), and neoadjuvant chemohormonal therapy followed by RP and limited PLND (neoadjuvant group), respectively. The oncological outcomes and cost-effectiveness were compared between groups. Medical cost calculation focused on PC-related medication and adjuvant radiotherapy. Biochemical recurrence-free and overall survival rates in the neoadjuvant group were significantly higher than those in the ePLND group. Significantly higher number of patients progressed to castration-resistant PC in the ePLND group than in the neoadjuvant group. Background-adjusted multivariate Cox regression analysis using inverse probability of treatment weighting (IPTW) revealed that neoadjuvant chemohormonal therapy independently reduced the risk of biochemical recurrence after RP. The 5-year cost per person was significantly higher in the ePLND group than in the neoadjuvant group. Although the present study was retrospective, neoadjuvant chemohormonal therapy followed by RP as a concurrent strategy has potential to improve oncological outcome and cost-effectiveness.