Role of lymph node dissection at the time of open or minimally invasive nephroureterectomy

Lymph Node Dissection in Upper Tract Urothelial Carcinoma: Current Status and Future Perspectives

PURPOSE OF REVIEW

This narrative review aims to evaluate the role of lymph node dissection (LND) in upper tract urothelial carcinoma (UTUC) and its implications for staging and management outcomes, as well as future perspectives.

RECENT FINDINGS

Multiple studies have demonstrated the limitations of conventional imaging techniques in accurately localizing lymph node metastasis (LNM) in UTUC. While 18F-fluorodeoxyglucose positron emission tomography with computed tomography (18FDG-PET/CT) shows promise for preoperative LNM detection, its specificity is low. Alternative methods such as choline PET/CT and sentinel lymph node detection are under consideration but require further investigation. Additionally, various preoperative factors associated with LNM hold potential for predicting nodal involvement, thereby improving nodal staging and oncologic outcomes of LND. Several surgical approaches, including segmental ureterectomy and robot-assisted nephroureterectomy, provide a possibility for LND, while minimizing morbidity. LND remains the primary nodal staging tool for UTUC, but its therapeutic benefit is still uncertain. Advances in imaging techniques and preoperative risk assessment show promise in improving LNM detection. Further research and multi-center studies are needed to comprehensively assess the advantages and limitations of LND in UTUC, as well as the long-term outcomes of alternative staging and treatment strategies.

The Stratification of Positive Lymph Nodes into pN1 and pN2 for Upper Urinary Tract Carcinoma is not Prognostically Significant

The 3^rd-7^th edition of the American Joint Committee on Cancer had 3 categories for positive lymph nodes (pN1-3) in upper urinary tract carcinoma. The 8^th edition removed pN3, defining pN1 as one lymph node with tumor deposit ≤ 2 cm and pN2 as a node with tumor deposit > 2 cm or metastases in multiple nodes. The aim of this study was to assess if the current pN categories impact survival in renal pelvic and ureteral carcinoma. Nephroureterectomies performed at our institution for primary upper urinary tract carcinoma between 2010-2019 were reviewed. Lymphadenectomy was performed in 73.3% of cases (151/206, median 9 nodes). Eighty-one (53.6%) patients were deceased at last review [pN0, 53 (44.5%); pN1-2, 28 (87.5%)]. There was no difference in overall or recurrence free survival between pN1 and pN2 with 5-year overall survival (95% confidence interval) of pN0, 60.7% (52.0-70.8%); pN1, 15.4% (4.3-35.2%); and pN2, 21.1% (8.8-40.3%). The metastatic deposit size threshold of 2 cm, number of positive lymph nodes, as well as extranodal extension did not correlate with overall or recurrence free survival. As such, pN1 and pN2 were grouped together with a 5-year overall survival of 18.8% (9.12-28.6%). The current stratification of upper urinary tract carcinoma into pN1 and pN2 does not provide prognostic information, and both yield a stage IV classification, regardless of pT or pM category. Therefore, we recommend further simplification of pN classification into one category for regional lymph node metastasis, irrespective of lymph node deposit size or number of positive lymph nodes.

Comparison of Perioperative Outcomes and Complications of Laparoscopic and Robotic Nephroureterectomy Approaches in Patients with Upper-Tract Urothelial Carcinoma

BACKGROUND

For medical institutions without robotic equipment, it remains uncertain whether laparoscopic radical nephroureterectomy (LNU) can achieve results similar to those of robotic surgery for the treatment of upper tract urothelial carcinoma (UTUC). This meta-analysis aimed to compare the efficacy and safety of robot-assisted radical nephroureterectomy (RANU) with that of LNU using a large sample size of patients.

METHODS

A systematic meta-analysis was performed using data (available to May 2022) acquired from multiple scientific databases. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) and Assessing the Methodological Quality of Systematic Reviews (AMSTAR) guidelines, according to the protocols registered with PROSPERO (CRD42021264046), were followed to perform this cumulative analysis.

RESULTS

Nine high-quality studies were included in this analysis, considering factors such as operative time (OT), estimated blood loss (EBL), length of hospital stay (LOS), positive surgical margins (PSM), and complications. Statistical indicators revealed no significant differences between the RANU and LNU groups in terms of OT (weighted mean difference [WMD] 29.41, 95% confidence interval [CI] -1.10 to 59.92; p = 0.22), EBL (WMD -55.30, 95% CI -171.14 to 60.54; p = 0.13), LOS (WMD -0.39, 95% CI -1.03 to 0.25; p = 0.12), PSM (odds ratio [OR] 1.22, 95% CI 0.44-3.36; p = 0.17], or complications (OR 0.91, 95% CI 0.49-1.69; p = 0.13).

CONCLUSION

The meta-analysis showed that the perioperative and safety indicators of both RANU and LNU were similar and both showed favorable outcomes in UTUC treatment. However, some uncertainties remain in the implementation and selection of lymph nodes for dissection.

Optimizing Lymph Node Dissection at the Time of Nephroureterectomy for High-risk Upper Tract Urothelial Carcinoma

Lymph node dissection (LND) has prognostic and possible therapeutic benefits in the management of high-risk upper tract urothelial carcinoma. However, LND use is low and difficult to monitor, so it is not easy to study LND outcomes and the true rate of use. Prespecified templates for complete node dissection and detailed reporting are imperative to critically assess the benefits of LND in future studies. Barriers to LND use may include fear of complications and difficulty in predicting which patients have high-risk disease. Methods to improve LND implementation include the use of strict templates with descriptive pathology reporting, nomograms for preoperative risk stratification, and LND as a quality indicator to monitor rates of use and guideline concordance. PATIENT SUMMARY: For patients with high-risk cancer of the upper urinary tract, removal of lymph nodes during surgery improves identification of the cancer stage and may have a therapeutic effect too. Further studies are needed to confirm potential therapeutic benefits.

Oncological outcomes of retroperitoneal lymph node dissection during retroperitoneal laparoscopic radical nephroureterectomy for renal pelvic or upper ureteral tumors: Matched-pair analysis

OBJECTIVES

To investigate the oncological outcomes and recurrence patterns of clinically node-negative patients with renal pelvic and/or upper or middle ureteral tumors after a template-based retroperitoneal lymph node dissection (RPLND) in conjunction with retroperitoneal laparoscopic radical nephroureterectomy (LRNU).

METHODS

A total of 283 patients who received LRNU with and without RPLND at three Japanese institutions were enrolled. The template of RPLND included the renal hilar and paraaortic lymph nodes (LNs) (left side) and renal hilar, paracaval, retrocaval, and intra-aortocaval LNs (right side). The LNs and kidneys were removed en bloc. The primary endpoint was set as recurrence-free survival. All RPLND cases were matched one-to-one with no RPLND cases using a propensity score matching approach, and 47 matched pairs were included in analyses.

RESULTS

Compared to the control group, significant differences were not observed in the RPLND group in terms of operation time, blood loss, postoperative complication rate, and pathological findings. The estimated five-year recurrence-free survival was significantly higher in the RPLND group (86.8%) compared to the group without RPLND (64.2%) (p = 0.014). The estimated five-year cancer-specific survival showed a similar tendency; however, it did not reach a statistically significant difference (87.5% vs 71.3%, respectively; p = 0.168). As for the first recurrence site, the RPLND group showed a lower incidence of distant recurrence, while a significant difference was not observed in the rate of regional LN recurrence.

CONCLUSION

This study suggests that a template-based RPLND in conjunction with retroperitoneal LRNU efficiently improves the recurrence-free survival by reducing distant recurrences.

Complications and their management following retroperitoneal lymph node dissection in conjunction with retroperitoneal laparoscopic radical nephroureterectomy

OBJECTIVES

To describe the detailed perioperative complications and their management after retroperitoneal lymph node dissection with retroperitoneal laparoscopic radical nephroureterectomy for patients with upper tract urothelial carcinoma at three institutions.

METHODS

Retroperitoneal lymph node dissection was performed on patients with upper tract urothelial carcinoma located at the pelvis and/or upper or middle ureter, and its template included the renal hilar and para-aortic lymph nodes (left side) and the renal hilar, paracaval, retrocaval, and intra-aortocaval lymph nodes (right side). The lymph nodes and kidneys were removed en bloc. The primary endpoint was postoperative complication rates, and the secondary endpoints were intraoperative findings and chylous leakage management. The associations of retroperitoneal lymph node dissection with postoperative complications were examined using logistic regression with propensity score techniques.

RESULTS

Eighty-eight (31%) and 195 (69%) patients underwent and did not undergo retroperitoneal lymph node dissection, respectively. There was no significant difference in postoperative complications and other perioperative findings in the entire cohort, except for prolonged operation time. Retroperitoneal lymph node dissection was not statistically significantly associated with total and serious complications in propensity score analyses. Postoperative chylous leakage could be conservatively managed even though it is common in patients with retroperitoneal lymph node dissection (14/88 (16%)). The incidence of chylous leakage was significantly lower in patients whose lymphatic vessels were meticulously clipped completely during retroperitoneal lymph node dissection (5.3% vs 24%; P = 0.017).

CONCLUSION

There was no association between retroperitoneal lymph node dissection with laparoscopic radical nephroureterectomy and postoperative complications. However, chylous leakage is often observed after retroperitoneal lymph node dissection and careful management is highly required. The use of clips during retroperitoneal lymph node dissection is recommended to minimize chylous leakage risk.