Sentinel node detection in renal cell carcinoma. A feasibility study for detection of tumour-draining lymph nodes

The Current Role of Lymph Node Dissection in Nonmetastatic Localized Renal Cell Carcinoma

PURPOSE

To explore the current role of lymph node dissection (LND) in the management of nonmetastatic localized renal cell carcinoma (RCC).

BACKGROUND

There is currently no proven benefit of LND in the setting of RCC, and its role remains controversial because of conflicting evidence. Patients who may benefit from LND are those at greatest risk of nodal disease, but the tools used to predict nodal involvement are limited due to unpredictable retroperitoneal lymphatics. The indications, templates, and extent of LND are also not standardized, adding to the ambiguity of current guidelines surrounding its use.

EVIDENCE ACQUISITION

A PubMed search of the literature from January 2017 to December 2022 was conducted using the search terms "renal cell carcinoma" or "renal cancer" in combination with "lymph node dissection" or "lymphadenectomy". Case studies and editorials were excluded, whereas studies investigating the therapeutic effect of LND were classified as either demonstrating a benefit or no benefit. References of the studies and review articles were also searched for notable studies and findings that were outside the five-year literature search. The studies in this review were restricted to the English language.

RESULTS

Only a number of studies in recent years have found an association between the extent of LND and increased survival. Most studies do not indicate an associated benefit, and some even suggest a negative effect on survival. Most of these studies are retrospective.

CONCLUSION

The therapeutic value of LND in RCC is still unclear, and although prospective data are needed, its declining rates and emerging new therapies make this unlikely. A better understanding of renal lymphatics and improved detection of nodal disease may help determine the role of LND in nonmetastatic localized RCC.

Technical advances in the surgical management of Wilms tumors in children

Surgery is one of the cornerstones of Wilms tumor treatment. In this article, we present technical advancements that are finding their way into the armamentarium of pediatric cancer surgeons. We discuss the current approaches, challenges, opportunities, and future directions of minimally invasive surgery (laparoscopic and robotics), image-guided surgery, and fluorescence-guided surgery. Furthermore, we discuss the use of intraoperative ultrasonography, as well as the use of new techniques to improve the quality of lymph node sampling.

Characteristics and Outcome of Children with Renal Cell Carcinoma: A Narrative Review

Pediatric renal cell carcinoma (RCC) is a rare type of kidney cancer, most commonly occurring in teenagers and young adolescents. Few relatively large series of pediatric RCC have been reported. Knowledge of clinical characteristics, outcome and treatment strategies are often based on the more frequently occurring adult types of RCC. However, published pediatric data suggest that clinical, molecular and histological characteristics of pediatric RCC differ from adult RCC. This paper summarizes reported series consisting of ≥10 RCC pediatric patients in order to create an up-to-date overview of the clinical and histopathological characteristics, treatment and outcome of pediatric RCC patients.

Survival benefit with extended lymphadenectomy for advanced renal malignancy: A population-based analysis

Objective

We used population-based data to examine the possible benefit of extended lymphadenectomy for patients with renal malignancy in the setting of more advanced disease.

Methods

The Surveillance, Epidemiology, and End Results (SEER) database was utilized to identify non-metastatic, T3-T4 renal cancer patients from 2004–2015 treated with removal of ≥1 lymph node at the time of nephrectomy. Non-parametric bivariate statistics were used to assess associations between covariates of interest and extended lymphadenectomy (≥10 lymph nodes removed). Cancer-specific survival (CSS) and overall survival (OS) benefit was evaluated using Kaplan–Meier analysis.

Results

Of the 4397 patients identified, 816 (18.6%) underwent extended lymphadenectomy. For patients with T3a disease, 5-year CSS and OS benefit with extended lymphadenectomy did not reach statistical significance (CSS: hazard ratio [HR] 0.98, 95% confidence interval [CI] 0.77–1.24; OS: HR 0.96, 95% CI 0.77–1.20). Conversely, for those with T3b-T3c disease, extended lymphadenectomy led to statistically significant improvements in both 5-year CSS and OS compared to non-extended lymphadenectomy (CSS: HR 0.78, 95% CI 0.61–0.99; OS: HR 0.72, 95% CI 0.58–0.90). Finally, for those with T4 disease, use of extended lymphadenectomy had OS benefit after 5 years (OS: HR 0.51, HR 0.29–0.90, p = 0.02).

Conclusion

Based on population-level data, extended lymphadenectomy was associated with improved survival in select patients with advanced renal malignancy treated with surgical nephrectomy. Understanding the basis of these real-world findings in the face of conflicting randomized trial results will be key, moving forward.

Sentinel Lymph Node Biopsy in Renal Tumors: Surgical Technique and Safety

OBJECTIVE

To understand uncertainties and knowledge gaps regarding lymphatic drainage in renal tumors, we performed 2 prospective studies to demonstrate regional lymph node (LN) drainage with sentinel lymph node (SN) imaging and biopsy. Here, we report the technique and perioperative safety of retroperitoneal SN dissection with different surgical approaches.

METHODS

Seventy three patients from the 2 trials were included in the analysis. Patients had cT1-2N0M0 renal tumors (</=10 cm) and underwent nephrectomy (46/63%) or partial nephrectomy (27/37%) with SN dissection after intraoperative detection with a γ-probe, and locoregional LND. Twenty-nine of 73 patients had open surgery, 27 of 73 laparoscopic, and 17 of 73 robot-assisted laparoscopic (partial) nephrectomy. Surgery time, intraoperative adverse events (AE) according to CTCAE 5.0, and postoperative AE according to Clavien-Dindo (CD) were retrospectively assessed.

RESULTS

There were no grade ≥3 intraoperative CTCAE 5.0 AEs. Postoperative AE rate was 16.4% of which 7 (9.6%) were CD grade 1-2 and 5 (6.8%) were 3a grade complications. There were no statistically significant differences between presence of AE, CD grade, and surgical modality (P = .27 and P = .13, respectively). Blood loss was a median of 550 ml (IQR 200-900 ml) and 225 (IQR 42-751 ml) for partial nephrectomy (PN) and radical nephrectomy, respectively. Length of the procedure was 170 minutes (IQR 149-184 minutes), 155 minutes (IQR 130-177 minutes) 180 minutes (IQR 162-202 minutes) in open, laparoscopic, and robot-assisted procedures, respectively.

CONCLUSION

The addition of retroperitoneal SN dissection combined with locoregional LND during (partial) nephrectomy is surgically safe. Complication rate is low and does not differ between surgical approaches.

Templates of Lymph Node Dissection for Renal Cell Carcinoma: A Systematic Review of the Literature

Background: The role of lymph node dissection (LND) for renal cell carcinoma (RCC) is controversial. Notably, the conflicting evidence on the benefits and harms of LND is inherently linked to the lack of consensus on both anatomic templates and extent of lymphadenectomy. Herein, we provide a detailed overview of the most commonly dissected templates of LND for RCC, focusing on key anatomic landmarks and patterns of lymphatic drainage.

Methods: A systematic review of the English-language literature was performed without time filters in July 2018 in accordance to the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) statement recommendations. The primary endpoint was to summarize the most commonly dissected templates of LND according to the side of RCC.

Results: Overall, 25 studies were selected for qualitative analysis. Of these, most were retrospective. The LND template was heterogeneous across studies. Indications and extent of LND were either not reported or not standardized in most series. The most commonly dissected template for right-sided tumors included hilar, paracaval, and precaval nodes, with few authors extending the dissection to the inter-aortocaval, retrocaval, common iliac or pre/paraaortic nodes. Similarly, the most commonly dissected template for left-sided tumors encompassed the renal hilar, preaortic and paraaortic nodes, with few authors reporting a systematic dissection of inter-aortocaval, retro-aortic, common iliac, or para-caval nodes.

Conclusions: In light of the unpredictable renal lymphatic anatomy and the evidence from available prospective mapping studies, the extent of the most commonly dissected templates might be insufficient to catch the overall anatomic pattern of lymphatic drainage from RCC.

An analysis of SPECT/CT non-visualization of sentinel lymph nodes in renal tumors

Background

Sentinel lymph node biopsy (SLNB) after intratumoral injection of ^99mTc labeled nanocolloid and imaging with scintigraphy and SPECT/CT in renal tumors is feasible. However, sentinel lymph node (SN) non-detection rate with scintigraphy and SPECT/CT is high. The aim of the study was to determine factors affecting non-visualization (NV) of SN imaging in renal tumors. Seventy-eight patients with cT1–3 renal tumors received intratumoral injection of 225 MBq ^99mTc-labeled nanocolloid 1 day before (partial) nephrectomy. Radiotracer injection was followed by anterioposterior and lateral scintigraphy in combination with SPECT/CT 20 min and 2–4 h after. Surgical treatment of the tumor with sentinel lymph node biopsy by aid of γ-probe and-camera was performed the next day. Scintigraphy and SPECT/CT images were evaluated and patient, tumor, and procedure characteristics were collected for 73 eligible patients used in uni- and multivariable analysis of a potential association with NV.

Results

A total of 80 (mean 1.1, IQR 0–2, max 6) sentinel lymph nodes in 46 patients were detected with scintigraphy and SPECT/CT. Preoperative visualization rate and intraoperative detection rate was 63% [95% CI 50–73%] and 61% [95% CI 49–72%], respectively. In uni- and multivariable analysis, the only factor associated with non-visualization was age, showing higher odds of non-visualization with higher age.

Conclusion

Our study demonstrated that non-visualization of SNs in renal tumors is relatively high and is associated with patient age. Furthermore, kidneys and also its tumors are highly vascularized which may cause a wash-out effect that could be identified with decreased kidney-liver ratios. However, in our data, the effect was statistically inconclusive. Further studies are needed to improve visualization and standardize the procedure of SLNB in renal tumors. The percentage of NV limits the use of SLNB for research and clinical purposes in renal cancer.

Electronic supplementary material

The online version of this article (10.1186/s13550-018-0460-y) contains supplementary material, which is available to authorized users.

The side and the location of the primary tumor does not affect the probability of lymph node invasion in patients with renal cell carcinoma

PURPOSE

To evaluate the role of side and location of the primary renal cell carcinoma (RCC) on the risk of lymph node invasion (LNI) and/or nodal progression (NP) during follow-up.

MATERIALS AND METHODS

We evaluated 2485 patients with unilateral RCC, surgically treated in a single tertiary care referral center. Outcomes were LNI at surgery and/or NP during follow-up. We studied if RCC side (left vs. right) and location (upper vs. middle vs. hilar vs. lower area vs. more than one area) affected the probability of LNI and/or NP at follow-up.

RESULTS

Overall, 43 and 15% of patients underwent lymph node dissection and had LNI at surgery, respectively. During follow-up, 2.2% of patients had NP. Higher rates of LNI and NP were observed for patients with primary tumor located in more than one anatomical kidney area relative to patients with tumor in a single area (upper 11% vs. middle 10% vs. hilar 0%, vs. lower 12% vs. more than one area 26%, p < 0.01). cM1, cN1, pT2/pT3/pT4 disease and Fuhrman grade 3/4 were independent predictors of the study outcome (all p ≤ 0.01). Neither the RCC side nor the location reached the independent predictor status (all p > 0.1).

CONCLUSIONS

Patients with single-side and more than one anatomical kidney area affected by RCC have higher rate of LNI at surgery and/or NP at follow-up. Neither side nor location of primary RCC tumor is related to the risk of harboring LNI at surgery and/or developing NP at follow-up.

Sentinel lymph node imaging in urologic oncology

Lymph node (LN) metastases in urological malignancies correlate with poor oncological outcomes. Accurate LN staging is of great importance since patients can benefit from an optimal staging, accordingly aligned therapy and more radical treatments. Current conventional cross-sectional imaging modalities [e.g., computed tomography (CT) and magnetic resonance imaging (MRI)] are not accurate enough to reliably detect early LN metastases as they rely on size criteria. Radical lymphadenectomy, the surgical removal of regional LNs, is the gold standard of invasive LN staging. The LN dissection is guided by anatomic considerations of lymphatic drainage pathways of the primary tumor. Selection of patients for lymphadenectomy heavily relies on preoperative risk stratification and nomograms and, as a result a considerable number of patients unnecessarily undergo invasive staging with associated morbidity. On the other hand, due to individual variability in lymphatic drainage, LN metastases can occur outside of standard lymphadenectomy templates leading to potential understaging and undertreatment. In theory, metastases from the primary tumor need to pass through the chain of LNs, where the initial node is defined as the sentinel LN. In theory, identifying and removing this LN could lead to accurate assessment of metastatic status. Radiotracers and more recently fluorescent dyes and superparamagnetic iron oxide nanoparticles (SPION) are injected into the primary tumor or peritumoral and the sentinel LNs are identified intraoperatively by a gamma probe, fluorescent camera or a handheld magnetometer. Preoperative imaging [e.g., single-photon emission computed tomography (SPECT)/CT or MRI] after tracer injection can further improve preoperative planning of LN dissection. While sentinel LN biopsy is an accepted and widely used approach in melanoma and breast cancer staging, its use in urological malignancies is still limited. Most data published so far is in penile cancer staging since this cancer has a typical echelon-based lymphatic metastasizing pattern. More recent data is encouraging with low false-negative rates, but its use is limited to centers with high expertise. Current guidelines recommend sentinel LN biopsy as an accepted alternative to modified inguinal lymphadenectomy in patients with pT1G2 disease and non-palpable inguinal LNs. In prostate cancer, a high diagnostic accuracy could be demonstrated for the sentinel approach. Nevertheless, due to lack of data or high false-negative rates in other urological malignancies, sentinel LN biopsy is still considered experimental in other urological malignancies. More high-level evidence and longitudinal data is needed to determine its final value in those malignancies. In this manuscript, we will review sentinel node imaging for urologic malignancies.

The contemporary role of lymph node dissection in the management of renal cell carcinoma

The appropriate role of lymph node dissection (LND) in the management of patients with renal cell carcinoma (RCC) is still a matter of debate. There is ample evidence that LND is the most accurate modality for staging the regional lymph nodes (LNs), which may harbor metastatic disease in greater than one-third of patients with high-risk RCC. The presence of LN metastases is an independent negative prognostic factor in this disease and accurate determination of LN status not only helps with patient counselling regarding prognosis and tailoring of postoperative surveillance schedules, but it also identifies patients at high risk of systemic disease recurrence who may qualify for clinical trials of adjuvant systemic therapies. Meanwhile, the therapeutic value of LND has been brought into question by a randomized trial (European Organisation for Research and Treatment of Cancer; EORTC 30881) that showed no difference in progression-free or overall survival between patients who were treated with radical nephrectomy (RN) and LND and those treated with RN alone. Given that most patients enrolled in this trial had small renal masses and therefore were at low risk for LN metastases, the question of whether patients with high-risk tumors derive a therapeutic benefit from a standardized, extended LND remains unanswered.

The Effect of Anatomical Location of Lymph Node Metastases on Cancer Specific Survival in Patients with Clear Cell Renal Cell Carcinoma

Background

Positive nodal status (pN1) is an independent predictor of survival in renal cell carcinoma (RCC) patients. However, no study to date has tested whether the location of lymph node (LN) metastases does affect oncologic outcomes in a population submitted to radical nephrectomy (RN) and extended lymph node dissection (eLND).

Objective

To describe nodal disease dissemination in clear cell RCC (ccRCC) patients and to assess the effect of the anatomical sites and the number of nodal areas affected on cancer specific mortality (CSM).

Design, setting and partecipants

The study included 415 patients who underwent RN and eLND, defined as the removal of hilar, side-specific (pre/paraaortic or pre/paracaval) and interaortocaval LNs for ccRCC, at two institutions.

Outcome measurement and statistical analysis

Descriptive statistics were used to depict nodal dissemination in pN1 patients, stratified according to nodal site and number of involved areas. Multivariable Cox regression analyses and Kaplan-Meier curves were used to explore the relationship between pN1 disease features and survival outcomes.

Results and limitations

Median number of removed LN was 14 (IQR 9–19); 23% of patients were pN1. Among patients with one involved nodal site, 54 and 26% of patients were positive only in side-specific and interaortocaval station, respectively. The most frequent nodal site was the interaortocaval and side-specific one, for right and left ccRCC, respectively. Interaortocaval nodal positivity (HR 2.3, CI 95%: 1.3–3.9, p < 0.01) represented an independent predictor of CSM.

Conclusions

When ccRCC patient harbour nodal disease, its spreading can occur at any nodal station without involving the others. The presence of interoartocaval positive nodes does affect oncologic outcomes.

Patient summary

Lymph node invasion in patients with clear cell renal cell carcinoma is not following a fixed anatomical pattern. An extended lymph node dissection, during treatment for primary kidney tumour, would aid patient risk stratification and multimodality upfront treatment.

Lymphatic Drainage from Renal Tumors In Vivo: A Prospective Sentinel Node Study Using SPECT/CT Imaging

PURPOSE

Lymphatic drainage from renal tumors is unpredictable. In vivo drainage studies of primary lymphatic landing sites may reveal the variability and dynamics of lymphatic connections. The purpose of this study was to investigate the lymphatic drainage pattern of renal tumors in vivo with single photon emission/computerized tomography after intratumor radiotracer injection.

MATERIALS AND METHODS

We performed a phase II, prospective, single arm study to investigate the distribution of sentinel nodes from renal tumors on single photon emission/computerized tomography. Patients with cT1-3 (less than 10 cm) cN0M0 renal tumors of any subtype were enrolled in analysis. After intratumor ultrasound guided injection of 0.4 ml ^99mTc-nanocolloid we performed preoperative imaging of sentinel nodes with lymphoscintigraphy and single photon emission/computerized tomography. Sentinel and locoregional nonsentinel nodes were resected with a γ probe combined with a mobile γ camera. The primary study end point was the location of sentinel nodes outside the locoregional retroperitoneal templates on single photon emission/computerized tomography. Using a Simon minimax 2-stage design to detect a 25% extralocoregional retroperitoneal template location of sentinel nodes on imaging at α = 0.05 and 80% power at least 40 patients with sentinel node imaging on single photon emission/computerized tomography were needed.

RESULTS

Of the 68 patients 40 underwent preoperative single photon emission/computerized tomography of sentinel nodes and were included in primary end point analysis. Lymphatic drainage outside the locoregional retroperitoneal templates was observed in 14 patients (35%). Eight patients (20%) had supradiaphragmatic sentinel nodes.

CONCLUSIONS

Sentinel nodes from renal tumors were mainly located in the respective locoregional retroperitoneal templates. Simultaneous sentinel nodes were located outside the suggested lymph node dissection templates, including supradiaphragmatic sentinel nodes in more than a third of the patients.

Beyond penile cancer, is there a role for sentinel node biopsy in urological malignancies?

This review aims to discuss the current state-of-the-art of sentinel node (SN) mapping in urological malignancies. The principles and methodological aspects of lymphatic mapping and SN biopsy in urological malignancies are reviewed. Literature search was restricted to English language. The references of the retrieved articles were examined to identify additional articles. The review also includes meta-analyses published in the past 5 years. SN biopsy for penile cancer is recommended by the European Association of Urology as the preferred staging tool for clinically node-negative patients with at least T1G2 tumours (level of evidence 2a, Grade B). The feasibility of SN biopsy in prostate cancer has been repeatedly demonstrated and its potential value is increasingly being recognised. However, conclusive prospective clinical data as well as consensus on methodology and patient selection are still lacking. For bladder, renal and testicular cancer, only few studies have been published, and concerns around high false-negative rates remain. Throughout the years, the uro-oncological field has portrayed a pivotal role in the development of the SN concept. Recent advances such as hybrid tracers and novel intraoperative detection tools such as fluorescence and portable gamma imaging will hopefully encourage prospectively designed clinical trials which can further substantiate the potential of the SN approach in becoming an integral part of staging in urological malignancies beyond penile cancer.

Detection of micrometastases by flow cytometry in sentinel lymph nodes from patients with renal tumours

BACKGROUND

Stage is an important prognostic factor in renal tumours and dissemination to regional lymph nodes is associated with poor outcomes. Lymph nodes are routinely assessed by immunohistochemistry and microscopic evaluation, a time-consuming process where micrometastases might go undiagnosed. We evaluate an alternative method for detecting metastatic cells in sentinel nodes (SNs) by flow cytometry.

METHODS

A total of 15 nodes from 5 patients diagnosed with renal tumours were analysed by flow cytometry. Staining for the intracellular marker cytokeratin 18 (CK18) with the surface markers carbonic anhydrase IX (CA9) and Cadherin 6 were used in flow cytometry analysis. Peripheral blood mononuclear cells (PBMCs) with the addition of known concentrations of cancer cell lines were analysed to investigate the sensitivity of micrometastasis detection.

RESULTS

Stability of the assay was marked by low intra-assay variability (coefficient of variance ⩽16%) and low inter-assay variability (R²=0.9996-1). Eight nodes in four patients were positive for metastasis; six of them were considered being micrometastatic. These metastases were undetected by routine pathology and the patients were restaged from pN0 to pN1.

CONCLUSIONS

Flow cytometry is able to detect micrometastases in lymph nodes of renal tumour patients that were undetected under H&E examination.

Sentinel lymph node biopsy in renal malignancy: The past, present and future

Sentinel lymph node biopsy (SLNB) is now an established technique in penile and pelvic cancers, resulting in a lower mortality and morbidity when compared with the traditional lymph node dissection. In renal cancer however, despite some early successes for the SLNB technique, paucity of data remains a problem, thus lymph node dissection and extended lymph node dissection remain the management of choice in clinically node positive patients, with surveillance of lymph nodes in those who are clinically node negative. SLNB is a rapidly evolving technique and the introduction of new techniques such as near infra-red fluorescence optical imaging agents and positron emission tomography/computed tomography scans, may improve sensitivity. Evidence in support of this has already been recorded in bladder and prostate cancer. Although the lack of large multi-centre studies and issues around false negativity currently prevent its widespread use, with evolving techniques improving accuracy and the support of large-scale studies, SLNB does have the potential to become an integral part of staging in renal malignancy.

Lymphatic drainage in renal cell carcinoma: back to the basics

Lymphatic drainage in renal cell carcinoma (RCC) is unpredictable, however, basic patterns can be observed in cadaveric and sentinel lymph node mapping studies in patients with RCC. The existence of peripheral lymphovenous communications at the level of the renal vein has been shown in mammals but remains unknown in humans. The sentinel lymph node biopsy technique can be safely applied to map lymphatic drainage patterns in patients with RCC. Further standardisation of sentinel node biopsy techniques is required to improve the clinical significance of mapping studies. Understanding lymphatic drainage in RCC may lead to an evidence-based consensus on the surgical management of retroperitoneal lymph nodes.

Contemporary lymphadenectomy templates: kidney, prostate and bladder cancer

PURPOSE OF REVIEW

Lymph node dissection (LDN) at the time of a primary malignant resection varies in therapeutic and staging outcomes between organs of origin. The purpose of our review is to provide new updates and a key summary on the developments in lymphadenectomy templates in kidney, prostate and bladder cancer.

RECENT FINDINGS

There are still evolving definitions for LDN templates, means of pathologic diagnosis of lymph nodes, as well as implications on staging/cancer-free survival after LND though trends are still emerging.

SUMMARY

Routine lymphadenectomy does not appear to yield benefit in kidney cancer but maybe helpful in those with grossly identifiable disease. For high-risk prostate cancer as well as bladder cancer, extended lymphadenectomy with resection of external and internal iliac and obturator nodes as well as some common iliac nodes can yield survival benefit.