Radiographic size of retroperitoneal lymph nodes predicts pathological nodal involvement for patients with renal cell carcinoma: development of a risk prediction model

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.

Neglected lymph nodal metastases in patients with renal cancer: when to extend the anatomical template of lymph node dissection during nephrectomy

BACKGROUND

The role of lymph node dissection (LND) in patients with renal cell carcinoma (RCC) is still controversial. However, detecting lymph node invasion (LNI) is key due to prognostic implications and to identify patients who might benefit from adjuvant therapies such as adjuvant pembrolizumab.

MATERIALS AND METHODS

Out of 796 patients, 261 (33%) received eLND, of whom 62 (8%) for suspicious lymph node (LN) metastases at preoperative staging (cN1). eLND was divided in 3 anatomical areas: (1) hilar, (2) side-specific (pre-/para-aortic or pre-/para-caval) and (3) inter-aorto-caval nodes. Overall maximum LN diameter was measured by a dedicated radiologist for each patient. Multivariable logistic regression models (MVA) were tested for the effect of maximum LN diameter in predicting the presence of nodal metastases outside the anatomical area of cN1.

RESULTS

LNI was confirmed in 50% of cN1, whilst only 13 out of 199 cN0 patients were pN1 at final histology (6.5%; p < 0.001). In a per-patient analysis, of 62 cN1 patients, 24% vs. 18% vs. 8% harboured pN1 disease only inside vs. in-outside vs. only outside the suspicious anatomical field of cN1 at preoperative CT/MRI scan. At MVA, increasing diameter of suspicious LNs was independently associated with risk of finding positive LNs outside the suspicious anatomical field (OR 1.05, 95%CI 1.02-1.11; p = 0.02).

CONCLUSIONS

Roughly 50% of cN1 patients undergoing eLND will harbour LN metastases, also outside the suspicious radiological area, and maximum LNs diameter at preoperative imaging correlates with such risk. Thus, an eLND might be justified in patients with large suspicious LN metastases, to better stage this patient population and to improve postoperative treatment management.

A Novel Predictive Model of Pathological Lymph Node Metastasis Constructed with Preoperative Independent Predictors in Patients with Renal Cell Carcinoma

Introduction: Renal cell carcinoma (RCC) is one of the most common urinary tumors. The risk of metastasis for patients with RCC is about 1/3, among which 30−40% have lymph node metastasis, and the existence of lymph node metastasis will greatly reduce the survival rate of patients. However, the necessity of lymph node dissection is still controversial at present. Therefore, a new predictive model is urgently needed to judge the risk of lymph node metastasis and guide clinical decision making before operation. Method: We retrospectively collected the data of 189 patients who underwent retroperitoneal lymph node dissection or enlarged lymph node resection due to suspected lymph node metastasis or enlarged lymph nodes found during an operation in Tongji Hospital from January 2016 to October 2021. Univariate and multivariate logistic regression and least absolute shrinkage and selection operator (lasso) regression analyses were used to identify preoperative predictors of pathological lymph node positivity. A nomogram was established to predict the probability of lymph node metastasis in patients with RCC before surgery according to the above independent predictors, and its efficacy was evaluated with a calibration curve and a DCA analysis. Result: Among the 189 patients, 54 (28.60%) were pN1 patients, and 135 (71.40%) were pN0 patients. Three independent impact factors were, finally, identified, which were the following: age (OR = 0.3769, 95% CI = 0.1864−0.7622, p < 0.01), lymph node size according to pre-operative imaging (10−20 mm: OR = 15.0040, 95% CI = 1.5666−143.7000, p < 0.05; >20 mm: OR = 4.4013, 95% CI = 1.4892−7.3134, p < 0.01) and clinical T stage (cT1−2 vs. cT3−4) (OR = 3.1641, 95% CI = 1.0336−9.6860, p < 0.05). The calibration curve and DCA (Decision Curve Analysis) showed the nomogram of this predictive model had good fitting. Conclusions: Low age, large lymph node size in pre-operative imaging and high clinical T stage can be used as independent predictive factors of pathological lymph node metastasis in patients with RCC. Our predictive nomogram using these factors exhibited excellent discrimination and calibration.

A Renewal of the TNM Staging System for Patients with Renal Cancer To Comply with Current Decision-making: Proposal from the European Association of Urology Guidelines Panel

Over the past decade, only minor changes have been introduced in the TNM staging system for renal cancer. Conversely, many milestones and modifications in management of the disease have been achieved, especially for patients with locally advanced and metastatic cancers. The European Association of Urology guidelines panel proposes a new TNM classification scheme for staging of renal cell carcinoma to reflect these breakthrough clinical improvements.

Potential benefit of lymph node dissection during radical nephrectomy for kidney cancer: A review and critical analysis of current literature

Objective

The role of lymph node dissection (LND) is still controversial in patients with renal cell carcinoma undergoing surgery. We aimed to provide a comprehensive review of the literature about the effect of LND on survival, prognosis, surgical outcomes, as well as patient selection and available LND templates.

Methods

Recent literature (from January 2011 to December 2021) was assessed through PubMed and MEDLINE databases. A narrative review of most relevant articles was provided.

Results

The frequencies in which LNDs are being carried out are decreasing due to an increase in minimally invasive and nephron sparing surgery. Moreover, randomized clinical trials and meta-analyses failed to show any survival advantage of LND versus no LND. However, retrospective studies suggest a survival benefit of LND in high-risk patients (bulky tumors, T3-4 stage, and cN1 patients). Moreover, extended LND might provide important staging information, which could be of interest for adjuvant treatment planning.

Conclusion

No level 1 evidence of any survival advantage deriving from LND is currently available in literature. Thus, the role of LND is limited to staging purposes. However, low grade evidence suggests a possible role of LND in high-risk patients. Randomized clinical trials are warranted to corroborate these findings.

Development and validation of a machine learning model to predict the risk of lymph node metastasis in renal carcinoma

SIMPLE SUMMARY

Studies have shown that about 30% of kidney cancer patients will have metastasis, and lymph node metastasis (LNM) may be related to a poor prognosis. Our retrospective study aims to provide a reliable machine learning-based model to predict the occurrence of LNM in kidney cancer. We screened the pathological grade, liver metastasis, M staging, primary site, T staging, and tumor size from the training group (n=39016) formed by the SEER database and the validation group (n=771) formed by the medical center. Independent predictors of LNM in cancer patients. Using six different algorithms to build a prediction model, it is found that the prediction performance of the XGB model in the training group and the validation group is significantly better than any other machine learning model. The results show that prediction tools based on machine learning can accurately predict the probability of LNM in patients with kidney cancer and have satisfactory clinical application prospects.

BACKGROUND

Lymph node metastasis (LNM) is associated with the prognosis of patients with kidney cancer. This study aimed to provide reliable machine learning-based (ML-based) models to predict the probability of LNM in kidney cancer.

METHODS

Data on patients diagnosed with kidney cancer were extracted from the Surveillance, Epidemiology and Outcomes (SEER) database from 2010 to 2017, and variables were filtered by least absolute shrinkage and selection operator (LASSO), univariate and multivariate logistic regression analyses. Statistically significant risk factors were used to build predictive models. We used 10-fold cross-validation in the validation of the model. The area under the receiver operating characteristic curve (AUC) was used to assess the performance of the model. Correlation heat maps were used to investigate the correlation of features using permutation analysis to assess the importance of predictors. Probability density functions (PDFs) and clinical utility curves (CUCs) were used to determine clinical utility thresholds.

RESULTS

The training cohort of this study included 39,016 patients, and the validation cohort included 771 patients. In the two cohorts, 2544 (6.5%) and 66 (8.1%) patients had LNM, respectively. Pathological grade, liver metastasis, M stage, primary site, T stage, and tumor size were independent predictive factors of LNM. In both model validation, the XGB model significantly outperformed any of the machine learning models with an AUC value of 0.916.A web calculator (https://share.streamlit.io/liuwencai4/renal_lnm/main/renal_lnm.py) were built based on the XGB model. Based on the PDF and CUC, we suggested 54.6% as a threshold probability for guiding the diagnosis of LNM, which could distinguish about 89% of LNM patients.

CONCLUSIONS

The predictive tool based on machine learning can precisely indicate the probability of LNM in kidney cancer patients and has a satisfying application prospect in clinical practice.

Oncological outcomes of surgery for isolated retroperitoneal recurrence in renal cancer patients after radical nephrectomy

AIMS

Isolated retroperitoneal recurrence (IRR) in renal cancer patients after radical nephrectomy (RN) is a rare event and poses a therapeutic dilemma. We evaluated oncologic outcomes in surgically treated patients with IRR and established prognostic factors associated with survival. The benefit of metastasis-directed therapy (MDT) in those with clinical progression after extirpation of IRR was assessed.

METHODS

This was a retrospective single-institutional study in which 60 renal cancer patients after previous RN underwent surgery for suspicion of IRR within the period of 2004-2019; in 55 of them, RCC recurrence was histologically confirmed. No patient had distant metastatic disease at the time of IRR diagnosis. In cases of clinical progression after IRR surgery, MDT (metastasectomy, stereotactic radiotherapy) was selectively used. Kaplan-Meier curves were used to estimate survival outcomes. Univariable and multivariable Cox proportional hazards regression analyses were used to evaluate associations between clinicopathological parameters and cancer-specific survival.

RESULTS

Median age at IRR diagnosis was 64 years (range 23-81). IRR was diagnosed at a median of 42 months (IQR 19-99) after RN. Surgical complications of grade 3-5 after IRR extirpation were rare (7%). Median follow-up time was 50 months (IQR 19-80). Five-year recurrence-free survival and cancer-specific survival rates were 32% and 66%, respectively. Radiographic progression was observed in 34 (62%) patients at a median of 11 months after IRR surgery, out of which 22 patients (40%) underwent MDT. When compared with 12 patients without MDT, the MDT patients had a prolonged median time to systemic treatment of 58 (vs. 16 months), and median cancer-specific survival of 88 (vs. 46 months). Upon multivariable analysis, the interval from nephrectomy ≤12 months (HR 7.77), tumour grade 3-4 (HR 13.24) and female sex (HR 7.42) were determined to be independent prognostic factors of cancer-related mortality.

CONCLUSION

Aggressive surgical therapy of IRR is feasible with relatively low morbidity. More than half of the patients experience long-term survival. The interval from nephrectomy to IRR less than 12 months, tumour grade 3-4 and female sex were negative prognostic predictors. In the case of progression, metastasis-directed therapy may prolong the interval to initiation of systemic treatment.

Choice of Surgical Options in Kidney Cancer and Surgical Complications

Surgical resection of renal cell carcinoma plays a large role in the overall management of the disease. The gold standard for surgical management historically has been open or laparoscopic radical nephrectomy, however, evidence of equivalent oncologic efficacy with improved clinical outcomes has driven the use of nephron-sparing surgeries, especially for smaller and localized renal tumors. A role for surgery remains in metastatic RCC as well, but controversy exists as to which patients may benefit most from surgical intervention in addition to other systemic targeted therapies. This article focuses specifically on renal cell carcinoma, transitional cell carcinoma is not described here.

Prognostic Value of Positive Lymph Nodes in Patients with Renal Cell Carcinoma and Tumor Thrombus Undergoing Nephrectomy and Thrombectomy

INTRODUCTIONS

The objective of this study was to determine the prognostic value of positive lymph nodes (LNs) in patients with renal cell carcinoma (RCC) and tumor thrombus (TT) and to explore risk factors predicting LNs metastasis.

METHODS

We retrospectively analyzed 216 patients with RCC and TT treated at a single institution from January 2015 to December 2019. Overall survival (OS) and progression-free survival (PFS) was estimated using the Kaplan-Meier curves divided by pathological LN status. Associations between clinicopathological features and survival outcomes were evaluated using Cox regression models. Logistic regression model was performed to determine risk factors associated with LN metastasis.

RESULTS

We identified 216 patients with RCC and TT including 85 (39.4%) who did and 131 (60.6%) who did not undergo lymph node dissection. Pathologically positive LNs were found in 18 (8.3%) cases. pN1 had significant worse OS (median: 21 vs. 41 and 56 months, p < 0.001) and PFS (median:14 vs. 29 and 33 months, p < 0.001) than pN0 and pNx respectively. However, survival outcomes of OS and PFS were similar between pNx-0/M1 and pN1/M0 group and between 1- and ≥2-node-positive group. Non-CCRCC (p = 0.001), sarcomatoid differentiation (p < 0.001), and pathologically positive LNs (p = 0.025) were independent prognostic predictors predicting worse OS while distance metastasis (p = 0.009), non-CCRCC (p = 0.023), necrosis (p = 0.014), sarcomatoid differentiation (p = 0.003), and pathologically positive LNs (p = 0.007) were independent prognostic indicators predicting worse PFS. Clinically positive LNs (p = 0.014) and sarcomatoid differentiation (p = 0.009) were predictors of positive LNs.

CONCLUSIONS

LNs metastasis independently associated with worse survival outcomes in RCC and TT populations, with similar survival outcomes compared to distance metastasis. Therefore, more accurate risk stratification is warranted for guiding postoperative surveillance and adjuvant therapy.

Lymph node dissection during radical nephrectomy: A Canadian multi-institutional analysis

OBJECTIVES

To determine the association between lymph node dissection (LND) at the time of radical nephrectomy and survival in a large, multi-institutional cohort using a propensity score matching design.

SUBJECTS AND METHODS

The Canadian Kidney Cancer information system was used to identify patients undergoing radical nephrectomy for nonmetastatic renal cell carcinoma. Associations between LND with overall survival , recurrence free survival and cancer specific survival were determined using various propensity score techniques in the overall cohort and in patients with varying probabilities of pN1. Cox models were used to determine association of lymph node removed with outcomes.

RESULTS

Of the 2,699 eligible patients, 812 (30%) underwent LND. Of the LND patients, 88 (10.8%) had nodal metastases. There was no association between LND and improved overall survival, recurrence free survival or cancer specific survival using various propensity score techniques (stratification by propensity score quintile, matched pairs, inverse treatment probability weighting and adjusted for propensity score quintile). There was no association between LND and a therapeutic benefit in patients with increased threshold probabilities of nodal metastases. Increased number of lymph nodes removed was not associated with improved survival outcomes.

CONCLUSIONS

LND at the time of radical nephrectomy for renal cell carcinoma is not associated with improved outcomes. There was no benefit in patients at high risk for nodal metastases, and the number of nodes removed did not correlate with survival. Further studies are needed to determine which high risk patients may benefit from LND.

MRI radiomics-based nomogram for individualised prediction of synchronous distant metastasis in patients with clear cell renal cell carcinoma

OBJECTIVE

To evaluate the performance of a multiparametric MRI radiomics-based nomogram for the individualised prediction of synchronous distant metastasis (SDM) in patients with clear cell renal cell carcinoma (ccRCC).

METHODS

Two-hundred and one patients (training cohort: n = 126; internal validation cohort: n = 39; external validation cohort: n = 36) with ccRCC were retrospectively enrolled between January 2013 and June 2019. In the training cohort, the optimal MRI radiomics features were selected and combined to calculate the radiomics score (Rad-score). Incorporating Rad-score and SDM-related clinicoradiologic characteristics, the radiomics-based nomogram was established by multivariable logistic regression analysis, then the performance of the nomogram (discrimination and clinical usefulness) was evaluated and validated subsequently. Moreover, the prediction efficacy for SDM in ccRCC subgroups of different sizes was also assessed.

RESULTS

Incorporating Rad-score derived from 9 optimal MR radiomics features (age, pseudocapsule and regional lymph node), the radiomics-based nomogram was capable of predicting SDM in the training cohort (area under the ROC curve (AUC) = 0.914) and validated in both the internal and external cohorts (AUC = 0.854 and 0.816, respectively) and also showed a convincing predictive power in ccRCC subgroups of different sizes (≤ 4 cm, AUC = 0.875; 4-7 cm, AUC = 0.891; 7-10 cm, 0.908; > 10 cm, AUC = 0.881). Decision curve analysis indicated that the radiomics-based nomogram is of clinical usefulness.

CONCLUSIONS

The multiparametric MRI radiomics-based nomogram could achieve precise individualised prediction of SDM in patients with ccRCC, potentially improving the management of ccRCC.

KEY POINTS

• Radiomics features derived from multiparametric magnetic resonance images showed relevant association with synchronous distant metastasis in clear cell renal cell carcinoma. • MRI radiomics-based nomogram may serve as a potential tool for the risk prediction of synchronous distant metastasis in clear cell renal cell carcinoma.

The Role of Lymphadenectomy in Patients with Advanced Renal Cell Carcinoma

The role of lymph node dissection (LND) in the management of renal cell carcinoma (RCC) is controversial. LND serves an indisputable staging role by providing pathologic nodal stage. However, while earlier observational studies had suggested a survival benefit to LND, more recent observational evidence and a randomized trial do not support a survival benefit. The majority of patients with isolated lymph node involvement appear to harbor occult metastatic disease. Still, LND is not associated with increased perioperative morbidity when performed in experienced centers. LND may therefore play a predominantly staging role in patients at increased risk of lymph node metastases.

Retroperitoneal and Pelvic Lymph Nodes in Children: What Is Normal?

OBJECTIVE. The purpose of this study was to evaluate size criteria for retroperitoneal and pelvic lymph nodes in healthy children. MATERIALS AND METHODS. We identified all trauma patients younger than 18 years old without underlying disease and with CT scans without abnormalities in the abdomen and pelvis during 2014-2015. Two pediatric radiologists reviewed the studies independently and recorded the number of retroperitoneal and pelvic lymph nodes with a long diameter 5 mm or greater and the size (two perpendicular diameters) of the largest lymph node in five anatomic locations. Discrepant results were reviewed in consensus. The relationship of short diameter to age and interobserver variability was evaluated. RESULTS. A total of 166 patients (86 boys) with a mean age of 7.2 years old (range, 0.1-18.0 years old) were identified. More than 95% of lymph nodes in the retroperitoneum and pelvis had a short diameter measuring at most 7 and 8 mm, respectively, by consensus. The size of the largest short diameter of lymph nodes did not vary with age. More than four lymph nodes were identified in any anatomic location in only three patients, by only one of the radiologists. Agreement for lymph nodes with largest diameter of 5 mm or greater between radiologists ranged from 70.5% to 97.6% for the five anatomic locations with poor interobserver agreement (κ, 0.2-0.3). CONCLUSION. The size and number of retroperitoneal and pelvic lymph nodes in children are less than in adults. A short diameter threshold of 7 mm (retroperitoneal) and 8 mm (pelvic) and more than four lymph nodes with long diameter of 5 mm or greater in one location may define disease.

Chest computed tomography for staging renal tumours: validation and simplification of a risk prediction model from a large contemporary retrospective cohort

OBJECTIVES

To externally validate a nomogram recently proposed by Larcher et al. (BJU Int. 2017; 120: 490) and to develop a simplified model with comparable accuracy to guide on the need for staging chest computed tomography (CT) for patients with new renal masses.

PATIENTS AND METHODS

We analysed the data of 1082 consecutive patients with unilateral enhancing renal masses referred to urology multidisciplinary team meetings at two centres between 2011 and 2017. All patients underwent a staging chest CT at diagnosis. We fitted multivariable logistic regression models and tested the Larcher model performance using area under the receiver-operating curve (AUC), calibration and decision curve analysis.

RESULTS

Forty-two patients (3.9%) had a positive chest CT. The Larcher nomogram had an AUC of 83.8% (95% confidence interval [CI] 77.1-90.6), but was only moderately well calibrated (calibration-in-the-large = -0.61, slope = 0.82). Specifically, the nomogram overestimated the risk of positive chest CT, and the magnitude of miscalibration increased with increasing predicted risks. Using a stepwise backward approach, a new model was developed including tumour size, nodal stage and systemic symptoms. Compared with the Larcher model, the new model had a similar AUC (82.7% [95% CI 75.5-90.0]), but improved calibration and clinical net benefit. The predicted risk of positive chest CT was <1% in the low-risk group and 1.9-79.9% in the high-risk group.

CONCLUSION

The Larcher nomogram is an accurate prediction tool that was moderately well calibrated with our dataset. However, our simplified model has similar accuracy and uses more objective variables available from referral, so may be easier to incorporate into clinical practice. The low-risk group from our model (tumour size ≤4 cm and no systemic symptoms) had a risk of positive chest CT <1%, suggesting these patients may forego chest CT.

Accuracy of clinical nodal staging and factors associated with receipt of lymph node dissection at the time of surgery for nonmetastatic renal cell carcinoma

INTRODUCTION

The benefit of lymph node dissection (LND) in renal cell carcinoma (RCC) remains poorly defined. Despite this uncertainty, the American Urological Association (AUA) guideline on localized renal cancer recommends that LND be performed for staging purposes when there is suspicion of regional lymphadenopathy on imaging. Using the National Cancer Database (NCDB), we sought to determine how much of a departure the new AUA guideline is from current practice. We hypothesized that practice patterns would reflect the "Expert Opinion" recommendation and that patients who are clinical lymph node (cLN) positive would receive a LND more often than those who are cLN negative. Additionally, we sought to determine factors that would trigger a LND as well the accuracy of clinical staging by examining the relationship between cLN and pathologic lymph node (pLN) status of patients who received a LND.

MATERIALS AND METHODS

The NCDB was queried for patients with nonmetastatic RCC who underwent partial nephrectomy or nephrectomy from 2010 to 2014. Patient sociodemographic and clinical characteristics were extracted. Frequency distributions were calculated for patients with both cLN and pLN status available. Of patients who received a LND, sensitivity, specificity, and positive/negative predictive values (PPV/NPV) of cLN status for pLN positivity were calculated. Logistic regression models were used to examine association between clinical and socioeconomic factors and receipt of LND. Propensity score matching was used in sensitivity analyses to examine potential for reporting bias in NCDB data.

RESULTS

We identified 110,963 patients who underwent surgery for RCC, of whom 11,867 (11%) had LND performed at the time of surgery. cLN and pLN information were available in 11,300 patients, of which 1,725 were preoperatively staged as having positive cLN. More LNDs were performed per year for patients who were cLN negative than cLN positive. Of patients who received a LND, the majority of patients were cLN negative across all clinical T (cT) stages. Multivariable analysis showed that all patients who had care at an academic/research institution (odds ratio [OR]: 1.58, 95% confidence interval [CI]: 1.43-1.74) and had to travel >12.5 to 31.0 miles and >31.0 miles to a treatment center (OR: 1.08, 95%CI: 1.01-1.15 and OR: 1.28, 95%CI: 1.20-1.36, respectively) were more likely to get a LND. As cT stage increased from cT2-4, the risk of LND increased (OR range: 4.7-7.90, respectively). Patients who were cLN positive were more likely to receive a LND at the time of surgery (OR: 18.68, 95%CI: 16.62-21.00). Of the patients who received a LND, clinical staging was more specific than sensitive.

CONCLUSION

More patients received a LND who were cLN negative compared to patients who were cLN positive. Patients who were cLN positive were more likely to receive a LND. Treatment center type, distance to treatment center, cT stage, and cLN positivity were factors associated with LND receipt.

Renal cell carcinoma staging: pitfalls, challenges, and updates

Renal cell carcinoma (RCC) is unusual among cancers in that it often grows as a spherical, well-circumscribed mass. Increasing tumour size influences the pathological pT stage category within pT1 and pT2, with cutoffs of 40, 70 and 100 mm; however, with increasing size also comes a sharp increase in the likelihood of renal sinus or renal vein tributary invasion, such that clear cell RCC rarely reaches 70 mm without invading one of these. To clarify some previous challenges in assigning tumour stage, the American Joint Committee on Cancer 2016 tumor-node-metastasis classification has removed the requirements than vein invasion be recognised grossly and that vein walls contain muscle for the diagnosis of vein invasion. Renal pelvis invasion has also been added as an additional route to pT3a. Multinodularity or finger-like extensions from a renal mass should be viewed with great suspicion for the possibility of vein or renal sinus invasion, and, as tumour size increases to over 40-50 mm, thorough sampling of the renal sinus interface should always be undertaken. With increasing interest in adjuvant therapy in renal cancer, the pathologist's role in RCC staging will continue to be an important prognostic parameter and a tool for selection of patients for enrolment in clinical trials.

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.

Predictive and prognostic effect of inflammatory lymphadenopathies in renal cell carcinoma

PURPOSE

A significant proportion of patients affected by renal cell carcinoma (RCC) shows a suspicious lymph node involvement (LNI) at preoperative imaging. We sought to evaluate the effect of lymphadenopathies (cN1) on survival in surgical RCC patients with no evidence of LNI at final pathology (pN0).

METHODS

719 patients underwent either radical or partial nephrectomy and lymph node dissection at a single tertiary care referral centre between 1987 and 2015. All patients had pathologically no LNI (pN0). Outcomes of the study were cancer-specific mortality (CSM) and other-cause mortality. Multivariable competing-risks regression models assessed the impact of inflammatory lymphadenopathies (cN1pN0) on mortality rates, after adjustment for clinical and pathological confounders.

RESULTS

114 (16%) and 605 (84%) patients (16%) were cN1pN0 and cN0pN0, respectively. cN1pN0 patients were more frequently diagnosed with larger tumours (8.4 vs. 6.5 cm), higher pathological tumour stage (pT3-4 in 71 vs. 36%), higher Fuhrman grade (G3-G4 in 64 vs. 31%), more frequently with necrosis (75 vs. 44%), and distant metastases (33 vs. 10%) (all p < 0.0001). At univariable analysis, inflammatory lymphadenopathies resulted associated with worse CSM (HR 2.45; p < 0.0001). However, at multivariable analysis, inflammatory lymphadenopathies were not an independent predictor of CSM (HR 0.81; p = 0.4). The presence of metastases at diagnosis was the most important factor affecting CSM (HR 6.54; p < 0.0001). This study is limited by its retrospective nature.

CONCLUSIONS

In RCC patients, inflammatory lymphadenopathies (cN1pN0) are associated with unfavourable clinical and pathological characteristics. However, the presence of inflammatory lymphadenopathies does not affect RCC-specific mortality.

The role of lymph node dissection in the management of renal cell carcinoma: a systematic review and meta-analysis

Our objective was to evaluate the role of retroperitoneal lymph node dissection (LND) in non-metastatic (M0) and metastatic (M1) renal cell carcinoma (RCC). We searched Medline, EMBASE, Web of Science and Scopus from database inception to 29 August 2017 for studies of patients who underwent partial or radical nephrectomy for M0 or M1 RCC. Two investigators independently selected studies for inclusion. Risk of bias was assessed using the Newcastle-Ottawa scale, Cochrane Collaboration tool and National Heart, Lung and Blood Institute Quality Assessment Tool. Random effects meta-analysis was performed for all-cause-mortality. The GRADE approach was used to characterize quality of evidence. A total of 51 unique studies were included in the qualitative systematic review. Risk of bias was low in 41/51 (80%) studies. LND was not associated with all-cause mortality in either M0 (hazard ratio [HR] 1.02, 95% confidence interval [CI] 0.92-1.12; I² = 0%; four studies), M1 (HR 1.04, 95% CI 0.83-1.29; I² = 0%; two studies), or pooled M0 and M1 settings (HR 1.00, 95% CI 0.92-1.09; I² = 0%; seven studies), with no statistically significant differences according to M stage subgroups (P = 0.50). In the three studies that examined M0 subgroups with a high risk of nodal metastasis, LND was not associated with improved oncological outcomes. Studies on the association of extent of LND with survival reported inconsistent results. Meanwhile, a small proportion of patients with pN1M0 disease demonstrate durable long-term oncological control after surgery, with 10-year cancer-specific survival of 21-31%. Nodal involvement is independently associated with adverse prognosis in both M0 and M1 settings. GRADE quality of evidence was moderate or low for the outcomes examined. Although LND yields independent prognostic information, the existing literature does not support a therapeutic benefit to LND in either M0 or M1 RCC. High-risk M0 patient groups warrant further study, as a subset of patients with isolated nodal metastases experience long-term survival after surgical resection.

The efficacy and safety of microwave ablation in patients with retroperitoneal metastases

BACKGROUND

Retroperitoneal metastases are common, and most present with symptoms; however, treatments for this condition are limited. This retrospective study verified the efficacy and safety of microwave ablation (MWA) in retroperitoneal metastases patients.

METHODS

Patients with pathologically confirmed malignant carcinoma and imaging showing retroperitoneal metastases were enrolled and underwent MWA. The end-points included objective response rate, time to local progression (TTLP), overall survival, visual analogue scale (VAS) score, dose of morphine pre- and post-ablation and complications.

RESULTS

Twenty-three patients were enrolled. The mean tumour diameter was 3.6 cm. Altogether, 29 tumour sites in 23 patients were ablated during 23 procedures; technical success was achieved in all 23 patients. The objective response and disease control rates were 95.7% and 100.0%, respectively. The mean TTLP and median OS were 22.8 months (95% CI: 16.1-29.6 months) and 10.6 months (95% CI: 7.4-13.8 months), respectively. In 13 patients with symptoms, the VAS values before ablation and 48 h, 1 month, 2 months, 3 months and 6 months after ablation were 5.38, 2.77 (p = 0.015), 2.15 (p = 0.001), 2.17 (p = 0.001), 1.40 (p = 0.000) and 1.71 (p = 0.006), respectively. The corresponding morphine doses were 76.9 mg, 70.7 mg (p = 0.584), 50.7 mg (p = 0.031), 55.0 mg (p = 0.097), 46.0 mg (p = 0.057) and 40.0 mg (p = 0.363), respectively. No ablation-associated mortality was observed. Major complications, minor complications and adverse events were observed in eight (34.8%), five (21.7%) and four (17.4%) patients, respectively.

CONCLUSION

MWA for the treatment of retroperitoneal metastases was effective and the complications were common.

Surgical Management of Advanced and Metastatic Renal Cell Carcinoma: A Multidisciplinary Approach

The past decade has seen a rapid proliferation in the number and types of systemic therapies available for renal cell carcinoma. However, surgery remains an integral component of the therapeutic armamentarium for advanced and metastatic kidney cancer. Cytoreductive surgery followed by adjuvant cytokine-based immunotherapy (predominantly high-dose interleukin 2) has largely given way to systemic-targeted therapies. Metastasectomy also has a role in carefully selected patients. Additionally, neoadjuvant systemic therapy may increase the feasibility of resecting the primary tumor, which may be beneficial for patients with locally advanced or metastatic disease. Several prospective trials examining the role of adjuvant therapy are underway. Lastly, the first immune checkpoint inhibitor was approved for metastatic renal cell carcinoma (mRCC) in 2015, providing a new treatment mechanism and new opportunities for combining systemic therapy with surgery. This review discusses current and historical literature regarding the surgical management of patients with advanced and mRCC and explores approaches for optimizing patient selection.

Lymph Node Dissection for Small Renal Masses

Because the majority of small renal masses (SRMs; <4 cm) demonstrate low metastatic potential and can be effectively treated with radical or partial nephrectomy, the role of lymph node dissection (LND) at the time of surgery is unclear. A randomized trial demonstrated no survival benefit of LND in clinically localized renal cell carcinoma. Thus, LND is not recommended routinely for SRMs. For patients with high-risk features or radiographic evidence of lymphadenopathy, however, LND may improve local staging and potentially provide a survival benefit. If performed, a LND template should be based on the known lymphatic drainage of the kidneys.

Renal Cell Carcinoma with Isolated Lymph Node Involvement: Long-term Natural History and Predictors of Oncologic Outcomes Following Surgical Resection

BACKGROUND

Renal cell carcinoma (RCC) with isolated lymph node (LN) involvement has historically been associated with poor prognosis. However, a subset of patients may experience long-term survival.

OBJECTIVE

To examine the natural history of RCC with isolated LN involvement following surgical resection with long-term follow-up, and to evaluate clinicopathologic features associated with disease progression and survival.

DESIGN, SETTING, AND PARTICIPANTS

A total of 138 patients with isolated pN1M0 RCC underwent partial or radical nephrectomy and LN dissection from 1980 to 2010.

INTERVENTION

Partial or radical nephrectomy with LN dissection.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Metastasis-free survival (MFS), cancer-specific survival (CSS), and overall survival (OS) were estimated using the Kaplan-Meier method. Associations between clinicopathologic features and oncologic outcomes were evaluated using Cox regression models.

RESULTS AND LIMITATIONS

Median follow-up among survivors was 8.5 yr. The 5-yr and 10-yr MFS, CSS, and OS rates were 16% and 15%, 26% and 21%, and 25% and 15%, respectively. The median time to development of metastases was only 4.2 mo. On multivariable analysis, symptoms at presentation (hazard ratio [HR] 2.40; p=0.03), inferior vena cava tumor thrombus (HR 1.99; p=0.003), clear cell (HR 2.21; p=0.01) and collecting duct/not otherwise specified (HR 4.28; p<0.001) histologic subtypes, pT4 stage (HR 2.64; p=0.005), and coagulative tumor necrosis (HR 2.51; p<0.001) were independently associated with development of metastases. MFS rates at 1 yr after surgery were 71%, 63%, 33%, and 7% for patients with one, two, three, and four to five adverse features, respectively. Limitations include surgical selection bias.

CONCLUSIONS

Although isolated pN1 disease portends a poor prognosis, a small subset of patients experience durable long-term survival after surgical resection of isolated lymphatic metastases. Adverse prognostic features may enhance patient risk stratification and facilitate multimodal management approaches.

PATIENT SUMMARY

Although isolated lymph node metastases portend a poor prognosis, a small subset of patients experience long-term survival following surgical resection.