Current controversies on the role of lymphadenectomy for prostate cancer

Progress of fluorescence imaging in lymph node dissection surgery for prostate and bladder cancer

Fluorescence imaging is a relatively new imaging method used to visualize different tissue structures to help guide intraoperative operations, which has potential advantages with high sensitivity and contrast compared to conventional imaging. In this work, we review fluorescent contrast agents and devices used for lymphatic system imaging. Indocyanine green is the most widely utilized due to its high sensitivity, specificity, low background fluorescence, and safety profile. In prostate and bladder cancer lymph node dissection, the complex lymphatic drainage can result in missed metastatic nodes and extensive dissection increases the risk of complications like lymphocele, presenting a significant challenge for urologists. Fluorescence-guided sentinel lymph node dissection facilitates precise tumor staging. The combination of fluorescence and radiographic imaging improves the accuracy of lymph node staging. Multimodal imaging presents new potential for precisely identifying metastatic pelvic lymph nodes.

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.

Differences in rates of pelvic lymph node dissection in National Comprehensive Cancer Network favorable, unfavorable intermediate- and high-risk prostate cancer across United States SEER registries

Background

The National Comprehensive Cancer Network (NCCN) guidelines recommend pelvic lymph node dissection (PLND) in NCCN high- and intermediate-risk prostate cancer patients. We tested for PLND nonadherence (no-PLND) rates within the Surveillance Epidemiology and End Results (2010-2015).

Materials and methods

We identified all radical prostatectomy patients who fulfilled the NCCN PLND guideline criteria (n = 23,495). Nonadherence rates to PLND were tabulated and further stratified according to NCCN risk subgroups, race/ethnicity, geographic distribution, and year of diagnosis.

Results

Overall, the no-PLND rate was 26%; it was 41%, 25%, and 11% in the NCCN intermediate favorable, intermediate unfavorable, and high-risk prostate cancer patients, respectively (p < 0.001). Over time, the no-PLND rates declined in the overall cohort and within each NCCN risk subgroup. Georgia exhibited the highest no-PLND rate (49%), whereas New Jersey exhibited the lowest (15%). Finally, no-PLND race/ethnicity differences were recorded only in the NCCN intermediate unfavorable subgroup, where Asians exhibited the lowest no-PLND rate (20%) versus African Americans (27%) versus Whites (26%) versus Hispanic-Latinos (25%).

Conclusions

The lowest no-PLND rates were recorded in the NCCN high-risk patients followed by NCCN intermediate unfavorable and favorable risk in that order. Our findings suggest that unexpectedly elevated differences in no-PLND rates warrant further examination. In all the NCCN risk subgroups, the no-PLND rates decreased over time.

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.

Feasibility and Optimal Time Point of [68Ga]Gallium-labeled Prostate-specific Membrane Antigen Ligand Positron Emission Tomography Imaging in Patients Undergoing Cytoreductive Surgery After Systemic Therapy for Primary Oligometastatic Prostate Cancer: Implications for Patient Selection and Extent of Surgery

Background

Prostate-specific membrane antigen (PSMA) targeted molecular imaging using positron emission tomography (PET) has significantly improved the diagnosis and treatment of prostate cancer (PCA).

Objective

To assess the feasibility and compare the diagnostic accuracy of [⁶⁸Ga]Ga-PSMA-11 PET images taken at baseline, before the initiation of systemic treatment and preoperative images, using histopathology after cytoreductive surgery as reference.

Design, setting, and participants

We identified 20 patients in our prospectively maintained database with primary oligometastatic PCA who underwent cytoreductive radical prostatectomy and superextended pelvic lymph node dissection after systemic therapy, who had baseline and preoperative [⁶⁸Ga]Ga-PSMA-11 PET imaging available.

Outcome measurements and statistical analysis

We performed a region-based analysis to determine the diagnostic accuracy of imaging, using pathology as a reference. Regions were predefined as prostate, internal iliac left/right, obturator left/right, external iliac left/right, common iliac left/right, and presacral.

Results and limitations

Sensitivity, specificity, negative predictive value (NPV), positive predictive value (PPV), and diagnostic effectiveness were, respectively, 95.65%, 78.22%, 98.39%, 57.89%, and 83.00% for baseline [⁶⁸Ga]Ga-PSMA-11 PET, compared to 56.52%, 98.05%, 88.30%, 89.66%, and 88.50% for preoperative [⁶⁸Ga]Ga-PSMA-11 PET. On a receiver operating characteristic analysis, the diagnostic accuracy of baseline [⁶⁸Ga]Ga-PSMA-11 PET with an area under the curve (AUC) of 0.87 (95% confidence interval [CI] 0.83–0.92) was significantly better than that of preoperative [⁶⁸Ga]Ga-PSMA-11 PET after systemic therapy with an AUC of 0.77 (95% CI 0.70–0.85, p = 0.01).

Conclusions

Baseline imaging, [⁶⁸Ga]Ga-PSMA-11 PET has significantly better diagnostic accuracy, sensitivity, and NPV than images obtained preoperatively, in systemically pretreated patients. If a patient is suitable for local treatment and complete resection of the residual tumor is intended, [⁶⁸Ga]Ga-PSMA-11 PET images taken prior to systemic therapy are significantly more accurate in selecting the relevant lymph nodes for resection.

Patient summary

We found that prostate-specific membrane antigen positron emission tomography (PSMA-PET) imaging used early, before hormonal therapy or chemotherapy, provides more accurate information about the spread of the disease, than if used immediately before surgery but after hormonal therapy or chemotherapy. Early use of PSMA-PET has the potential to improve therapy also at later stages of the disease.

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.

[It is unclear whether pelvic lymphadenectomy is of oncological benefit in prostate cancer]

Fossati's 2017 review questions the value of pelvic lymphadenectomy (pLA) in radical prostatectomy (RP) because available studies fail to show any oncological benefit. Our finding that no spread of metastatic lymph nodes (LN) has been demonstrated is based on registry data, clinical trials without evidence of pLA benefit and considerations of the genetic link between LN metastasis and distant metastases. The improved imaging with ⁶⁸GaPSMA-PET-CT facilitates the detection of metastases and thus the omission of pLA as diagnostic intervention, thereby avoiding typical complications. The question whether pLA, or a multimodal treatment concept, might benefit intermediate and high-risk patients can only be answered by an RCT which, above all, must consider the incompletely removed primary as a source of metastatic spread.

A novel robust nomogram based on peripheral monocyte counts for predicting lymph node metastasis of prostate cancer

Accurate methods for identifying pelvic lymph node metastasis (LNM) of prostate cancer (PCa) prior to surgery are still lacking. We aimed to investigate the predictive value of peripheral monocyte count (PMC) for LNM of PCa in this study. Two hundred and ninety-eight patients from three centers were divided into a training set (n = 125) and a validation set (n = 173). In the training set, the independent predictors of LNM were analyzed using univariate and multivariate logistic regression analyses, and the optimal cutoff value was calculated by the receiver operating characteristic (ROC) curve. The sensitivity and specificity of the optimal cutoff were authenticated in the validation cohort. Finally, a nomogram based on the PMC was constructed for predicting LNM. Multivariate analyses of the training cohort demonstrated that clinical T stage, preoperative Gleason score, and PMC were independent risk factors for LNM. The subsequent ROC analysis showed that the optimal cutoff value of PMC for diagnosing LNM was 0.405 × 109 l^-1 with a sensitivity of 60.0% and a specificity of 67.8%. In the validation set, the optimal cutoff value showed significantly higher sensitivity than that of conventional magnetic resonance imaging (MRI) (0.619 vs 0.238, P < 0.001). The nomogram involving PMC, free prostate-specific antigen (fPSA), clinical T stage, preoperative Gleason score, and monocyte-to-lymphocyte ratio (MLR) was generated, which showed a robust predictive capacity for predicting LNM before the operation. Our results indicated that PMC as a single agent, or combined with other clinical parameters, showed a robust predictive capacity for LNM in PCa. It can be employed as a complementary factor for the decision of whether to conduct pelvic lymph node dissection.

Pelvic lymph node dissection in prostate cancer: Laparoscopy is not dead

CONTEXT

Pelvic lymph node dissection (PLND) in localized prostate cancer is feasible through an open, laparoscopic or robot-assisted approach. Data comparing the three approaches is sparse.

OBJECTIVE

To perform a review in order to compare the effectiveness of the different PLND approaches.

ACQUISITION OF EVIDENCE

A search was performed including the following words: ("pelvic lymph node dissection") OR ("pelvic lymphadenectomy") AND ("French"[Language] OR "English"[Language]) AND ("1990"[Date-Publication]: "3000"[Date-Publication]) AND prostatectomy[Title]). Twenty-nine articles were finally included in the qualitative synthesis.

EVIDENCE SYNTHESIS

Laparoscopic pelvic lymph node dissection in prostate cancer is a minimally invasive procedure with a relatively short operative time, minimal blood loss, lower level of pain, shorter hospital stay, and fewer perioperative complications when compared to an open approach. This technique is more cost-effective than a robot-assisted approach.

CONCLUSION

Concerning the treatment of localized prostate cancer, laparoscopic pelvic lymph node dissection should be learned and applied by urologists.

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.

Diagnostic and therapeutic value of pelvic lymph node dissection in the fossa of Marcille in patients with clinically localized high-risk prostate cancer: Histopathological and molecular analyses

BACKGROUND

The optimal extent of lymph node dissection in radical prostatectomy has not been determined. Lymph nodes in the fossa of Marcille, which is an important pelvic lymphatic pathway and candidate for additional dissection, have not been evaluated at the molecular level. Here, we assessed by molecular analysis the presence of occult positive lymph nodes in the fossa of Marcille in patients with clinically localized high-risk prostate cancer.

METHODS

Fifty-two patients with clinically localized high-risk prostate cancer underwent pelvic lymph node dissection accompanied by robot-assisted radical prostatectomy. All nodal packets were dissected separately and grouped into right and left obturator, external and internal iliac regions (including common iliac region to ureter crossing), and fossa of Marcille. All lymph nodes were bisected and evaluated by histopathological or molecular analysis using a quantitative reverse transcription-polymerase chain reaction. The number of positive lymph nodes in the fossa of Marcille and the difference in detection rate were investigated using histopathological and molecular analyses. Perioperative complication rate and predictive factors for biochemical recurrence were evaluated.

RESULTS

In the molecular analysis, there were seven positive lymph nodes in the fossa of Marcille in three patients, which were coexistent with positive nodes in other regions. The detection rate of positive lymph nodes was significantly higher using molecular than histopathological analysis (P < .01). Perioperative complication rate within 90 days after the operation was 25.0% and no Clavien-Dindo grade ≥3 complication was confirmed. Detection of metastasis by histopathological and molecular analysis was a significant factor related to biochemical recurrence in the Cox proportional hazards regression model.

CONCLUSIONS

No case of positive lymph nodes in the fossa of Marcille that had skipped over other regions was confirmed. Additional lymph node dissection of fossa of Marcille did not lead to complete resection of molecularly positive lymph nodes.