Renal cell carcinoma and pathologic nodal disease: Implications for American Joint Committee on Cancer staging

Should Patients with Renal Cell Carcinoma and Pathological Nodal Invasion Be Classified As Having Stage IV Disease?

BACKGROUND

Lymph node invasion is associated with poor outcome in patients with renal cell carcinoma (RCC).

PATIENTS AND METHODS

Patients with RCC within a single center from 2001 to 2018 were retrospectively obtained from the Chang Gung Research Database. Patient gender, physical status, Charlson Comorbidity Index, tumor side, histology, age at diagnosis, and body mass index (BMI) were compared. The overall survival (OS) and cancer-specific survival (CSS) of each group were estimated using the Kaplan-Meier method. Log-rank tests were used to compare between the subgroups.

RESULTS AND CONCLUSIONS

A total of 335 patients were enrolled, of whom 76 had pT3N0M0, 29 had pT1-3N1M0, 104 had T1-4N0M1, and 126 had T1-4N1M1 disease. Significant OS difference was noted between pT3N0M0 and pT1-3N1M0 groups with 12.08 years [95% confidence interval (CI), 8.33-15.84] versus 2.58 years (95% CI, 1.32-3.85), respectively (P < 0.005). No significant difference was observed in OS between pT1-3N1M0 and T1-4N0M1 groups with 2.58 years (95% CI, 1.32-3.85) versus 2.50 years (95% CI, 1.85-3.15, P = 0.72). The OS of N1M1 group was worse than that of N0M1 group with 1.00 year (95% CI, 0.74-1.26) versus 2.50 years (95% CI, 1.85-3.15, P < 0.05). Similar results were also observed in CSS. In summary, we claim that RCC with lymph node (LN) invasion should be reclassified as stage IV disease in terms of survival outcome.

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.

Integrating Surgery in the Multidisciplinary Care of Advanced Renal Cell Carcinoma

The role of surgery for patients with locally advanced and metastatic renal cell carcinoma (RCC) is not precisely defined in our contemporary era of systemic therapies. Research in this field is focused on the role of regional lymphadenectomy, along with indications and timing of cytoreductive nephrectomy and metastasectomy. As our understanding of the molecular and immunological basis of RCC continues to develop along with the advent of novel systemic therapies, prospective clinical trials will be critical in defining how surgery should be integrated into the treatment paradigm of advanced RCC.

Using machine learning to predict lymph node metastasis in patients with renal cell carcinoma: A population-based study

Background

Lymph node (LN) metastasis is strongly associated with distant metastasis of renal cell carcinoma (RCC) and indicates an adverse prognosis. Accurate LN-status prediction is essential for individualized treatment of patients with RCC and to help physicians make appropriate surgical decisions. Thus, a prediction model to assess the hazard index of LN metastasis in patients with RCC is needed.

Methods

Partial data were extracted from the Surveillance, Epidemiology, and End Results (SEER) database. Data of 492 individuals with RCC, collected from the Southwest Hospital in Chongqing, China, were used for external validation. Eight indicators of risk of LN metastasis were screened out. Six machine learning (ML) classifiers were established and tuned, focused on predicting LN metastasis in patients with RCC. The models were integrated with big data analytics and ML algorithms. Based on the optimal model, we developed an online risk calculator and plotted overall survival using Kaplan-Meier analysis.

Results

The extreme gradient-boosting (XGB) model was superior to the other models in both internal and external trials. The area under the curve, accuracy, sensitivity, and specificity were 0.930, 0.857, 0.856, and 0.873, respectively, in the internal test and 0.958, 0.935, 0.769, and 0.944, respectively, in the external test. These parameters show that XGB has an excellent ability for clinical application. The survival analysis showed that patients with predicted N1 tumors had significantly shorter survival (p < 0.0001).

Conclusion

Our study shows that integrating ML algorithms and clinical data can effectively predict LN metastasis in patients with confirmed RCC. Subsequently, a freely available online calculator (https://xinglinyi.shinyapps.io/20221004-app/) was built, based on the XGB model.

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.

Development and validation of a prognostic nomogram for predicting cancer-specific survival in patients with metastatic clear cell renal carcinoma: A study based on SEER database

Objectives

Clear cell renal cell carcinoma (ccRCC) is highly prevalent, prone to metastasis, and has a poor prognosis after metastasis. Therefore, this study aimed to develop a prognostic model to predict the individualized prognosis of patients with metastatic clear cell renal cell carcinoma (mccRCC).

Patients and Methods

Data of 1790 patients with mccRCC, registered from 2010 to 2015, were extracted from the Surveillance, Epidemiology and End Results (SEER) database. The included patients were randomly divided into a training set (n = 1253) and a validation set (n = 537) based on the ratio of 7:3. The univariate and multivariate Cox regression analyses were used to identify the important independent prognostic factors. A nomogram was then constructed to predict cancer specific survival (CSS). The performance of the nomogram was internally validated by using the concordance index (C-index), calibration plots, receiver operating characteristic curves, net reclassification improvement (NRI), integrated discrimination improvement (IDI), and decision curve analysis (DCA). We compared the nomogram with the TNM staging system. Kaplan–Meier survival analysis was applied to validate the application of the risk stratification system.

Results

Diagnostic age, T-stage, N-stage, bone metastases, brain metastases, liver metastases, lung metastases, chemotherapy, radiotherapy, surgery, and histological grade were identified as independent predictors of CSS. The C-index of training and validation sets are 0.707 and 0.650 respectively. In the training set, the AUC of CSS predicted by nomogram in patients with mccRCC at 1-, 3- and 5-years were 0.770, 0.758, and 0.757, respectively. And that in the validation set were 0.717, 0.700, and 0.700 respectively. Calibration plots also showed great prediction accuracy. Compared with the TNM staging system, NRI and IDI results showed that the predictive ability of the nomogram was greatly improved, and DCA showed that patients obtained clinical benefits. The risk stratification system can significantly distinguish the patients with different survival risks.

Conclusion

In this study, we developed and validated a nomogram to predict the CSS rate in patients with mccRCC. It showed consistent reliability and clinical applicability. Nomogram may assist clinicians in evaluating the risk factors of patients and formulating an optimal individualized treatment strategy.

A 25 year perspective on the evolution and advances in an understanding of the biology, evaluation and treatment of kidney cancer

The diagnosis, evaluation and management of patients with renal cell carcinoma has transformed in the 21st century. Utilizing biological discoveries and technological advances, the field has moved from blunt surgical and largely ineffective medical treatments, to nuanced and fine-tuned approaches based on biology, extent of disease and patient preferences. In this review we will summarize the last 25 years of progress in kidney cancer.

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.

Expression levels of VEGF-C and VEGFR-3 in renal cell carcinoma and their association with lymph node metastasis

Renal cell carcinoma (RCC) is the most common form of kidney cancer. Vascular endothelial growth factor-C (VEGF-C) and its receptor, VEGFR-3, are involved in lymphangiogenesis. The aim of the present study was to investigate the expression levels of VEGF-C and VEGFR-3 in RCC, and their association with lymphatic vessel density (LVD) and lymph node metastasis. The mRNA expression levels of VEGF-C in 40 RCC tissues and 10 normal renal tissues were determined by reverse transcription-semiquantitative PCR. The differential expression of VEGF-C and VEGFR-3 was examined by immunohistochemistry. Using an anti-D2-40 antibody as a lymphatic marker, the morphology and structure of lymphatic vessels in tissues was examined, and the LVD was calculated. VEGF-C mRNA expression in RCC tissues was higher than that in normal renal tissues, and VEGF-C mRNA expression in the lymph node metastasis group was higher than that in the non-lymph node metastasis group. The positive expression rate of VEGF-C and VEGFR-3 in RCC tissues was significantly higher than that in normal renal tissues. VEGF-C expression in the lymph node metastasis group was significantly higher than that in the non-lymph node metastasis group, and the positive expression of VEGF-C was associated with the clinical staging of RCC. In addition, there was a correlation between VEGF-C and VEGFR-3 expression in tumor cells. The LVD around the tumor was higher than that in the center of the tumor tissues and normal renal tissues, and it was closely associated with lymphatic invasion and lymph node metastasis. Overall, the current findings demonstrated that the VEGF-C/VEGFR-3 signaling pathway promoted lymphangiogenesis around the tumor and provided an approach for tumor lymphatic invasion and lymph node metastasis. Therefore, VEGFC and VEGFR-3 expression may serve an important role in the initiation and development of RCC.

Outcome after resection of occult and non-occult lymph node metastases at the time of nephrectomy

PURPOSE

There is sparse evidence on outcomes of resected occult LN metastases at the time of nephrectomy (synchronous disease). We sought to analyse a large international cohort of patients and to identify clinico-pathological predictors of long-term survival.

MATERIALS AND METHODS

We collected data of consecutive patients who underwent nephrectomy and LND for T_any cN0-1pN1 and cM0-1 RCC at 7 referral centres between 1988 and 2019. Patients were stratified into four clinico-pathological groups: (1) cN0cM0-pN1, (2) cN1cM0-pN1(limited, 1-3 positive nodes), (3) cN1cM0-pN1(extensive, > 3 positive nodes), and (4) cM1-pN1. Overall survival (OS) was estimated using the Kaplan-Meier method, and associations with all-cause mortality (ACM) were evaluated using Cox models with multiple imputations.

RESULTS

Of the 4370 patients with LND, 292 patients with pN1 disease were analysed. Median follow-up was 62 months, during which 171 patients died. Median OS was 21 months (95% CI 17-30 months) and the 5-year OS rate was 24% (95% CI 18-31%). Patients with cN0cM0-pN1 disease had a median OS of 57 months and a 5-year OS rate of 43%. 5-year OS (median OS) decreased to 29% (33 months) in cN1cM0-pN1(limited) and to 23% (23 months) in cN1cM0-pN1(extensive) patients. Those with cM1-pN1 disease had the worst prognosis, with a 5-year OS rate of 13% (9 months). On multivariable analysis, age (p = 0.034), tumour size (p = 0.02), grade (p = 0.02) and clinico-pathological group (p < 0.05) were significant predictors of ACM.

CONCLUSION

Depending on clinico-pathological group, grade and tumour size, 5-year survival of patients with LN metastases varies from 13 to 43%. Patients with resected occult lymph node involvement (cN0/pN1 cM0) have the best prognosis with a considerable chance of long-term survival.

Organotypic primary blood vessel models of clear cell renal cell carcinoma for single-patient clinical trials

Clear cell renal cell carcinoma (ccRCC) is a common genitourinary cancer associated with the development of abnormal tumor angiogenesis. Although multiple anti-angiogenic therapies have been developed, responses to individual treatment are highly variable between patients. Thus, the use of one-patient clinical trials has been suggested as an alternative to standard trials. We used a microfluidic device to generate organotypic primary patient-specific blood vessel models using normal (NEnC) and tumor-associated primary CD31+ selected cells (TEnC). Our model was able to recapitulate differences in angiogenic sprouting and vessel permeability that characterize normal and tumor-associated vessels. We analyzed the expression profile of vessel models to define vascular normalization in a patient-specific manner. Using this data, we identified actionable targets to normalize TEnC vessel function to a more NEnC-like phenotype. Finally, we tested two of these drugs in our patient-specific models to determine the efficiency in restoring vessel function showing the potential of the model for single-patient clinical trials.

Lymph node yield in pediatric, adolescent and young adult Renal Cell Carcinoma - How many are enough?

PURPOSE

Pediatric, adolescent and young adult (PAYA) patients with renal cell carcinoma (RCC) have a high rate of LN involvement, yet data to guide surgical lymph node (LN) management in this group is limited. The objective is to describe a LN yield threshold to quantify the chance of missing occult LN involvement at ≤10% in PAYAs with RCC.

MATERIALS & METHODS

The National Cancer Database was queried for patients aged ≤30 y with unilateral, non-metastaticRCC from 2004 to 2013. The probability of a false negative LN sampling was determined on the cohort of patients who had at least one positive LNand ≥ 2 LNs examined. For a given LN yield, the probability that a positive LN exists but none were found was estimated using a beta-binomial model.

RESULTS

We identified 112 patients meeting study criteria. Median age was 24 y and median tumor size was 9.5 cm (IQR 5.8-14). The median number of LNs sampled was 7 (IQR 4-12) and the median number of LNs positive was 4 (IQR 2-7). To achieve ≤10% probability of a false-negativeLN sampling, the beta-binomial model estimated that 5 LNs (95% CI4-7) must be sampled.

CONCLUSIONS

The desired LN yield to reduce the risk of a false-negativeLN sampling in PAYAs with RCC to ≤10% is 5. This is in keeping with prior studies identifying a LN yield of 6-10 to achieve the same. These data may be used to standardize surgical guidelines when treating PAYAs with renal tumors.

LEVEL OF EVIDENCE

II.

Is lymph node dissection necessary for staging while undergoing nephrectomy in patients with renal cell carcinoma?

OBJECTIVE

The essential treatment for patients with renal cell carcinoma is nephrectomy. As no lymph node dissection (LND) could be performed in the majority of these patients, healthy staging could not be carried out. In this study, we investigated the impact of LND during nephrectomy on patient survival.

METHODS

A total of 181 patients-58 (32%) were female and 123 (68%) were male-were included in the study. Median follow-up period was 48 months. The patients were separated into 4 groups according to their stage during diagnosis; group 1 (T1-3N0M0), group 2 (T1-3NXM0), group 3 (T1-3N1M0), and group 4 (T1-4N0/XM1). The disease-free survival of nonmetastatic patients and the overall survival of all groups were calculated.

RESULTS

Mean age was 58.4 ± 12.0 years. Median survival for Group 1 could not be reached. Median survival was 89 months in Group 2, 50 months in Group 3, and 39 months in Group 4 (P <0.001). There was no statistically significant difference between the N1 and M1 groups (P = 0.297). For the NX patient group without LND, median survival was 89 months, which is worse than the N0 group and better than the N1 group (P = 0.002).

CONCLUSIONS

Our study presumes that the patients without LND are not staged sufficiently, NX patients have worse survival rates when compared with N0 patients, node-positive patients have poor survival rates as do the metastatic patients, and it should be defined as TNM stage4.

Impact of pathologic lymph node-positive renal cell carcinoma on survival in patients without metastasis: Evidence in support of expanding the definition of stage IV kidney cancer

BACKGROUND

Stage III renal cell carcinoma (RCC) encompasses both lymph node-positive (pT1-3N1M0) and lymph node-negative (pT3N0M0) disease. However, prior institutional studies have indicated that among patients with stage III disease, those with lymph node disease have worse oncologic outcomes and experience survival that is similar to that of patients with American Joint Committee on Cancer (AJCC) stage IV disease. The objective of the current study was to validate these findings using a large, nationally representative sample of patients with kidney cancer.

METHODS

Patients with AJCC stage III or stage IV RCC were identified using the National Cancer Data Base (NCDB). Patients were categorized as having lymph node-positive stage III (pT1-3N1M0), lymph node-negative stage III (pT3N0M0), or stage IV metastatic (pT1-3 N0M1) disease. Cox proportional hazards models compared outcomes while adjusting for comorbidities. Kaplan-Meier estimates illustrated relative survival when comparing staging groups.

RESULTS

A total of 8988 patients met the inclusion criteria, with 6587 patients classified as having lymph node-negative stage III disease, 2218 as having lymph node-positive stage III disease, and 183 as having stage IV disease. Superior survival was noted among patients with lymph node-negative stage III disease, but similar survival was noted between patients with lymph node-positive stage III and stage IV RCC, with 5-year survival rates of 61.9% (95% confidence interval [95% CI], 60.3%-63.4%), 22.7% (95% CI, 20.6%-24.9%), and 15.6% (95% CI, 11.1%-23.8%), respectively.

CONCLUSIONS

Current RCC staging systems group pT1-3N1M0 and pT3N0M0 disease as stage III disease. However, the results of the current validation study suggest the need for further stratification and even placement of patients with pT1-3N1M0 disease into the stage IV category. Staging that accurately reflects oncologic prognosis may help clinicians better counsel and select patients who might derive the most benefit from lymphadenectomy, adjuvant systemic therapy, more rigorous imaging surveillance, and clinical trial participation.

To Be or "Node" to Be: Nodal Disease and the Role of Lymphadenectomy in the Treatment of Renal Cell Carcinoma

Lymph node involvement in renal cell carcinoma (RCC) correlates with poor oncologic outcomes. However, current RCC staging guidelines may not fully reflect the survival impact of lymph node positive disease. Recent data demonstrates that nodal disease has significant impact on survival and modifications to current staging guidelines have been proposed. Lymph node dissection (LND) at the time of surgical intervention for RCC remains controversial. While clinical trial data have demonstrated conflicting evidence for LND, some institutional studies suggests that carefully selected patients at high-risk for recurrence may benefit from LND. Prospectively, clinical trials are examining treating nodal disease and disease at high-risk of recurrence in the neoadjuvant and/or adjuvant setting at the time of nephrectomy. These promising trials are poised, if successful, to influence the treatment paradigm for localized RCC.

Nodular Vascular Transformation of the Lymph Node Sinuses Mimicking Sarcomatoid Change in Renal Cell Carcinoma: A Potential Diagnostic Pitfall

Vascular transformation of the lymph node sinuses (VTS) is an uncommon phenomenon that is believed to occur secondary to obstruction of efferent lymphatics, frequently occuring in retroperitoneal lymph nodes draining cancer. The nodular subtype of VTS, in particular, can mimic metastatic cancer, such as metastatic renal cell carcinoma with sarcomatoid differentiation, potentially resulting in inaccurate tumor grading and/or staging. We present a case of nodular VTS mimicking metastatic renal cell carcinoma with sarcomatoid differentiation in a patient with high-grade clear cell renal cell carcinoma, and explore the relevant differential diagnosis. Awareness of VTS is essential to avoid misdiagnosis of this benign and curative condition.

Reassessment of American Joint Committee on Cancer Staging for Stage III Renal Cell Carcinoma With Nodal Involvement: Propensity Score Matched Analyses of a Large Population-Based Study

Background: To assess the role of nodal involvement in stage III renal cell carcinoma (RCC) according to the American Joint Committee on Cancer (AJCC) 8th staging system. We compared the survival outcomes of RCC patients with pT1-3N1M0 disease and those with pT3N0M0 or stage IV (stratified as pT4NanyM0 and pTanyNanyM1) disease in a large population-based cohort. Methods: A cohort of 3,112 eligible patients with RCC was identified from the Surveillance, Epidemiology, and End Results (SEER) database, registered between January 2004 and December 2015. Kaplan-Meier and Cox proportional hazards models were used to evaluate the overall survival (OS), and cancer-specific survival (CSS). The prognostic value of the modified stage for pT1-3N1M0 disease was assessed by nomogram-based analyses. Propensity score matching (PSM) was used to adjust for potential baseline confounding. Results: Patients with pT1-3N1M0 disease showed similar survival outcomes (median OS 41.0 vs. 38.0 months, P = 0.77; CSS 45.0 vs. 39.0 months, P = 0.59) to pT4NanyM0 patients, whereas the significantly better survival outcome was found for pT3N0M0 patients. After PSM, comparable survival rates were observed between pT1-3N1M0 group and pT4NanyM0 group, which were still significantly worse than the survival of pT3N0M0 patients. The modified stage IIIA (pT3N0M0), IIIB (pT1-3N1M0, pT4NanyM0), and IV (pTanyNanyM1) showed higher predictive accuracy than AJCC stage system in the nomogram-based analyses (concordance index: 0.70 vs. 0.68, P < 0.001 for OS; 0.71 vs. 0.69, P < 0.001 for CSS). Conclusions: The pT1-3N1M0 RCC might be reclassified as stage IIIB together with pT4NanyM0 disease for better prediction of prognosis, further examination and validation are warranted.

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.

Lymph Node Density as an Independent Prognostic Factor in Node-Positive Renal-Cell Carcinoma: Results From the Surveillance, Epidemiology, and End Results Program

BACKGROUND

Previous studies have revealed lymph node density (LND) to be an independent prognostic factor in cancer. However, data from 20 years ago failed to demonstrate the prognostic value of LND in node-positive renal-cell carcinoma (RCC). This study was undertaken to comprehensively investigate the prognostic value of LND in node-positive RCC.

PATIENTS AND METHODS

Within the Surveillance, Epidemiology and End Results database, we accessed data on patients diagnosed with histologically confirmed node-positive RCC from 2004 to 2014. The cubic spline smoothing technique and Cox regression were used to evaluate the correlation between LND and cancer-specific mortality (CSM). The X-Tile program was used to identify the optimal cut point of LND in node-positive RCC. Robustness of the results in various subgroups was also explored. Univariable and multivariable analyses were performed to determine predictors of CSM. Sensitivity analyses were performed.

RESULTS

A total of 1750 node-positive RCCs were identified. We found a nonlinear positive correlation between the likelihood of CSM and LND. X-Tile analysis identified best cut point of LND as 35% with a maximum chi-square of 18.58. Every 10% increase in LND increased CSM by 5% (hazard ratio = 1.05; 95% confidence interval, 1.02-1.07; P < .0001), and LND ≥ 35% was associated with 41% increase in CSM (hazard ratio = 1.41; 95% confidence interval, 1.20-1.65; P < .0001) in fully adjusted Cox regression. Results of sensitivity analyses were consistent with those of the primary analysis.

CONCLUSION

LND is an independent prognostic factor in node-positive RCC and should be incorporated into the cancer staging system.