Clinicopathologic findings predictive of relapse in children with stage III favorable-histology Wilms tumor

Lymph Node Sampling in Pediatric Renal Tumors: Survey of Current Practices and Impact of Education

OBJECTIVE

To characterize how often and to what extent surgeons are willing to perform retroperitoneal node sampling (RPLNS) for a unilateral renal tumor, and whether they would be encouraged to change goal number of LNs after "targeted education" (TE) METHODS: A survey with selected demographic and LN sampling practice questions was distributed to practicing members of the Society of Pediatric Urology (SPU). After answering a 7-question questionnaire, participants were provided with an abstract on the adequacy of LN yield for staging. This served as the TE and then participants were asked to answer a final question on LN sampling goals.

RESULTS

A total of 76 (19.2%) of participants, out of 395 invitations, returned complete surveys. Cross tabulation between sampling goals before and after TE showed that among surgeons sampling 1-4 nodes, 13/24 (54.16%) would be willing to change their practice and sample ≥10 nodes. A higher proportion of participants who were already systematically surveilling 5-9 LNs would be willing to change their current practice: 30/39 (77%) would now aim for ≥10 LNs. On multivariate analysis, only willingness to sample ≥5 LNs in current practice was predictive of changing to sample ≥10 LNs after TE.

CONCLUSION

Retroperitoneal LNs are currently still under sampled by pediatric urologists operating on children and adolescents with unilateral renal tumors. TE appears to encourage change in LN sampling practices.

Intraparenchymal Indocyanine Green Use Improves Nodal Yield During Minimally Invasive Tumor Nephrectomy in Children

Introduction: Correctly identifying positive lymph nodes associated with pediatric renal tumors is key to guiding management. Recommended targets for lymph node sampling are commonly missed during tumor nephrectomy, particularly if minimally invasive surgery (MIS) is performed. Indocyanine green (ICG) is used for lymph node mapping in adult oncology with excellent efficacy and safety profile. Materials and Methods: A prospective study was undertaken at a single-quaternary-level pediatric surgery center. All patients undergoing MIS radical or partial nephrectomy for renal tumors 2016-2023 were included. Patients managed from 2020 onwards received intra-parenchymal ICG prior to lymph node sampling. Main Results: Twenty-five patients underwent MIS nephrectomy at mean age 2 years 10 months. Eighteen patients were pre-ICG and 7 received ICG. ICG administration successfully demonstrated fluorescent nodes in all patients. Median number of nodes sampled was three pre-ICG and seven with ICG (P = 0.009). Forty-six nodes were sampled across 7 ICG patients-33 fluorescent, 10 non-fluorescent, and 3 identified histologically. Three nodes overall contained active disease, two pre-ICG and one fluorescent node with ICG. Neither operative time (180 pre-ICG versus 161 minutes ICG, P = 0.7) nor length of stay (72 versus 84 hours, P = 0.3) were significantly affected by ICG administration. There were no adverse events associated with ICG use. Conclusions: ICG is safe and effective at identifying nodes in MIS resection of pediatric renal tumors with the potential to increase the number of nodes sampled. Further research is needed, specifically a randomized control trial with extended follow-up.

Insights into Personalized Care Strategies for Wilms Tumor: A Narrative Literature Review

Wilms tumor (WT), or nephroblastoma, is the predominant renal malignancy in the pediatric population. This narrative review explores the evolution of personalized care strategies for WT, synthesizing critical developments in molecular diagnostics and treatment approaches to enhance patient-specific outcomes. We surveyed recent literature from the last five years, focusing on high-impact research across major databases such as PubMed, Scopus, and Web of Science. Diagnostic advancements, including liquid biopsies and diffusion-weighted MRI, have improved early detection precision. The prognostic significance of genetic markers, particularly WT1 mutations and miRNA profiles, is discussed. Novel predictive tools integrating genetic and clinical data to anticipate disease trajectory and therapy response are explored. Progressive treatment strategies, particularly immunotherapy and targeted agents such as HIF-2α inhibitors and GD2-targeted immunotherapy, are highlighted for their role in personalized treatment protocols, especially for refractory or recurrent WT. This review underscores the necessity for personalized management supported by genetic insights, with improved survival rates for localized disease exceeding 90%. However, knowledge gaps persist in therapies for high-risk patients and strategies to reduce long-term treatment-related morbidity. In conclusion, this narrative review highlights the need for ongoing research, particularly on the long-term outcomes of emerging therapies and integrating multi-omic data to inform clinical decision-making, paving the way for more individualized treatment pathways.

Nomogram for personalized prognostic assessment of children with favorable histology Wilms tumor: A retrospective analysis

OBJECTIVE

This retrospective study aimed to construct and validate a nomogram for personalized prognostic assessment of favorable histology Wilms tumor (FHWT) based on clinical and pathological variables.

METHODS AND MATERIALS

This was a retrospective study collected data from patients who underwent surgery for FHWT between March 2007 and November 2022 at Beijing Children's Hospital. Univariate and multivariate Cox proportional hazards regression analyses were conducted to determine the significance variables and constructed the nomogram in predicting event-free survival (EFS) in FHWT patients.

RESULTS

A total of 401 FHWT patients were included in the study, with the median age of the patients was 3.4 years. The overall 1-, 3-, and 5-year OS rates were 98.2%, 96.3%, and 93.9%. The 1-, 3-, and 5-year EFS rates were 91.2%, 88.2%, and 86.6%. Subgroup analysis revealed age greater than 2 years was associated with a worse prognosis than age less than or equal to 2 years (P < 0.001), and patients with high-risk Wilms tumors were associated with a higher rate of recurrence and death (P < 0.001). Multivariate analysis showed that age (HR: 2.449, 95%CI: 1.004-5.973), stage (HR: 1.970, 95% CI:1.408-2.756), and histological risk (HR:9.414, 95% CI: 4.318-20.525) were identified as independent predictors of EFS (P < 0.05) and used to construct the nomogram. The prognostic nomogram demonstrated good calibration, great clinical utility, and the time-dependent receiver operating curve analysis showed that the nomogram had precise predictability, with area under the curve values of 0.85(95CI:0.796-0.913), 0.85(95CI:0.80-0.91), and 0.88(95CI:0.839-0.937) for 1-,3-year and 5-year EFS.

CONCLUSION

This study provides valuable insights into the clinical characteristics and outcomes of FHWT patients. Accurate staging and histological risk assessment are important in predicting outcomes, and the prognostic nomogram we developed can be a useful tool for clinicians to assess patient prognosis and make informed treatment decisions.

Current surgical approaches to pediatric renal tumors

Pediatric renal tumors are among the most common pediatric solid malignancies. Surgical resection is a key component in the multidisciplinary therapy for children with kidney tumors. Therefore, it is imperative that surgeons caring for children with renal tumors fully understand the current standards of care in order to provide appropriate surgical expertise within this multimodal framework. Fortunately, the last 60 years of international, multidisciplinary pediatric cancer cooperative group studies have enabled high rates of cure for these patients. This review will highlight the international surgical approaches to pediatric patients with kidney cancer to help surgeons understand the key differences and similarities between the European (International Society of Pediatric Oncology) and North American (Children's Oncology Group) recommendations.

Systematic Review and Meta-analysis of Laparoscopic Versus Open Radical Nephrectomy for Paediatric Renal Tumors With Focus on Wilms' Tumor

OBJECTIVE

To summarize and evaluate the outcomes of laparoscopic radical nephrectomy (LRN) and compare its safety and efficacy with open radical nephrectomy (ORN) in pediatric renal tumors (RT) and Wilms' tumors (WT).

BACKGROUND

ORN is the gold standard treatment for pediatric RT, consisting predominantly of WT. LRN is gaining popularity but remains controversial in pediatric surgical oncology.

METHODS

A systematic search was performed for all eligible studies on LRN and comparative studies between LRN and ORN in pediatric RT and WT. Meta-analysis, subgroup analysis, and sensitivity analysis were conducted. The main endpoints were cancer-related outcomes and surgical morbidity. Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines were followed.

RESULTS

No levels I to II studies were identified. LRN was feasible in nearly 1 in 5 pediatric RT and WT after neoadjuvant chemotherapy, with pooled mid-term oncological outcomes (<7% local recurrence, >90% event-free survival) comparable with those of ORN. There was no strong evidence of an increased risk of intraoperative tumor spillage, but lymph node harvest was inadequate in LRN. Large tumors crossing the ipsilateral spinal border were associated with a trend for intraoperative complications and positive margins. Pooled complications rate and hospital stay duration were similar between LRN and ORN. Long-term (>3 years) outcomes are unknown.

CONCLUSIONS

Available level III evidence indicates that LRN is a safe alternative to ORN for carefully selected cases, with similar spillage rates and mid-term oncological outcomes. However, there was no advantage in surgical morbidity and lymph node harvest was inadequate with LRN. Tumor-matched-group studies with long-term follow-up are required.

LEVEL OF EVIDENCE

Level III.

Prognostic role of primary tumor size in Wilms tumor

Wilms tumor (WT) is the most common childhood malignant kidney tumor. The aim of the present study was to determine the impact of primary tumor size on the survival of patients with WT. The data of 1,523 patients diagnosed with WT between 2000 and 2017 were retrieved from the Surveillance, Epidemiology, and End Results database. Receiver operating characteristic curves were plotted to determine the optimal cut-off value of primary tumor size. Overall survival (OS) and cancer-specific survival (CSS) were analyzed using the Kaplan-Meier method and the Cox proportional hazards regression model. The optimal cut-off value for primary tumor size was found to be 11.15 cm. No significant difference in the distribution of tumor size was detected between male and female patients. However, lymph node metastasis and distant metastasis were significantly more frequent in patients whose tumor was ≥11.15 cm in size compared with those with smaller tumors. In addition, patients with larger tumors exhibited significantly worse OS and CSS rates compared with those with smaller tumors. Furthermore, primary tumor size was identified as an independent prognostic factor for OS and CSS in the multivariate analyses. In summary, the present study indicates that primary tumor size is an independent prognostic factor for patients with WT, and tumors ≥11.15 cm are associated with worse OS and CSS.

Prognostic impact of lymph node involvement and loss of heterozygosity of 1p or 16q in stage III favorable histology Wilms tumor: A report from Children's Oncology Group Studies AREN03B2 and AREN0532

INTRODUCTION

The prognostic impact of positive lymph nodes (LN+) and/or singular loss of heterozygosity (LOH) of 1p or 16q were assessed in children with stage III favorable histology Wilms tumor (FHWT) enrolled on AREN0532 or AREN03B2 alone.

PATIENTS AND METHODS

A total of 635 stage III FHWT vincristine/dactinomycin/doxorubicin (DD4A)-treated patients met inclusion criteria. Event-free survival (EFS) and overall survival are reported overall and by LN sampling, LN status, LOH 1p, LOH 16q, and a combination of LN status and singular LOH. Patients with unknown or positive combined LOH of 1p and 16q status and AREN03B2-only patients with unknown outcomes or treatment other than DD4A were excluded.

RESULTS

EFS did not differ by study, supporting pooling. Lack of LN sampling (hazard ratio [HR], 2.12; p = .0037), LN positivity (HR, 2.78; p = .0002), LOH 1p (HR, 2.18; p = .0067), and LOH 16q (HR, 1.72; p = .042) were associated with worse EFS. Compared with patients with both LN- and LOH-, those with negative nodes but positive LOH 1p or 16q and those with LN+ but LOH- for 1p or 16q had significantly worse EFS (HR, 3.05 and 3.57, respectively). Patients positive for both LN and LOH had the worst EFS (HR, 6.33; overall group factor, p < .0001).

CONCLUSION

Findings confirm LN+ status as an adverse prognostic factor amplified by presence of singular LOH 1p or 16q, supporting study of intensified therapy for patients with LN+ in combination with singular LOH in a prospective clinical trial.

A review on optimization of Wilms tumour management using radiomics

Background

Wilms tumour, a common paediatric cancer, is difficult to treat in low- and middle-income countries due to limited access to imaging. Artificial intelligence (AI) has been introduced for staging, detecting, and classifying tumours, aiding physicians in decision-making. However, challenges include algorithm accuracy, translation into conventional diagnosis, reproducibility, and reliability. As AI technology advances, radiomics, an AI tool, emerges to extract tumour morphology and stage information.

Objectives

This review explores the application of radiomics in Wilms tumour management, including its potential in diagnosis, prognosis, and treatment. Additionally, it discusses the future prospects of AI in this field and potential directions for automation-aided Wilms tumour treatment.

Methods

The review analyses various research studies and articles on the use of radiomics in Wilms tumour management. This includes studies on automated deep learning-based classification, interobserver variability in histopathological analysis, and the application of AI in staging, detecting, and classifying Wilms tumours.

Results

The review finds that radiomics offers several promising applications in Wilms tumour management, including improved diagnosis: it helps in classifying Wilms tumours from other paediatric kidney tumours, prognosis prediction: radiomic features can be used to predict both staging and response to preoperative chemotherapy, Treatment response assessment: Radiomics can be used to monitor the response of Wilms and to predict the feasibility of nephron-sparing surgery.

Conclusions

This review concludes that radiomics has the potential to significantly improve the diagnosis, prognosis, and treatment of Wilms tumours. Despite some challenges, such as the need for further research and validation, AI integration in Wilms tumour management offers promising opportunities for improved patient care.

Advances in knowledge

This review provides a comprehensive overview of the potential applications of radiomics in Wilms tumour management and highlights the significant role AI can play in improving patient outcomes. It contributes to the growing body of knowledge on AI-assisted diagnosis and treatment of paediatric cancers.

Critical elements of radical nephroureterectomy for pediatric unilateral renal tumor

Children with renal masses require surgical management to provide accurate surgical staging and skilled resection of the tumor. This document includes evidence-based recommendations for pediatric surgeons regarding the resection, staging, and proper nodal basin evaluation.

Extended Lymph Node Sampling During Surgery for Pediatric Renal Tumors Concerning for Malignancy Does Not Increase Postoperative Complication Rates

PURPOSE

Although Children's Oncology Group renal tumor protocols mandate lymph node sampling during extirpative surgery for pediatric renal tumors, lymph node sampling is often omitted or low yield. Concerns over morbidity associated with extended lymph node sampling have led to hesitancy in adopting a formal lymph node sampling template. We hypothesized that complications in children undergoing lymph node sampling for renal tumors would be rare, and not associated with the number of lymph nodes sampled.

MATERIALS AND METHODS

A single-institution, retrospective review of patients aged 0-18 years undergoing extirpative renal surgery with lymph node sampling for a suspected malignancy between 2005 and 2019 was performed. Patients with 0 or an unknown number of lymph nodes sampled or <150 days of follow-up were excluded. A "clinically significant" complication was defined as any Clavien complication ≥III, small-bowel obstruction, chylous ascites, organ injury, or wound infection. The number of lymph nodes sampled and its influence on the odds of experiencing a clinically significant complication was examined.

RESULTS

A total of 144 patients met inclusion criteria. Median patient age was 38 months. Twenty-one patients (15%) had a clinically significant complication, the most common of which was ileus/small-bowel obstruction (n=16). In a multivariable analysis, increased lymph node yield was not found to influence the odds of experiencing a clinically significant complication (P = .6).

CONCLUSIONS

In this cohort, there was no statistically significant difference in clinically significant complications in patients who underwent more extensive lymph node sampling during surgery for a suspected malignant pediatric renal tumor. Future studies on protocol adherence, staging accuracy, and survival trends using a lymph node sampling template in these patients should be performed.

Outcomes of patients with Wilms' tumour stage III due to positive resection margins only: An analysis of patients treated on the SIOP-WT-2001 protocol in the UK-CCLG and GPOH studies

Stage III Wilms' tumour (WT) represents a heterogeneous group which includes different criteria, but all stage III patients are treated according to the same study regiment. The aim of the study was to retrospectively analyse outcomes in patients with stage III due to positive resection margins (RM) only, sub-grouped in RM with viable (RM-v) and nonviable (RM-nv) tumour. Patients were treated pre- and postoperatively according to the SIOP-WT-2001 protocol in the UK-CCLG and GPOH WT trials and studies (2001-2020). There were 197 patients, including 134 with localised, abdominal stage III and 63 with overall stage IV, but abdominal stage III. Stage III due to RM-v had 126 patients, and due to RM-nv 71 patients. The overall 5-year local-relapse-free survival (RFS), event-free (EFS) and overall survival (OS) estimates for all patients with abdominal stage III RM were 95.7% (±SE1.5%), 85.1 (±SE2.6%) and 90.3% (±SE2.2%), respectively. Patients with stage III RM-nv had significantly better RFS and EFS than patients with RM-v (P = .027 and P = .003, respectively). A multivariate analysis showed that RM-v remained a significant factor for EFS when adjusted for age, presence of metastasis at diagnosis, histological risk group and overall stage in Cox regression analysis (P = .006). Patients with stage III due to RM-nv only exhibited no local recurrence and have a significantly better RFS and EFS than patients with RM-v. The results suggest that exclusion of RM-nv as a stage III criterion in the UMBRELLA staging system and consequent treatment reduction is warranted.

Number of lymph nodes sampled in SFCE/SIOP 2001 patients with Wilms tumour: Is the goal of more than six achievable?

AIM

The number of lymph nodes (LN) that should be sampled during nephrectomy for Wilms tumour (WT) remains controversial but of utmost importance for staging purposes. The aim of this French national retrospective study of patients enrolled in SIOPWT2001 trial was to analyse the number of LN sampled according to their site and to determine if the number of six asked by the International Society of Paediatric Oncology - Renal Tumour Study Group (SIOP-RTSG) UMBRELLA protocol is achievable.

METHODS

We reviewed the data collected on central pathology review forms from 2002 to 2014 for only unilateral WT. LN were divided whether they were clearly identified by surgeons at nephrectomy or only found by pathologists on the nephrectomy specimen.

RESULTS

A total of 539 patients (240 male/299 female) were included (458 localized/81 metastatic). Median age at surgery was 41.3 months [0-189]. The number of LN sampled was 0, 1-6, ≥7 and unknown in 69 (12.8%), 293 (54.3%), 160 (29.7%) and 17 (3.2%) cases, respectively. The number of patients with sampled LN were higher if LN were identified by both the pathologist and the surgeon (n = 231, 42.8%) (p = < .001). At least one invaded LN (LN+) was found in 66 patients (12.2%), more than half being found among patients having LN sampled by both pathologist and surgeon (p < .001). The mean number of identified LN was six if no LN+ was detected on final histological analysis, while it was 11 in case of LN+ (p < .001).

CONCLUSIONS

The aim of sampling more than six LN is achievable, but only with the active collaboration of both surgeons and pathologists.

Evidence-based surgical guidelines for treating children with Wilms tumor in low-resource settings

BACKGROUND

Survival of Wilms tumor (WT) is > 90% in high-resource settings but < 30% in low-resource settings. Adapting a standardized surgical approach to WT is challenging in low-resource settings, but a local control strategy is crucial to improving outcomes.

OBJECTIVE

Provide resource-sensitive recommendations for the surgical management of WT.

METHODS

We performed a systematic review of PubMed and EMBASE through July 7, 2020, and used the GRADE approach to assess evidence and recommendations.

RECOMMENDATIONS

Initiation of treatment should be expedited, and surgery should be done in a high-volume setting. Cross-sectional imaging should be done to optimize preoperative planning. For patients with typical clinical features of WT, biopsy should not be done before chemotherapy, and neoadjuvant chemotherapy should precede surgical resection. Also, resection should include a large transperitoneal laparotomy, adequate lymph node sampling, and documentation of staging findings. For WT with tumor thrombus in the inferior vena cava, neoadjuvant chemotherapy should be given before en bloc resection of the tumor and thrombus and evaluation for viable tumor thrombus. For those with bilateral WT, neoadjuvant chemotherapy should be given for 6-12 weeks. Neither routine use of complex hilar control techniques during nephron-sparing surgery nor nephron-sparing resection for unilateral WT with a normal contralateral kidney is recommended. When indicated, postoperative radiotherapy should be administered within 14 days of surgery. Post-chemotherapy pulmonary oligometastasis should be resected when feasible, if local protocols allow omission of whole-lung irradiation in patients with nonanaplastic histology stage IV WT with pulmonary metastasis without evidence of extrapulmonary metastasis.

CONCLUSION

We provide evidence-based recommendations for the surgical management of WT, considering the benefits/risks associated with limited-resource settings.

Multidisciplinary Treatment Strategies for Wilms Tumor: Recent Advances, Technical Innovations and Future Directions

Significant progress has been made in the management of Wilms tumor (WT) in recent years, mostly as a result of collaborative efforts and the implementation of protocol-driven, multimodal therapy. This article offers a comprehensive overview of current multidisciplinary treatment strategies for WT, whilst also addressing recent technical innovations including nephron-sparing surgery (NSS) and minimally invasive approaches. In addition, surgical concepts for the treatment of metastatic disease, advances in tumor imaging technology and potentially prognostic biomarkers will be discussed. Current evidence suggests that, in experienced hands and selected cases, laparoscopic radical nephrectomy and laparoscopic-assisted partial nephrectomy for WT may offer the same outcome as the traditional open approach. While NSS is the standard procedure for bilateral WT, NSS has evolved as an alternative technique in patients with smaller unilateral WT and in cases with imminent renal failure. Metastatic disease of the lung or liver that is associated with WT is preferably treated with a three-drug chemotherapy and local radiation therapy. However, surgical sampling of lung nodules may be advisable in persistent nodules before whole lung irradiation is commenced. Several tumor markers such as loss of heterozygosity of chromosomes 1p/16q, 11p15 and gain of function at 1q are associated with an increased risk of recurrence or a decreased risk of overall survival in patients with WT. In summary, complete resection with tumor-free margins remains the primary surgical aim in WT, while NSS and minimally invasive approaches are only suitable in a subset of patients with smaller WT and low-risk disease. In the future, advances in tumor imaging technology may assist the surgeon in defining surgical resection margins and additional biomarkers may emerge as targets for development of new diagnostic tests and potential therapies.

Identification of CDC20 as a Novel Biomarker in Diagnosis and Treatment of Wilms Tumor

Objective: Wilms tumor (WT) is a common malignant solid tumor in children. Many tumor biomarkers have been reported; however, there are poorly targetable molecular mechanisms which have been defined in WT. This study aimed to identify the oncogene in WT and explore the potential mechanisms. Methods: Differentially expressed genes (DEGs) in three independent RNA-seq datasets were downloaded from The Cancer Genome Atlas data portal and the Gene Expression Omnibus database (GSE66405 and GSE73209). The common DEGs were then subjected to Gene Ontology enrichment analysis, protein-protein interaction (PPI) network analysis, and gene set enrichment analysis. The protein expression levels of the hub gene were analyzed by immunohistochemical analysis and Western blotting in a 60 WT sample. The univariate Kaplan-Meier analysis for overall survival was performed, and the log-rank test was utilized. A small interfering RNA targeting cell division cycle 20 (CDC20) was transfected into G401 and SK-NEP-1 cell lines. The Cell Counting Kit-8 assay and wound healing assay were used to observe the changes in cell proliferation and migration after transfection. Flow cytometry was used to detect the effect on the cell cycle. Western blot was conducted to study the changes of related functional proteins. Results: We commonly identified 44 upregulation and 272 downregulation differentially expressed genes in three independent RNA-seq datasets. Gene and pathway enrichment analyses of the regulatory networks involving hub genes suggested that cell cycle changes are crucial in WT. The top 15 highly connected genes were found by PPI network analysis. Furthermore, we demonstrated that one candidate biomarker, CDC20, for the diagnosis of WT was detected, and its high expression predicted poor prognosis of WT patients. Moreover, the area under the curve value obtained by receiver operating characteristic curve analysis from paired WT samples was 0.9181. Finally, we found that the suppression of CDC20 inhibited proliferation and migration and resulted in G2/M phase arrest in WT cells. The mechanism may be involved in increasing the protein level of securin, cyclin B1, and cyclin A Conclusion: Our results suggest that CDC20 could serve as a candidate diagnostic and prognostic biomarker for WT, and suppression of CDC20 may be a potential approach for the prevention and treatment of WT.

Imaging for Staging of Pediatric Abdominal Tumors: An Update, From the AJR Special Series on Cancer Staging

The three most common pediatric solid tumors of the abdomen are neuroblastoma, Wilms tumor, and hepatoblastoma. These embryonal tumors most commonly present in the first decade of life. Each tumor has unique imaging findings, including locoregional presentation and patterns of distant spread. Neuroblastoma, Wilms tumor, and hepatoblastoma have unique staging systems that rely heavily on imaging and influence surgical and oncologic management. The staging systems include image-defined risk factors for neuroblastoma, the Children's Oncology Group staging system for Wilms tumor, and the pretreatment extent of tumor system (PRETEXT) for hepatoblastoma. It is important for radiologists to be aware of these staging systems to optimize image acquisition and interpretation. This article provides a practical and clinically oriented approach to the role of imaging in the staging of these common embryonal tumors of childhood. The selection among imaging modalities, key findings for determining tumor stage, and the role of imaging in posttreatment response evaluation and surveil-lance are discussed. Recent updates to the relevant staging systems are highlighted with attention to imaging findings of particular prognostic importance. The information presented will help radiologists tailor the imaging approach to the individual patient and guide optimal oncologic management.

Wilms Tumor (Nephroblastoma), Version 2.2021, NCCN Clinical Practice Guidelines in Oncology

The NCCN Guidelines for Wilms Tumor focus on the screening, diagnosis, staging, treatment, and management of Wilms tumor (WT, also known as nephroblastoma). WT is the most common primary renal tumor in children. Five-year survival is more than 90% for children with all stages of favorable histology WT who receive appropriate treatment. All patients with WT should be managed by a multidisciplinary team with experience in managing renal tumors; consulting a pediatric oncologist is strongly encouraged. Treatment of WT includes surgery, neoadjuvant or adjuvant chemotherapy, and radiation therapy (RT) if needed. Careful use of available therapies is necessary to maximize cure and minimize long-term toxicities. This article discusses the NCCN Guidelines recommendations for favorable histology WT.

Impact of the First Generation of Children's Oncology Group Clinical Trials on Clinical Practice for Wilms Tumor

Refinements in surgery, radiation therapy, and chemotherapy since the mid-20th century have resulted in a survival rate exceeding 90% for patients with Wilms tumor (WT). Although this figure is remarkable, a significant proportion of patients continue to have event-free survival (EFS) estimates of <75%, and nearly 25% of survivors experience severe chronic medical conditions. The first-generation Children's Oncology Group (COG) renal tumor trials (AREN '0'), which opened to enrollment in 2006, focused on augmenting treatment regimens for WT subgroups with predicted EFS <75% to 80%, including those with the adverse prognostic marker of combined loss of heterozygosity (LOH) at chromosomes 1p/16q, pulmonary metastasis with incomplete lung nodule response after 6 weeks of chemotherapy, bilateral disease, and anaplastic histology. Conversely, therapy was reduced for patient subgroups with good outcomes and potential for long-term toxicity, such as those with lung metastasis with complete lung nodule response after 6 weeks of chemotherapy. This article summarizes the key findings of the first-generation COG renal tumor studies and their implications for clinical practice.

Prognostic Factors for Wilms Tumor Recurrence: A Review of the Literature

Simple Summary

A Wilms tumor is a childhood kidney tumor. In high-income countries, 90% of patients with this tumor survive. However, the tumor recurs in 15% of patients. It is important to identify the patients at risk of recurrence in order to adjust treatment in such a way that recurrence may potentially be prevented. However, we are currently unable to determine precisely which patients are at risk of recurrence. Therefore, we present an overview of factors that influence the risk of recurrence, also known as prognostic factors. These factors range from patient-, tumor- and treatment-related characteristics to geographic and socioeconomic factors. In addition to these factors, biological markers, such as genetic alterations, should be studied more intensively as these markers may be able to better identify patients at risk of tumor recurrence.

Abstract

In high-income countries, the overall survival of children with Wilms tumors (WT) is ~90%. However, overall, 15% of patients experience tumor recurrence. The adverse prognostic factors currently used for risk stratification (advanced stage, high risk histology, and combined loss of heterozygosity at 1p and 16q in chemotherapy-naïve WTs) are present in only one third of these cases, and the significance of these factors is prone to change with advancing knowledge and improved treatment regimens. Therefore, we present a comprehensive, updated overview of the published prognostic variables for WT recurrence, ranging from patient-, tumor- and treatment-related characteristics to geographic and socioeconomic factors. Improved first-line treatment regimens based on clinicopathological characteristics and advancing knowledge on copy number variations unveil the importance of further investigating the significance of biological markers for WT recurrence in international collaborations.

Wilms tumor

The objectives for the treatment of Wilms tumor in both the Children's Oncology Group (COG) and the International Society of Paediatric Oncology (SIOP) have focused on improving cure rates and minimizing toxicity by limiting the use of radiation and doxorubicin. Although the timing of surgery is different in COG (upfront surgery) and SIOP (upfront chemotherapy with delayed surgery), both are effective strategies and have the same survival. Fewer patients are treated with radiotherapy in the SIOP trials but with higher doses. The prognostic significance of biological markers such as 1q gain and clinical outcomes with novel radiation techniques such as intensity modulated radiation therapy will be determined in upcoming clinical trials. A closer collaboration between COG and SIOP could help promote research and improve the clinical outcomes of children with Wilms tumor.

Outcomes of event-free survival in patients with Wilms tumor undergoing preoperative chemotherapy. Analysis of lymph-node yield in a single-center cohort

INTRODUCTION

The clinical value of lymph node sampling in Wilms tumor (WT) lies in its ability to accurately determine lymph node (LN) involvement. LN yield (LNY) is used as a valuable tool to measure LN retrieval, and a minimum of 6 LNs is one of the current recommendations. In patients who are managed with the SIOP strategy, preoperative chemotherapy decreases the retrieval of LN during surgery resulting in lower LNY values.

PURPOSE

To determine the mean LNY and to analyze survival outcomes in patients with WT who underwent preoperative chemotherapy at a single center.

METHODS

We performed a retrospective chart review of all patients between 6 months and 12 years of age with unilateral WT who underwent preoperative chemotherapy between 2010 and 2018. Patients with bilateral WT or without preoperative chemotherapy were excluded. Collected data included: demographics, tumor volume, tumor histopathology, number of LNs collected (LNY), presence or absence of tumor in the retrieved LNs, and disease stage according to these results. Kaplan Meier curves were calculated to estimate 5-year event-free survival (EFS) and overall survival (OS).

RESULTS

95 patients with a median follow-up of 25 months were included in the study. A total of 19 patients underwent laparoscopic surgery. Mean LNY for the entire cohort was 3.26 (95% CI, 2.4-3.6; SD, 3.62). Six patients (6.3%) had at least one positive LN. The estimated 5-year OS was 89.3% (95% CI, 82.1%-96.5%). EFS was 79.8 (95% CI, 74.8%-84.8%). Recurrence rate was 20% (n: 19). Four patients (4.2%) developed local recurrence and 15 patients (15.7%) developed pulmonary recurrence. The initial mean LNY in patients that relapsed was 4.16 (95% CI, 2.2-5.8; SD: 4.18), which was higher than in patients who did not relapse (LNY: 3; 95% CI, 2.33-3.67; SD, 3.39). No recurrences or deaths occurred in the laparoscopic group.

DISCUSSION

The identification of a minimum LNY (i.e. threshold) to minimize the risk of harboring occult metastatic disease has been proposed to standardize the surgical procedure. Preliminary results in this study suggest that a limited LNY with acceptable survival outcomes is a possible scenario in patients treated according to the SIOP protocol. Systematic LN sampling to reduce the rate of false negatives is still strongly recommended.

CONCLUSION

Our cohort presented with a relatively low LNY compared to standard recommendations. Our EFS, however, remained acceptable. Multivariate analysis would be necessary to determine the actual role of LN sampling as an isolated prognostic factor in unilateral WT.

A long non-coding RNAs expression signature to improve prognostic prediction of Wilms tumor in children

BACKGROUND

Wilms tumor (WT) is the most frequent malignancy of the kidney in children, and a subset of patients remains with a poor prognosis. This study aimed to identify key long non-coding RNAs (lncRNAs) related to prognosis and establish a genomic-clinicopathologic nomogram to predict survival in children with WT.

METHODS

Clinical data of 124 WT patients and the relevant RNA sequencing data including lncRNAs expression signature of primary WT samples were obtained from the Therapeutically Applicable Research to Generate Effective Treatment (TARGET) Data Matrix. Then, lncRNAs associated with overall survival (OS) were identified through univariate Cox, least absolute shrinkage and selection operator (LASSO), and multivariate Cox regression analyses. The risk scores of 124 participants were calculated, and survival analyses were performed between low- and high-risk groups. A genomic-clinicopathologic nomogram was then developed and evaluated by time-dependent receiver operating characteristic (ROC) curves, including the area under the curve (AUC), calibration curve, and decision curve analysis. Subsequently, bioinformatics analyses were performed to explore the potential molecular mechanisms that affect the prognosis of WT. The package "DESeq2" was used to identify differentially expressed protein-coding genes (DEPCGs) between groups. Gene Set Enrichment Analysis (GSEA) was applied to explore the differences in pathways enrichment. The analytical tools CIBERSORTx and ESTIMATE were used to investigate the discrepancies of the immune microenvironment.

RESULTS

A total of 10 lncRNAs were selected as independent predictors associated with OS (P<0.05). Participants in the high-risk group had a significantly worse OS and event-free survival (EFS) than those in the low-risk group (P<2E-16 and P=2.03E-04, respectively). The risk score and 3 clinicopathological features (gender, cooperative group protocol, and stage) were identified to construct the nomogram (combined model) (P=5.11E-17). The combined model (1-year AUC: 0.9272, 3-year AUC: 0.9428, 5-year AUC: 0.9259) and risk score model (1-year AUC: 0.9285, 3-year AUC: 0.9399, 5-year AUC: 0.9266) displayed higher predictive accuracy than that of the other models. Subsequently, 105 DEPCGs were identified. The GSEA revealed 4 significant pathways. Analysis with CIBERSORTx demonstrated that monocytes, macrophages M1, activated dendritic cells, and resting mast cells had significant infiltration differences between groups.

CONCLUSIONS

This study constructed a genomic-clinicopathologic nomogram, which might present a novel and efficient method for treating patients with WT.

New approaches to risk stratification for Wilms tumor

PURPOSE OF REVIEW

The treatment of Wilms tumor is one of the great achievements in the field of oncology. One of the key success factors has been improved risk stratification, enabling augmentation or reduction of therapy depending on a patient's risk of relapse. This article highlights the evolution of clinical and biological prognostic markers that have been applied in the treatment of Wilms tumor.

RECENT FINDINGS

Historically, tumor stage and histology were the sole determinants of Wilms tumor treatment. Recent clinical trials conducted by the Children's Oncology Group (COG) and the International Society of Pediatric Oncology (SIOP) Renal Tumor Study Group have expanded the menu of prognostic factors to include histologic and volumetric response to therapy and tumor-specific loss of heterozygosity (LOH) at chromosomes 1p and 16q. Augmentation of therapy has been able to overcome the adverse risk factors. An emerging prognostic marker is chromosome 1q gain, will be incorporated into future clinical trials.

SUMMARY

The application of new clinical and biological prognostic factors has created unprecedented ability to tailor therapy for Wilms tumor, accompanied with improved outcomes. Current and future trials will continue to enhance precision medicine for Wilms tumor.

Surgical Management of Wilms Tumor (Nephroblastoma) and Renal Cell Carcinoma in Children and Young Adults

This article reviews the epidemiology, pathophysiology, clinical presentation, and multimodality management of Wilms tumors and renal cell carcinoma in pediatric and young adults. Key renal Société Internationale d'Oncologie Pédiatrique and Children Oncology Group studies are presented. The article reviews the common staging systems and risk-adapted treatment strategies with particular attention to the surgical management.

Standardizing lymph nodal sampling for Wilms tumor: A feasibility study with outcomes

BACKGROUND

Despite being mandated by cooperative groups, omission of nodal sampling is the most frequent protocol deviation in surgery for Wilms tumor. The stations as well as the number of nodes that should be sampled are not clearly defined resulting in a marked variation in practices among surgeons. We propose a systematic method for nodal sampling intending to reduce interoperator variation. In this study, we have assessed the feasibility and yield of systematic lymph node sampling and also evaluated the factors influencing nodal metastasis.

METHODS

Prospective evaluation of 113 Wilms tumor patients operated at a single tertiary cancer center between 2015 and 2019. All these patients underwent a systematic 5-station nodal sampling.

RESULTS

Median lymph node yield was 8 and 13.2% (15/113) patients harbored a histologically positive nodal disease. Of the patients with positive nodal disease, interaortocaval nodes had metastasis in 46.7% (n = 7). They represented isolated sites of nodal disease (skip metastases) in 28.6% (n = 4) of patients. Right-sided tumors had more frequent involvement of interaortocaval nodes and skip disease. Tumors with high-risk histology had 12.5 times more odds of harboring nodal disease as compared to low and intermediate-risk histology Wilms tumor.

CONCLUSIONS

The proposed method of systematic station wise sampling provides a template to guide surgeons in performing lymph node harvesting. Interaortocaval nodes sampling should be performed routinely as the incidence of disease at this station is sufficiently high and metastasis may skip hilar nodes.

STUDY OF DIAGNOSTIC TEST

Level III evidence.

Minimally invasive surgery for pediatric renal tumors: A systematic review by the APSA Cancer Committee

Minimally invasive nephrectomy is performed routinely for adult renal tumors and for many benign pediatric conditions. Although open radical nephroureterectomy remains the standard of care for Wilms tumor and most pediatric renal malignancies, there are an increasing number of reports of minimally invasive surgery (MIS) for those operations as well. The APSA Cancer Committee performed a systematic review to better understand the risks and benefits of MIS in pediatric patients with renal tumors.

METHODS

The search focused on MIS for renal tumors in children and followed the Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) checklist. The initial database search identified 491 published articles, and after progressive review of abstracts and full-length articles, 19 were included in this review.

RESULTS

There were two direct comparison studies where open surgery and MIS were compared. The remaining studies reported only on minimally invasive nephrectomy. Across all studies, there were a total of 151 patients, 126 of which had Wilms tumor and 10 patients had RCC. 104 patients had MIS, with 47 patients having open surgery. In the two studies in which open surgery and MIS were directly compared, more lymph nodes were harvested during open surgery (median = 2 (MIS) vs 5 (open); mean = 2.47 (MIS) vs 3.8 (open)). Many noncomparison studies reported the harvest of 2 of fewer lymph nodes for Wilms tumor. Several MIS patients were also noted to have intraoperative spill or positive margins. Survival between groups was similar.

CONCLUSIONS

There is a lack of evidence to support MIS for pediatric renal tumors. This review demonstrates that lymph node harvest has been inadequate for MIS pediatric nephrectomy and there appears to be an increased risk for intraoperative spill. Survival data are similar between groups, but follow-up times were inconsistent and patient selection was clearly biased, with only small tumors being selected for MIS.

TYPE OF STUDY

Review article.

LEVEL OF EVIDENCE

III.

Localized Wilms' tumor in low-middle-income countries (LMIC): how can we get better?

BACKGROUND

Wilms' tumor (WT) represents about 6% of all childhood cancers. The overall survival markedly improved to exceed 90% in developed countries, yet some studies from developing counties still have poorer outcomes. The aim of this study is to assess the clinical outcome and the different prognostic factors that influence the outcome of pediatric loco-regional WT cases treated at National Cancer Institute (NCI), Cairo University, Egypt. This is a retrospective study which included pediatric loco-regional WT patients presented between January 2008 and December 2017. Patients were followed up till June 2019.

RESULTS

Ninety-two eligible patients were included. Median age was 3 years (range 1 month-9 years). Abdominal mass was the commonest presentation (72.8%). The 5-year EFS and OS of the whole group was 83.7% and 94.6% retrospectively. Despite having a similar EFS (84.8 vs. 82.6%), stage III patients had a significantly lower OS than those in stages I and II (89.1% vs. 100%, p value 0.024). Twelve patients had unfavorable histology and had a significantly lower EFS and OS than the patients with favorable histology (50 and 83.3% vs. 88.8 and 96.3%, p value < 0.001 and 0.043, respectively).

CONCLUSION

Loco-regional Wilms' tumor cases treated in Egypt had OS nearly the same as in developed countries, but had a lower EFS than expected mainly stages I and II. The stage and histological type are the main factors influencing the survival, and further studies are needed to investigate nuclear unrest grades and proper management of such cases.

Impact of local control and surgical lymph node evaluation in localized paratesticular rhabdomyosarcoma: A report from the Children's Oncology Group Soft Tissue Sarcoma Committee

Paratesticular rhabdomyosarcoma (PT-RMS) carries a favorable prognosis, but questions persist regarding optimal management. Our goal was to determine the importance of primary tumor resection and surgical assessment of retroperitoneal lymph nodes during staging in patients with PT-RMS. We analyzed patients with localized PT-RMS enrolled onto one of four Children's Oncology Group studies (D9602, ARST0331, D9803 or ARST0531). Surgical resection of the primary tumor prior to chemotherapy and radiotherapy was encouraged when possible with retroperitoneal lymph node dissection (RPLND) recommended for patients ≥10 years of age. Among 279 patients (median 8.1 years old), most tumors were resected with negative margins (78.5%) and most patients did not have radiographic enlargement of regional lymph nodes (90.3%). In patients older than 10 years, imaging alone will miss over 51.5% of nodal disease. Five-year event-free survival (EFS) was 92.0% (95% CI 88.4%-95.6%). Sampling ≥7 to 12 retroperitoneal lymph nodes appeared optimal for detecting positive nodes; while there was a trend toward improved EFS among those undergoing template RPLND, this was not statistically significant (P = .068). Age (P = .28), N-stage (P = .39), T-stage (P = .11) and pathologic node involvement (P = .53) were not associated with overall survival. However, older age and larger tumor size had an additive impact on EFS (P = .027) though not overall survival (P = .13). In conclusion, outcomes for patients with PT-RMS are excellent. Reliance on imaging to detect nodal involvement will miss pathologic node involvement and may result in undertreatment. Surgical nodal staging requires at least 7 to 12 nodes to accurately identify patients with regional nodal disease.

A decision tree to guide long term venous access placement in children and adolescents undergoing surgery for renal tumors

BACKGROUND/PURPOSE

While many children with renal tumors require long term venous access (VA) for adjuvant chemotherapy, certainly not all do. This study develops and tests a VA decision tree (DT) to direct the placement of VA in patients with renal tumors.

METHODS

Utilizing data readily available at surgery a VADT was developed. The VADT was tested retrospectively by 2 independent reviewers on a historic cohort. The ability of the VADT to appropriately select which patients would benefit from VA placement was tested.

RESULTS

160 patients underwent renal tumor surgery between 2005 and 2018. 70 (43.8%) patients met study criteria with median age of 45.1 months (range 1.1-224); 73% required VA. Using the VADT, VA placement was "needed" in 67.1% of patients and "deferred" in 32.9%. Interrater reliability was very high (kappa = 0.97, 95% CI 0.91-1, p < 0.001). The sensitivity and specificity of the VADT to correctly decide on VA placement were 0.92 (0.8-0.98) and 1 (0.79-1). Using the VADT, no patient would have undergone unnecessary VA placement. In reality, 4.3% of patients had an unnecessary VA placed which required a subsequent removal.

CONCLUSIONS

These preliminary data support the continued study of this VADT to guide intraoperative decisions regarding VA placement in patients with renal tumors.

LEVEL OF EVIDENCE

III - Study of diagnostic test.

Relapsed Wilms' tumor in pediatric patients: challenges in low- to middle-income countries-a single-center experience

BACKGROUND

Wilms' tumor (WT) affects one in 10,000 children and accounts for 5% of all childhood cancers. Although the overall relapse rate for children with WT has decreased to less than 15 %, the overall survival for patients with recurrent disease remains poor at approximately 50 %. The aim of the study to evaluate the outcome of relapsed Wilms' tumor pediatric patients treated at the National Cancer Institute (NCI), Egypt, between January 2008 and December 2015.

RESULTS

One hundred thirty (130) patients diagnosed with WT during the study period, thirty (23%) patients had relapsed. The median follow up period was 22.3 months (range 3.6-140 months). The Overall Survival (OS) was 30.9% while the event-free survival (EFS) was 29.8% at a 5-year follow up period. Median time from diagnosis to relapse was 14.4 months. A second complete remission was attained in 18/30 patients (60%). The outcome of the 30 patients; 11 are alive and 19 had died. Three factors in our univariate analysis were prognostically significant for survival after relapse. The first was radiotherapy given after relapse (p = 0.012). The 5-year EFS and OS for the group that received radiotherapy were 41.9% versus 16.7% and 11.1% respectively for those that did not. The second was the state of lymph nodes among patients with local stage III (p = 0.004). Lastly, when risk stratification has been applied retrospectively on our study group, it proved to be statistically significant (p = 0.029).

CONCLUSION

Among relapsed pediatric WT, radiotherapy improved survival at the time of relapse and local stage III with positive lymph nodes had the worst survival among other stage III patients.

Factors affecting lymph node sampling patterns and the impact on survival of lymph node density in patients with Wilms tumor: a Surveillance, Epidemiology, and End Result (SEER) database review

BACKGROUND

Lymph node (LN) involvement is an important prognostic indicator for patients with Wilms tumor (WT), and there have been previous reports of utilizing LN density (LND = positive LN/LNs examined) as an advanced metric to risk-stratify patients with WT.

OBJECTIVE

The purpose of this study was to describe patient characteristics that affect LN yield and assess the effect of LND on the overall survival (OS) in patients with WT, with the expectation that patients with LNDs above a critical cut-point would demonstrate lower OS.

STUDY DESIGN

The Surveillance, Epidemiology, and End Result (SEER) database was queried for all patients diagnosed with unilateral WT from 2004 to 2015. Patient and disease characteristics were collected, and Poisson regression was used to identify characteristics correlated with LN yield. LND was calculated for LN-positive patients, and multivariable survival analysis was performed, including patient demographics and LND as variables.

RESULTS

1489 patients with unilateral WT were identified for analysis, 231 (15.51%) of whom were LN-positive. Median patient age at diagnosis was three years (IQR 1-5). On Poisson regression, the year of diagnosis, patient age, tumor size and laterality, and stage were found to impact LN yield. For patients with positive LNs, five-year OS of patients with LNDs above 0.4 was worse than those below 0.4 (76.1% vs 89.6%, p = 0.041). On multivariable analysis, tumor size and LND remained significant predictors of OS.

DISCUSSION

Administrative databases such as SEER provide an excellent resource for studying conditions where large patient numbers for analysis are difficult to obtain. Unfortunately, the SEER database is unable to account for every factor that could affect LN sampling patterns. Additionally, favorable vs unfavorable histology is not available in SEER, and SEER utilizes its own staging system, which makes comparison to Children's Oncology Group staging difficult. Despite these limitations, the findings of this study are similar to those previously published using administrative databases analyzing LN sampling patterns and the effect of LND on OS in WT.

CONCLUSIONS

Analysis of the SEER database confirms that there are several patient- and disease-specific factors that affect the number of LNs sampled during nephrectomy for WT, and that LND may be a predictor of OS. These findings highlight the need for standardization of LN sampling patterns for pediatric renal tumors and support the investigation of LND in future studies to further risk-stratify WT patients to tailor therapy intensity.

Evaluation of Nephron-Sparing Surgery as Potential Risk Factor for Relapse in Unilateral Wilms Tumor

BACKGROUND

The aim of the study was to assess the prognostic significance of nephron-sparing surgery (NSS) without tumor size limits as a risk factor for relapse in children with unilateral Wilms Tumor (WT).

METHODS

A 28-y retrospective single-center review was performed. Prognostic relevance of age, gender, stage, histology, nephrectomy (N), and NSS was analyzed.

RESULTS

Sixty-nine cases (42 females and 27 males) with WT, off-therapy from 21 to 325 mo after chemotherapy mainly based on the International Society of Pediatric Oncology trials, were treated at our institution. Five cases were excluded (three children with synchronous bilateral WT and two adults with unilateral WT). Of 64 children with unilateral WT, 51 underwent N and 13 NSS without tumor size limits. Indeed, two-thirds of children who underwent NSS presented with a tumor diameter >4 cm. Overall, nine patients (14%) had a relapse (male-to-female ratio = 1:8). Initial surgery was N in eight cases and NSS in another one. Relapse rates in N and NSS groups were 15.7% and 7.7% (P = nonsignificant), respectively; the relapse rates in N and NSS groups were 8.6% and 7.7% (P = nonsignificant) for stages I-II unilateral WT cohort, respectively. On univariate analysis, factors correlated with probability of relapse were unfavorable histology (P < 0.002) and stage III disease (P < 0.01).

CONCLUSIONS

In unilateral WT, NSS, whenever feasible, does not seem to increase the risk of recurrence. A multicenter prospective trial is required to carefully evaluate this risk.

Prognostic Factors and Nomograms to Predict Overall and Cancer-Specific Survival for Children with Wilms' Tumor

Objective

This study is aimed at constructing and verifying nomograms that forecast overall survival (OS) and cancer-specific survival (CSS) of children with Wilms' tumor (WT).

Patients and methods

Clinical information of 1613 WT patients who were under 18 years old between 1988 and 2010 was collected from the Surveillance, Epidemiology, and End Results (SEER) database. Using these data, we performed univariate as well as multivariate Cox's regression analyses to determine independent prognostic factors for WT. Then, nomograms to predict 3- and 5-year OS and CSS rates were constructed based on the identified prognostic factors. The nomograms were validated externally and internally. The nomograms' reliability was evaluated utilizing receiver operating characteristic (ROC) curves and concordance indices (C-indices).

Results

1613 WT patients under 18 were involved in the study and randomly divided into the training (n = 1210) and validation (n = 403) cohorts. Age at diagnosis, tumor laterality, tumor size, tumor stage, and use of surgery were determined as independent prognostic factors for OS and CSS in WT and were further applied to construct prognostic nomograms. The C-index and area under the receiver operating characteristic curve (AUC) revealed the great performance of our nomograms. Internal and external calibration plots also showed excellent agreement between actual survival and nomogram prediction.

Conclusion

Precise and convenient nomograms were developed for forecasting OS and CSS of children with WT. These nomograms were able to offer accurate and individualized prognosis and assisted clinicians in performing suitable therapy.

How many lymph nodes are enough? Assessing the adequacy of lymph node yield for staging in favorable histology wilms tumor

PURPOSE

Current investigational priorities in the treatment of favorable histology Wilms tumor (FHWT) center on accurate staging and risk-stratification. The extent of lymph node (LN) sampling has not been clearly defined; its importance cannot be overstated as it guides adjuvant therapy. The identification of a minimum LN yield to minimize the risk of harboring occult metastatic disease could help development of surgical guidelines. This study focuses on using the beta-binomial distribution to estimate the risk of occult metastatic disease in patients with FHWT.

MATERIALS & METHODS

The National Cancer Database was queried for patients with unilateral FHWT from 2004 to 2013. Data were used to characterize nodal positivity for patients who underwent surgery and had ≥1 positive LN and ≥2 LNs examined. The probability of missing a positive LN (i.e., false negative) for a given LN yield was calculated using an empirical estimation and the beta-binomial model. Patients were then stratified by tumor size.

RESULTS

422 patients met study criteria. To limit the chance of missing a positive LN to ≤10%, the empirical estimation and beta-binomial model estimated that 6 and 10 LNs needed to be sampled, respectively. Tumor size did not influence the result. Internal validation showed little variation to maintain a false negative rate ≤ 10%.

CONCLUSIONS

Using mathematical modeling, it appears that the desired LN yield in FHWT to reduce the risk of false-negative LN sampling to ≤10% is between 6 and 10. The current analysis represents an objective attempt to determine the desired surgical approach to LN sampling to accurately stage patients with FHWT.

LEVEL OF EVIDENCE

II.

Imaging of Wilms tumor: an update

Wilms tumor is the most common pediatric renal tumor, accounting for approximately 7% of all childhood cancers. Imaging plays an important role in the detection, staging, post-therapy evaluation and surveillance of Wilms tumor. Wilms tumor can be detected during surveillance of a known cancer predisposition or after a child presents with symptoms. In this manuscript we describe an evidence-based approach to the initial evaluation of Wilms tumor using current guidelines from the Children's Oncology Group (COG). We illustrate the COG staging system for pediatric renal tumors and highlight key imaging findings that are critical for surgical management. We also discuss the controversies regarding detection and significance of <5-mm pulmonary nodules at initial staging. And finally, we present some thoughts regarding surveillance of Wilms tumor, where overall survival has now approached 90%.

Evaluation of needle biopsy as a potential risk factor for local recurrence of Wilms tumour in the SIOP WT 2001 trial

RATIONALE

The impact of biopsying Wilms tumour (WT) at diagnosis on assigning the tumour stage and recommended treatment remains controversial. To address this important question, we analysed the potential association of all types of biopsy with local recurrence in patients treated in the SIOP WT 2001 trial, where needle biopsy was permitted without 'upstaging' the tumour to stage III. Only open biopsy required treatment as stage III.

METHODS

Among 2971 patients with unilateral WT (stages I-IV), 420 relapsed (139 local). Risk factors for recurrence were analysed by Cox proportional hazard methods.

RESULTS

Biopsy was performed in 969 of 2971 (33%) patients (64% cutting needle, 30% fine needle aspiration [FNA] and 6% open biopsy). Biopsied patients were older, with larger tumours and a greater proportion with high-risk histology. In multivariate analysis that included all factors associated with local recurrence in univariate analysis, only high-risk histology (hazard ratio [HR] = 2.32; 95% confidence interval [CI]: 1.58-3.42, p=<0.0001), age≥2 years (HR = 2.24; 95% CI: 1.22-4.09, p = 0.01) and preoperative tumour volume (HR = 1.07 per 100 ml; 95% CI: 1.02-1.12, p = 0.01) were significant. The HR for the association of local recurrence and event-free and overall survival with biopsy was not significant (HR = 1.4; 95% CI: 0.9-2.17, p = 0.13; HR = 1.1; 95% CI: 0.85-1.42, p = 0.46 and HR = 1.13; 95% CI: 0.79-1.62, p = 0.51, respectively). These results were not materially different whether FNA or open biopsy were included in the biopsy group or not.

CONCLUSIONS

This post hoc analysis provides some reassurance that needle biopsy is not an independent adverse factor for either local recurrence or survival after adjustment for all relevant risk factors. Needle biopsy should not be an automatic criterion to 'upstage' WT.

National Survey on the Management of Wilms Tumor

This study aims to investigate the management of Wilms tumor by the Egyptian pediatric surgical association (EPSA) consultants. After approval of the EPSA executive board, a questionnaire was distributed individually to all consultants attending the general assembly of EPSA 2017 annual congress. Of 88 consultants, responses were received from 61. Palpable abdominal mass was indicated by 72.13% of respondents as the commonest presenting symptom. Concerning the imaging requested, computed tomography was reported by 80.33%. Approximately 62.30% of respondents perform 1 to 3 cases annually. Regarding timing of surgery, upfront resection was the most frequently reported by 62.30%. A total of 77.05% perform lymph node sampling during surgeries. Nephron-sparing surgery was adopted by only 26.23%, whereas none of the respondents reported the use of minimally invasive surgery for management. Overall, 93.44% of surgeons ask for a visit every 3 months in the first year postoperatively. Upfront nephrectomy is the commonest procedure for Wilms tumor in the current practice of EPSA consultants, whereas there is consensus against minimally invasive surgery. Surgical guidelines for nephron-sparing surgery are still incomplete and need to be tabulated. This study urges for a nationwide retrospective analysis to establish a uniform protocol with international reference to be adopted in Egypt.

Update on Wilms tumor

This article reviews of the current evidence-based treatment standards for children with Wilms tumor. In this article, a summary of recently completed clinical trials by the Children's Oncology Group is provided, the current diagnostic evaluation and surgical standards are discussed, and the surgical impact on current risk stratification for patients with Wilms tumor is highlighted. LEVEL OF EVIDENCE: This is a review article of previously published and referenced LEVEL 1 studies, but also includes expert opinion LEVEL V, represented by the American Pediatric Surgical Association Cancer Committee.

Outcomes of non-anaplastic stage III and 'inoperable' Wilms tumour treated in the UKW3 trial

BACKGROUND AND PURPOSE

To describe the outcome of patients with stage III Wilms tumours (WT) treated in the UKW3 trial.

MATERIAL AND METHODS

Patients with a pathologically confirmed stage III non-anaplastic WT at nephrectomy (Group A) or with an 'inoperable' tumour at diagnosis managed by biopsy and pre-operative chemotherapy (Actinomycin D-Vincristine-Doxorubicin) but stage I or II at subsequent nephrectomy (Group B) were included.

RESULTS

The 4-year overall (OS)/event free survival (EFS) for Group A (n = 117) patients was 90%(95%CI:83-94)/81%(CI:73-87) and for Group B (n = 32) 94%(CI:77-98)/88%(CI:70-95). The 4-year OS/EFS of patients with pathological stage III WT according to whether they received flank/abdominal radiotherapy (95 patients) or not (37 patients, 22 from UKW3 pooled with 17 patients from UKW2) were 91%(CI:83-95)/82%(CI:73-89), and 84%(CI:67-92)/78%(CI:61-89), respectively. The 4-year OS/EFS for patients having one reason to be stage III versus two or three was 92%(CI:84-96)/83%(CI:73-90) and 85%(CI:70-93)/78%(CI:61-88), respectively.

CONCLUSION

Our findings question the inclusion of biopsy or pre-operative chemotherapy as sole criterion for assigning a tumour stage III. Selected patients with pathological stage III WT can survive without radiotherapy. Whilst cautious interpretation is needed due to the post hoc nature of these analyses, further biological studies may better characterise those who could benefit from reduced therapy.

Lymph node imaging of pediatric renal and suprarenal malignancies

Pediatric renal and suprarenal cancers are relatively rare malignancies, but are not without significant consequence to both the patient and caretakers. These tumors are often found incidentally and present as large abdominal masses. Standard of care management involves surgical excision of the mass, but contemporary treatment guidelines advocate for use of neoadjuvant or adjuvant chemotherapy for advanced stage disease, such as those cases with lymph node involvement (LNI). However, LNI detection is based primarily on surgical pathology and performing extended lymph node dissection can add significant morbidity to a surgical case. In this review, we focus on the use and performance of imaging modalities to detect LNI in Wilms’ tumor (WT), neuroblastoma, and pediatric renal cell carcinoma (RCC). We report on how imaging impacts management of these cases and the clinical implications of LNI. A literature search was conducted for studies published on imaging-based detection of LNI in pediatric renal and suprarenal cancers. Further review focused on surgical and medical management of those cases with suspected LNI. Current imaging protocols assisting in diagnosis and staging of pediatric renal and suprarenal cancers are generally limited to abdominal ultrasound and cross-sectional imaging, mainly computed tomography (CT). Recent research has investigated the role of more advance modalities, such as magnetic resonance imaging (MRI) and positron emission tomography (PET), in the management of these malignancies. Special consideration must be made for pediatric patients who are more vulnerable to ionizing radiation and have characteristic imaging features different from adult controls. Management of pediatric renal and suprarenal cancers is influenced by LNI, but the rarity of these conditions has limited the volume of clinical research regarding imaging-based staging. As such, standardized criteria for LNI on imaging are lacking. Nevertheless, advanced imaging modalities are being investigated and potentially represent more accurate and safer options.

A case report of infantile cystic nephroblastoma

BACKGROUND

Nephroblastoma (NB) is a malignant embryonal neoplasm derived from nephrogenic blastemal cells. NB usually forms a solid mass, but in extremely rare cases, it may show cystic changes.

CASE PRESENTATION

A six-month-old girl with persistent high fevers was found to have pyuria and bacteriuria. Ultrasonography revealed multilocular cysts in the right kidney. Right nephrectomy was performed with cyst wall rupture during surgery. An intraoperative rapid diagnosis, based on peritoneal fluid cytology, confirmed three components of blastemal, stromal, and epithelial cells. The blastemal cells were dyshesive, with scant to no cytoplasm and were the predominant cell type. The spindle-shaped stromal cells were arranged in fascicles. The epithelial cells demonstrated tubular structures. Macroscopically, the resected cystic tumor measured 80 mm in maximum diameter with a prominently thin cyst wall, but solid areas were also apparent. Histologically, the tumor was diagnosed as cystic NB (blastemal-predominant) displaying a triphasic pattern. Hyperchromatic nuclei and apoptotic bodies were found. The clinical stage classification of Japan Wilms Tumor Study group was 3. The patient was treated with chemotherapy and radiotherapy. Tumor recurrence and metastasis have not been observed in the 8 months since surgery.

CONCLUSION

This is an extremely rare case of infantile cystic NB. We diagnosed the NB cells that appeared in the peritoneal fluid by intraoperative rapid cytology. Cytological examination proved to be a very useful technique for determining the clinical stage of NB. Additionally, we propose that massive tumor degeneration and necrosis be considered as a pathogenic mechanism of cyst formation in NB.

Minimally Invasive Approaches to Pediatric Solid Tumors

Over the last decade, driven in part by the favorable adult experience and a crescendoing number of case series and retrospective reports in the pediatric surgical literature, minimally invasive surgical (MIS) approaches are increasingly used as adjunctive or definitive surgical treatments for an ever-expanding list of pediatric tumors. Although most current treatment protocols lack surgical guidelines regarding the use of MIS, this growing body of MIS literature provides a framework for the development of multicenter trial groups, prospective registries, and further centralization of subspecialist services. This article highlights the current available data on MIS approaches to a variety of pediatric malignancies.

Development of a postoperative care pathway for children with renal tumors

PURPOSE

To identify the factors associated with a shorter postoperative stay, as an initial step to develop a care pathway for children undergoing extirpative kidney surgery.

STUDY DESIGN

This study retrospectively reviewed patients managed with upfront open radical nephrectomy for renal tumors between 2005 and 2016 at a pediatric tertiary care facility. Univariate and multivariate logistic regression were performed to identify factors associated with early discharge (by postoperative day 4).

RESULTS

A total of 84 patients met inclusion criteria. Median age was 28.1 months (range 1.8-193.1). Thirty-four (40.5%) patients had a nasogastric tube postoperatively. The patients were advanced to a clear liquid diet on a median postoperative day 2 (range 0-7) and regular diet on a median postoperative day 3 (range 1-8). Median time from surgery to discharge was 5 days (range 2-12), with 38 (45.2%) discharged early. Univariate and multivariate logistic regression analyses showed that earlier resumption of regular diet (OR 0.523, P = 0.028) was positively associated with early discharge. Other analyzed factors were not significant (see Table).

DISCUSSION

Timely initiation of adjuvant therapy is a specific requirement of Children's Oncology Group (COG) protocols. Chemotherapy and radiation therapy are ideally initiated simultaneously, as early as possible, within 2 weeks of surgery. Thus, factors that can facilitate early discharge from the hospital can maximize protocol adherence with respect to timing of adjuvant therapy initiation and optimize patient outcome. This study shed light on several postoperative factors and how these relate to postoperative stay and recovery. Specifically, tumor size, pre-operative bowel preparation, extent of lymph node sampling, stage, operative time, estimated blood loss, surgical service, postoperative nasogastric tube use, transfusion, and chemotherapy prior to discharge were not associated with discharge timing. Early re-feeding was associated with early discharge. Thus, it seems reasonable that, when developing a postoperative care pathway for these patients, these factors be considered and specifically encourage early re-feeding. In pediatrics, data on early recovery after surgery protocols are limited, and high-quality studies are unavailable. Within pediatric urology, early recovery after surgery protocols in children undergoing major urologic reconstruction have been shown to reduce hospital stay and can decrease complication rates. It seems reasonable that a similar pathway can be applied to children undergoing radical nephrectomy for suspected malignancy.

CONCLUSIONS

For children with renal tumors who underwent radical nephrectomy, early re-feeding was associated with a shorter time to discharge. Use of bowel preparation and nasogastric tube did not appear to shorten time to discharge. These data are important for developing postoperative care pathways for these patients.

Patterns of lymph node sampling and the impact of lymph node density in favorable histology Wilms tumor: An analysis of the national cancer database

INTRODUCTION

There is controversy about the role of lymph node (LN) sampling or dissection in the management of favorable histology (FH) Wilms tumor (WT), specifically how it performed and how it may impact survival.

OBJECTIVE

The objective of this study was to analyze factors affecting LN sampling patterns and the impact of LN yield and density (number of positive LNs/LNs examined) on overall survival (OS) in patients with advanced-stage favorable histology Wilms tumor (FHWT).

METHODS

The National Cancer Database (NCDB) was queried for patients with FHWT during 2004-2013. Demographic, clinical and OS data were abstracted for those who underwent surgical resection. Poisson regression was performed to analyze how factors influenced LN yield. Patients with positive LNs had LN density calculated and were further analyzed.

RESULTS

A total of 2340 patients met criteria, with a median age at diagnosis of 3 years (range 0-78 years). The median number of LNs examined was three (range 0-87). Lymph node yield was affected by age, race, insurance, tumor size, laterality, advanced stage, LN positivity, and institutional volume. A total of 390 (16.6%) patients had LN-positive disease. Median LN density for these LN-positive patients was 0.38 (range 0.02-1) (Summary Figure). Estimated 5-year OS was significantly improved for those with LN density ≤0.38 vs. >0.38 (94% vs. 84.6%, P = 0.012). In this population, on multivariate analysis, age and LN density were significant predictors of OS.

DISCUSSION

It is difficult to compile large numbers of cases in rare diseases like WT, and fortunately a large administrative database such as the NCDB can serve as a great resource. However, administrative data come with inherent limitations such as missing data and inability to account for a variety of factors that may influence LN yield and/or OS (specimen designation, pathologist experience, surgeon experience/volume, institutional Children's Oncology Group (COG) association, etc.). In this specific disease, the American Joint Committee on Cancer staging (captured by the NCDB) is different than the COG WT staging system that is used clinically, and the NCDB does not capture oncologic outcomes beyond OS.

CONCLUSIONS

In a review of the NCDB, various factors associated with LN yield and observed LN density were identified to be significantly associated with OS in patients with LN-positive FHWT. This reinforces the need for adequate LN sampling at the time of WT surgery, to maximize surgical disease control. It was proposed that LN density as a metric may allow for improved risk-stratification, and possibly allow for therapeutic reduction in a sub-set of patients with low LN density.

Feasibility of laparoscopic tumour nephrectomy in children

AIMS

The laparoscopic approach to tumour nephrectomy in children is controversial. We therefore reviewed our institution's cases of tumour nephrectomy (laparoscopic, open, and converted) to better understand which is suitable for this approach, what factors prevent it, and whether one can excise tumours greater than the CCLG recommendation of 300 ml.

METHODS

All tumour nephrectomies performed between 2002 and 2016 were identified using our surgical database. Further data were gathered from radiology and pathology databases. Those with nonrenal tumours or having a partial nephrectomy were excluded. Tumour maximum diameters, volumes, and ratios to contralateral kidneys were calculated. A Mann-Whitney U was used to compare the groups.

RESULTS

Forty-three cases were included. Fifteen procedures were completed laparoscopically (35%), and a further 3 converted. The median age at surgery was 2.5 years (range 0-10) in the laparoscopic group and 2 years (range 0-15) in the open group. There was a significant difference (P < 0.05) between the laparoscopic and open groups for: median maximum diameter (10cm vs 12.25cm), median volume (155 ml vs 459 ml), maximum diameter ratio (1.22 vs 1.75), and volume ratio (3.8 vs 11.2).

CONCLUSION

Tumours in the laparoscopic group were significantly smaller, but it was possible to excise tumours more than 300 ml. Difficulties in excision related to tumour size relative to the abdomen. Therefore, a ratio of tumour to contralateral kidney may be a better guide to safe excision than an overall volume cutoff. From our series, the laparoscopic approach is likely to be achievable if the volume ratio is ≤ 8.1.

LEVEL OF EVIDENCE

Level 3.