Relapse of Wilms' tumour and detection methods: a retrospective analysis of the 2001 Renal Tumour Study Group-International Society of Paediatric Oncology Wilms' tumour protocol database

Real-world implementation of North American and SIOP strategies for the treatment of Wilms tumor in Uruguay

Wilms tumor has been selected as an index tumor by the WHO Global Initiative for Childhood Cancer with the aim to improve cure rates worldwide. Nevertheless, there is a scarcity of published data on outcomes beyond those of the major cooperative groups. Therefore, we conducted a retrospective analysis including all patients with Wilms tumor treated at our referral center in Uruguay between 1995 and 2020. Treatment consisted of North American (NA) strategies in 23 cases (1995-2004), followed by the SIOP strategy in 35 cases thereafter. Staging included: I-II = 28, III = 7, IV = 14, and V = 9. There were no major surgical or medical complications; however, a delay in the administration of local radiotherapy was observed (median of 21 days after surgery). There were no cases of toxicity- or surgery-related deaths or treatment abandonment. Five-year probability of overall survival was 0.72 and 0.92 for the NA and SIOP groups, respectively. We conclude that outcomes were better for the SIOP strategy with no unexpected toxicities and high treatment compliance in both strategies. Timely implementation of radiotherapy was challenging.

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.

The association of miR-204 and mir-483 5p expression with clinicopathological features of Wilms tumor: Could this provide foresight?

BACKGROUND

Wilms tumor is the most common cancer of the kidney that occurs during childhood, and histologically, it mimics renal embryogenesis. With the development and improvement of up-to-date treatment protocols, the survival rates of Wilms tumor have increased. However, metastases or local relapses are still observed in 15% of patients. The search for reliable biomarkers to identify at-risk patients is ongoing to predict the variability in treatment success. Currently, the evaluation of clinical, histopathological and genetic features are common diagnostic methods; however, epigenetic features can be examined with microRNA expression analyses and might allow us to comment on the behavior of the tumor and treatment response.

METHODS

In this study, we aimed to evaluate the relationship between microRNA-204 and microRNA-483-5p expression with clinicopathological data and the effect on Wilms tumor survival. For this purpose, the expression levels of RNU6B, microRNA-204 and microRNA-483-5p were evaluated in tumor and normal tissue by qreal time-polymerase chain reaction. We also investigated the relationship between microRNA expression levels with the clinicopathological and histological features of Wilms tumor.

RESULTS AND CONCLUSION

The results of our study indicate that the relative expression levels of microRNA-204 in Wilms tumor tissues were significantly lower than that in adjacent normal tissues. By contrast, tumor tissue had a higher microRNA-483-5p expression than the corresponding normal tissues. A statistically significant difference between microRNA-204 expression level with age and the presence of anaplasia was observed. The upregulation of microRNA-483-5p was found to have a significant correlation with patients after preoperative chemotherapy and complete tumor necrosis. Taken together, our data suggest that microRNA-204 could play a critical role as a tumor suppressor, whereas microRNA-483-5p acts as an oncogene in Wilms tumor progression. More importantly, microRNA-204 might be a novel predictive biomarker for anaplastic histology and could be useful for developing therapeutic interventions targeting this marker.

Biomarkers for patients with Wilms tumor: a review

Wilms tumor, originating from aberrant fetal nephrogenesis, is the most common renal malignancy in childhood. The overall survival of children is approximately 90%. Although existing risk-stratification systems are helpful in identifying patients with poor prognosis, the recurrence rate of Wilms tumors remains as high as 15%. To resolve this clinical problem, diverse studies on the occurrence and progression of the disease have been conducted, and the results are encouraging. A series of molecular biomarkers have been identified with further studies on the mechanism of tumorigenesis. Some of these show prognostic value and have been introduced into clinical practice. Identification of these biomarkers can supplement the existing risk-stratification systems. In the future, more biomarkers will be discovered, and more studies are required to validate their roles in improving the detection rate of occurrence or recurrence of Wilms tumor and to enhance clinical outcomes.

Update on the Role of Imaging in Staging of Common Pediatric Abdominal Tumors

Neuroblastoma, Wilms tumor, and hepatoblastoma are the most common pediatric abdominal malignancies. Management of these diseases is a multidisciplinary process that continues to evolve based on the results of international collaborative trials and advances in understanding of tumor biology. Each of these tumors has unique characteristics and behavior which are reflected in their respective staging systems. It is important for clinicians involved in the care of children with abdominal malignancies to be familiar with current staging guidelines and imaging recommendations. This article reviews the current role of imaging in the management of these common pediatric abdominal malignancies, with emphasis on initial staging.

Imaging of pediatric renal tumors: A COG Diagnostic Imaging Committee/SPR Oncology Committee White Paper focused on Wilms tumor and nephrogenic rests

Malignant renal tumors account for approximately 6% of pediatric malignancies, with Wilms tumor (WT) representing approximately 90% of pediatric renal tumors. This paper provides consensus-based imaging guidelines for the initial evaluation of a child with suspected WT and follow-up during and after therapy co-developed by the Children's Oncology Group (COG) Diagnostic Imaging and Society for Pediatric Radiology (SPR) oncology committees. The guidelines for Wilms Tumor Imaging in the Society of International Pediatric Oncology (SIOP) are briefly discussed to highlight some of the differences in imaging approach.

Should we reduce routine surveillance imaging in pediatric germ cell tumors?

This paper retrospectively investigated the site and the detection method of relapses in children and adolescents with malignant germ cell tumors enrolled in the TCGM-AIEOP-2004 Study and subsequently developed a relapse, in order to evaluate a possible reduction in radiological exposure during follow-up. Including all malignant cases, serum tumor markers identified a relapse in more than 70% and, according to the selection criteria published by Children Oncology Group in 2018, in more than 90% of cases. These results confirm the importance of serum tumor markers as a relapse detection method, with possible reduction of radiology exams in specific subgroups.

Outcomes according to treatment using an established protocol in patients with bilateral Wilms' tumor: A national Canadian population-based study

BACKGROUND

Bilateral Wilms tumor (BWT) is a rare entity. The goal of this study is to report outcomes (overall and event-free survival, OS/EFS) of BWT in a large cohort representative of the Canadian population since 2000. We focused on the occurrence of late events (relapse or death beyond 18 months), as well as outcomes of patients treated following the only protocol specifically designed for BWT to date, AREN0534, compared to patients treated following other therapeutic schemes.

METHODS

Data was obtained for patients diagnosed with BWT between 2001 and 2018 from the Cancer in Young People in Canada (CYP-C) database. Demographics, treatment protocols, and dates for events were collected. Specifically, we examined outcomes of patients treated according to the Children's Oncology Group (COG) protocol AREN0534 since 2009. Survival analysis was performed.

RESULTS

57/816 (7%) of patients with Wilms tumor had BWT during the study period. Median age at diagnosis was 2.74 years (IQR 1.37-4.48) and 35 (64%) were female; 8/57 (15%) had metastatic disease. After a median follow-up of 4.8 years (IQR 2.8-5.7 years, range 0.2-18 years), OS and EFS were 86% (CI 73-93%) and 80% (CI 66-89%), respectively. Less than 5 events were recorded after 18 months from diagnosis. Since 2009, patients treated according to the AREN0534 protocol had a statistically significant higher OS compared to patients treated with other protocols.

CONCLUSIONS

In this large Canadian cohort of patients with BWT, OS and EFS compared favorably to the published literature. Late events were rare. Patients treated according to a disease-specific protocol (AREN0534) had improved overall survival.

TYPE OF STUDY

Original article.

LEVEL OF EVIDENCE

Level IV.

Relapsing pediatric non-rhabdomyosarcoma soft tissue sarcomas: The impact of routine imaging surveillance on early detection and post-relapse survival

PURPOSE

The chances of patients with relapsing pediatric non-rhabdomyosarcoma soft tissue sarcomas (NRSTS) being cured are limited. This retrospective single-institutional study examines the potential role of routine surveillance imaging for detecting recurrent tumor, and its impact on post-relapse survival.

METHODS

The analysis concerned 86 patients < 21 years old with relapsing NRSTS treated from 1985 to 2020. Clinical findings, treatment modalities and survival were analyzed, comparing patients whose relapse was first suspected from symptoms (symptomatic group) with those whose relapse was detected by radiological surveillance (imaging group).

RESULTS

Tumor relapses were identified from clinical symptoms in 49 cases and on routine imaging in 37. Time to relapse was similar in the two groups. Routine imaging detected 6/32 local relapses and 31/48 distant relapses (and 79% of the cases of lung metastases). Overall survival (OS) at 5 years was 34.3% for the symptomatic group, and 24.0% for the imaging group (p-value 0.270). In patients with lung metastases at relapse, the 5-year OS was statistically better for the imaging group, that is, 25.8% versus 0% for the symptomatic group (p-value 0.044).

CONCLUSION

This is the first study to explore the role of surveillance imaging in pediatric NRSTS. Judging from our findings, the value of routine scanning of primary sites seems limited, while radiological surveillance may help to detect lung metastases, improving survival for this patient category. The potentially negative effects of periodic radiological exams should be considered in deciding the optimal follow-up for patients off therapy.

Role of Ultrasonography in the Diagnosis of Wilms’ Tumour

Background. Wilms’ tumour or nephroblastoma is the most common renal malignancy encountered in the paediatric population. Imaging findings are of great importance to the surgeon, the oncologist and the radiologist in the diagnosis and the staging and surveillance of this tumour. Material and Methods. This study was carried out as a 10-year retrospective study of patients who were diagnosed with Wilms’ tumour. Results. The study included 12 boys and 11 girls. Ultrasound and computed tomography were performed in all cases. Ultrasonography was found to be superior to the CT examination when approximating the antero-posterior and transverse diameters; the computer-tomographic examination is cited as superior for estimating the invasion of nephroblastomas. Conclusions: Ultrasound has been shown to be effective in detecting the rupture of the renal capsule, tumour calcifications and invasion of the renal vein, pelvis and ureter. However, ultrasound cannot replace CT in the detection of lymphadenopathy and the invasion of adjacent organs.

Is Detection of Relapse by Surveillance Imaging Associated With Longer Survival in Patients With Rhabdomyosarcoma?

BACKGROUND

We investigated whether surveillance imaging had an impact on post-relapse survival in patients with rhabdomyosarcoma (RMS). We hypothesized that relapse detected by imaging (group IM) would be associated with longer survival compared with relapse detected with a clinical sign or symptom (group SS).

MATERIALS AND METHODS

We performed an observational multi-institutional study in 127 patients with relapsed RMS comparing overall survival (OS) after relapse using Kaplan-Meier and Cox proportional hazards analyses.

RESULTS

Relapse was detected in 60 (47%) group IM and 67 (53%) SS patients. Median follow-up in survivors was 4 years (range 1.0 to 16.7 y). Four-year OS rates were similar between group IM (28%, 95% confidence interval [CI]: 14%-40%) and SS (21%, 95% CI: 11%-31%) ( P =0.14). In multivariable analyses accounting for institution, age at diagnosis, time to relapse, risk group at diagnosis, and primary site, not receiving chemotherapy (hazard ratio [HR]: 6.8, 95% CI: 2.8-16.6), radiation (HR: 3, 95% CI: 1.7-5.3), or surgery (HR: 2.8, 95% CI: 1.6-4.8) after relapse were independently associated with poor OS.

CONCLUSION

These results on whether surveillance imaging provides survival benefit in patients with relapsed RMS are inconclusive. Larger studies are needed to justify current surveillance recommendations. Chemotherapy, radiotherapy and surgery to treat recurrence prolong OS.

The Regulatory Network and Role of the circRNA-miRNA-mRNA ceRNA Network in the Progression and the Immune Response of Wilms Tumor Based on RNA-Seq

Circular RNA (circRNA), which is a newly discovered non-coding RNA, has been documented to play important roles in miRNA sponges, and the dysregulation of which is involved in cancer development. However, circRNA expression profiles and their role in initiation and progression of Wilms tumor (WT) remain largely unclear at present. Here, we used paired WT samples and high-throughput RNA sequencing to identify differentially expressed circRNAs (DE-circRs) and mRNAs (DE-mRs). A total of 314 DE-circRs and 1612 DE-mRs were identified. The expression of a subset of differentially expressed genes was validated by qRT–PCR. A complete circRNA-miRNA-mRNA network was then constructed based on the common miRNA targets of DE-circRs and DE-mRs identified by miRanda prediction tool. The Gene set enrichment analysis (GSEA) indicated that several signaling pathways involving targeted DE-mRs within the ceRNA network were associated with cell cycle and immune response, which implies their participation in WT development to some extent. Subsequently, these targeted DE-mRs were subjected to implement PPI analysis and to identify 10 hub genes. Four hub genes were closely related to the survival of WT patients. We then filtered prognosis-related hub genes by Cox regression and least absolute shrinkage and selection operator (LASSO) regression analysis to construct a prognosis-related risk score system based on a three-gene signature, which showed good discrimination and predictive ability for WT patient survival. Additionally, we analyzed the mutational landscape of these genes and the associations between their expression levels and those of immune checkpoint molecules and further demonstrated their potential impact on the efficacy of immunotherapy. qRT–PCR and western blotting (WB) analysis were used to validate key differentially expressed molecules at the RNA and protein levels, respectively. Besides these, we selected a key circRNA, circEYA1, for function validation. Overall, the current study presents the full-scale expression profiles of circRNAs and the circRNA-related ceRNA network in WT for the first time, deepening our understanding of the roles and downstream regulatory mechanisms of circRNAs in WT development and progression. We further constructed a useful immune-related prognostic signature, which could improve clinical outcome prediction and guide individualized treatment.

Outcome of SIOP patients with low- or intermediate-risk Wilms tumour relapsing after initial vincristine and actinomycin-D therapy only - the SIOP 93-01 and 2001 protocols

PURPOSE

Society of International Pediatric Oncology - Renal Tumor Study Group (SIOP-RTSG) treatment recommendations for relapsed Wilms tumour (WT) are stratified by the intensity of first-line treatment. To explore the evidence for the treatment of patients relapsing after vincristine and actinomycin-D (VA) treatment for primary WT, we retrospectively evaluated rescue treatment and survival of this patient group.

PATIENTS AND METHODS

We included 109 patients with relapse after VA therapy (no radiotherapy) for stage I-II primary low- or intermediate-risk WT from the SIOP 93-01 and SIOP 2001 studies. Univariate Cox regression analysis was performed to study the effect of relapse treatment intensity on event-free survival (EFS) and overall survival (OS). Relapse treatment intensity was classified into vincristine, actinomycin-D, and either doxorubicin or epirubicin (VAD), and more intensive therapies (ifosfamide/carboplatin/etoposide [ICE]/≥ 4 drugs/high-dose chemotherapy with haematopoietic stem cell transplantation [HD HSCT]).

RESULTS

Relapse treatment regimens included either VAD, or cyclophosphamide/carboplatin/etoposide/doxorubicin (CyCED), or ICE backbones. Radiotherapy was administered in 62 patients and HD HSCT in 15 patients. Overall, 5-year EFS and OS after relapse were 72.3% (95% confidence interval [CI]: 64.0-81.6%) and 79.3% (95% CI: 71.5-88.0%), respectively. Patients treated with VAD did not fare worse when compared with patients treated with more intensive therapies (hazard ratio EFS: 0.611 [95% CI: 0.228-1.638] [p-value = 0.327] and hazard ratio OS: 0.438 [95% CI: 0.126-1.700] [p-value = 0.193]).

CONCLUSION

Patients with relapsed WT after initial VA-only treatment showed no inferior EFS and OS when treated with VAD regimens compared with more intensive rescue regimens. A subset of patients relapsing after VA may benefit from less intensive rescue treatment than ICE/CyCED-based regimens and deserve to be pinpointed by identifying additional (molecular) prognostic factors in future studies.

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.

Fasting Intervention for Children With Unilateral Renal Tumors to Reduce Toxicity

Childhood renal tumors account for around 6% of all childhood cancers and 90% of these cases are Wilms tumor. In Europe, the SIOP-RTSG approach is considered standard of care and has resulted in five-year survival rates of over 90%. Efforts to decrease toxicity are now being pursued. Short-term fasting (STF), a short but strong reduction in calorie-intake, is associated with improved fitness, enhanced coping with acute physical stress and a lower risk of age-associated diseases. STF temporarily reduces growth to boost resilience, maintenance, and defense-mechanisms, by which toxic side-effects of (oxidative) damage and inflammation are largely prevented. Renal surgery for Wilms tumor carries a risk of acute kidney injury (AKI) and pediatric patients that had an episode of AKI are at increased risk for developing chronic renal disease. STF could mitigate surgery-induced stress and could further improve outcomes. We aim to investigate the effect of STF on renal function recovery after renal tumor surgery by conducting a single-center, prospective, randomized, non-blinded, intervention study. Children diagnosed with a unilateral renal tumor and opting for curative treatment are eligible for inclusion. The main study objective is to investigate the potential decrease in occurrence of AKI due to STF. Secondary objectives include renal function recovery, child's wellbeing, physical functioning, and feasibility of and adherence to STF in children with cancer.

A 10-year study of the outcome of wilms' tumor in central India and identifying practice gaps

Introduction:

Despite remarkable improvement in Wilms' tumor (WT) survival in Western world, sub-optimal outcome in resource-constrained settings is influenced by late presentation, larger size, and poor access to treatment. This prompted us to study the outcome at a tertiary care center and to identify the global and local practice gaps.

Materials and Methods:

A retrospective, observational study of WT was conducted from October 2009 to September 2019 at a tertiary care setting. Following the National Wilms' Tumor Study Group protocol, an upfront nephrectomy (unilateral resectable tumors) and preoperative chemotherapy (large/unresectable Stage I–III) were followed. The records were reviewed for demographics, stage, preoperative chemotherapy, predictive factors, and outcome. Survival curves were plotted by the Kaplan–Meier method, and analysis was performed using the SPSS software version 16.

Results:

One hundred and fifty-six children were included, median age was 4.1 years, with a male predominance. The most common stages of the presentation were II (40.4%) and III (34.6%). An upfront surgery was done in 27.6%, while remaining received preoperative chemotherapy. The median follow-up was 22 months, and the events included relapse in 46 (29.48%) and death in 54 (34.61%). The mean survival time was 45.7 (95% confidence interval [CI], 41.08–50.30). The 2-year overall survival was 65.38% (95% CI, 59–73), and the 2-year event-free survival was 36% (95% CI, 32–41). On comparison of the impact of preoperative chemotherapy, the survival estimates in Stages I–III and relapse rate were statistically similar, tumor size reduced significantly, and tumor spill was significantly lower (P < 0.05).

Conclusion:

WT is associated with late presentation, sub-optimal survival, and higher relapse in our setting associated with practice gaps related to the management including practice violations.

Roles of hydroxyacyl-CoA dehydrogenase trifunctional multienzyme complex subunit alpha, a lipid metabolism enzyme, in Wilms tumor patients

Objectives

Wilms tumor is a common pediatric malignant tumor that accounts for approximately 95% of kidney tumors in children. The role of lipid metabolism in tumors has attracted increased attention in recent years. We examined the role of hydroxyacyl-CoA dehydrogenase trifunctional multienzyme complex subunit alpha (HADHA), a lipid metabolism enzyme, in the pathogenesis of Wilms tumor.

Materials and Methods

In a previous study, we screened Wilms tumors and adjacent normal tissues for differentially expressed proteins by mass spectrometry and verified the results by western blot analysis. The Oncomine database and quantitative reverse transcription-polymerase chain reaction were used to verify the expression of HADHA at the genetic level. Immunohistochemistry and immunofluorescence were also used to validate the differential expression of the HADHA protein. The relationship between histopathological typing, clinical pathology, and HADHA expression was analyzed in 65 paraffin-embedded specimens from pediatric Wilms tumor patients. Kaplan-Meier survival curves were used to analyze the relationship between the expression of HADHA and patient prognosis.

Results

HADHA was expressed at low levels in Wilms tumor tissue compared with the corresponding normal tissue. The expression of HADHA was closely associated with histopathological typing (P = 0.030). The prognostic analysis of 65 children with Wilms tumor showed that high expression of HADHA was closely associated with poor prognosis (P = 0.046).

Conclusions

HADHA expression is downregulated in Wilms tumor tissues, but high expression in tumor tissues is associated with clinical stage and the prognosis of children with this tumor.

Novel Circulating Hypermethylated RASSF1A ddPCR for Liquid Biopsies in Patients With Pediatric Solid Tumors

Liquid biopsies can be used to investigate tumor-derived DNA, circulating in the cell-free DNA (cfDNA) pool in blood. We aimed to develop a droplet digital polymerase chain reaction (ddPCR) assay detecting hypermethylation of tumor suppressor gene RASSF1A as a simple standard test to detect various pediatric tumor types in small volume blood samples and to evaluate this test for monitoring treatment response of patients with high-risk neuroblastoma.

The circulating tumor marker hypermethylated RASSF1A can be detected in the plasma of pediatric patients with solid tumors

Wilms tumour

Wilms tumour (WT) is a childhood embryonal tumour that is paradigmatic of the intersection between disrupted organogenesis and tumorigenesis. Many WT genes play a critical (non-redundant) role in early nephrogenesis. Improving patient outcomes requires advances in understanding and targeting of the multiple genes and cellular control pathways now identified as active in WT development. Decades of clinical and basic research have helped to gradually optimize clinical care. Curative therapy is achievable in 90% of affected children, even those with disseminated disease, yet survival disparities within and between countries exist and deserve commitment to change. Updated epidemiological studies have also provided novel insights into global incidence variations. Introduction of biology-driven approaches to risk stratification and new drug development has been slower in WT than in other childhood tumours. Current prognostic classification for children with WT is grounded in clinical and pathological findings and in dedicated protocols on molecular alterations. Treatment includes conventional cytotoxic chemotherapy and surgery, and radiation therapy in some cases. Advanced imaging to capture tumour composition, optimizing irradiation techniques to reduce target volumes, and evaluation of newer surgical procedures are key areas for future research.

Analysis of the mutational status of SIX1/2 and microRNA processing genes in paired primary and relapsed Wilms tumors and association with relapse

Whereas 90% of patients with Wilms tumor (WT) reach cure, approximately half of patients developing a recurrent tumor die of the disease. Therefore, to disclose events leading to recurrence represents a clinical need. To study paired primary/recurrent tumor samples, being aware of the intra-tumoral heterogeneity, might help finding these answers. We previously suggested that mutations in SIX1 and DROSHA underlie WT recurrence. With the aim to better investigate this scenario, we collected 19 paired primary/recurrent tumors and 10 primary tumors from relapsing patients and searched for mutations in the SIX1/2 genes and microRNA processing genes (miRNAPGs). We found SIX1 mutation in one case, miRNAPGs mutations in seven cases, and the co-occurrence of SIX1 and miRNAPG mutations in one case. We could observe that, whereas in primary tumors the mutations could be heterogeneously present, in all cases they were positively selected and homogeneously present in the recurrent disease, as also indicated by a "moderate" and "almost perfect" agreement (according to the Landis and Koch classification criteria) between paired samples. Analysis of SIX1/2 genes and miRNAPGs in 50 non-relapsing WTs disclosed SIX2 mutation in one case and miRNAPGs mutations in seven. A borderline statistically significant association was observed between miRNAPGs mutations and the occurrence of relapse (p value: 0.05). These data suggest that SIX1 and miRNAPGs mutations may provide an advantage during tumor progression to recurrence and can represent oncogenic drivers in WT development.

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.

Genomes for Kids: The scope of pathogenic mutations in pediatric cancer revealed by comprehensive DNA and RNA sequencing

Genomic studies of pediatric cancer have primarily focused on specific tumor types or high-risk disease. Here, we used a three-platform sequencing approach, including whole genome (WGS), exome, and RNA sequencing, to examine tumor and germline genomes from 309 prospectively identified children with newly diagnosed (85%) or relapsed/refractory (15%) cancers, unselected for tumor type. Eighty-six percent of patients harbored diagnostic (53%), prognostic (57%), therapeutically-relevant (25%), and/or cancer predisposing (18%) variants. Inclusion of WGS enabled detection of activating gene fusions and enhancer hijacks (36% and 8% of tumors, respectively), small intragenic deletions (15% of tumors) and mutational signatures revealing of pathogenic variant effects. Evaluation of paired tumor-normal data revealed relevance to tumor development for 55% of pathogenic germline variants. This study demonstrates the power of a three-platform approach that incorporates WGS to interrogate and interpret the full range of genomic variants across newly diagnosed as well as relapsed/refractory pediatric cancers.

Expression of TCF3 in Wilms' tumor and its regulatory role in kidney tumor cell viability, migration and apoptosis in vitro

Wilms' tumor (WT) is a major type of kidney cancer in children; however, the therapeutic measures for control of tumor metastasis, recurrence and death for this type of cancer remain unsatisfactory. The present study aimed to verify the expression of T-cell factor 3 (TCF3) in WT, and to explore its role in regulating the viability, migration and apoptosis of kidney tumor cells. Tumor tissues were collected from 10 patients with WT, and adjacent tissues were collected as normal controls. The expression levels of TCF3 were detected in WT tissues and adjacent tissues by reverse transcription-quantitative PCR (RT-qPCR), western blotting and immunohistochemistry. In addition, TCF3 expression was silenced in G401 kidney tumor cells via small interfering RNA transfection. Cell viability, cell cycle progression and cell apoptosis were assessed using the MTT assay and flow cytometry; the migration and invasion of kidney tumor cells were examined using Transwell and wound-healing assays; and the expression levels of Wnt signaling pathway-related genes (Wnt1, β-catenin and c-myc) were detected by RT-qPCR and western blotting. The results revealed that the expression levels of TCF3 were high in WT tissues from patients. Silencing TCF3 expression in G401 kidney tumor cells in vitro significantly inhibited cell viability and migration, and promoted cell apoptosis. Moreover, silencing TCF3 expression in G401 cells inhibited the expression levels of Wnt signaling pathway-related genes. Overall, these data indicated that TCF3 may be involved in WT development through regulation of Wnt signaling pathways. The findings of the present study provide a novel potential marker for the treatment and prognostic evaluation of WT.

[Imaging of renal tumors in children]

CLINICAL/METHODOLOGICAL ISSUE

Renal tumors in children are treated according to the guidelines of the Renal Tumor Study Group of the International Society of Pediatric Oncology (SIOP-RTSG). Nephroblastoma is the most frequent renal tumor in children.

STANDARD RADIOLOGICAL METHODS

After sonography, magnetic resonance imaging (MRI) is the preferred imaging modality. The task of imaging includes differential diagnosis with the help of morphological and epidemiological criteria. Thorax computed tomography (CT) is introduced for initial staging.

METHODOLOGICAL INNOVATIONS

Current studies of diffusion-weighted imaging (DWI)-MRI with analysis of the apparent diffusion coefficient (ADC) histogram indicate the potential to differentiate blastemal or anaplastic high-risk histology nephroblatoma subtypes. Imaging criteria for nephron-sparing surgery are defined and allow an individual therapy option in unilateral and especially in bilateral renal nephroblastoma.

PERFORMANCE

In addition to nephroblastoma, the differential diagnosis includes congenital mesoblastic nephroma, malignant rhabdoid tumor of the kidney, clear cell sarcoma and renal cell carcinoma. The diagnosis of nephrogenic rests and nephroblastomatosis is challenging.

ACHIEVEMENTS

Diagnostic standardization improves diagnosis and therapy of renal childhood tumors, and new prognostic markers may be introduced in the near future.

Relapsed Wilms' Tumor Presenting as Metastasis to the Zygoma

Wilms’ tumor accounts for the majority of renal tumors in children. Rarely, Wilms’ tumor may metastasize to the bone. We present a case of a 15-month-old female who presented with severe abdominal distension and signs of cachexia. Abdominal ultrasonography and radiography of the abdomen both demonstrated a large abdominal mass. Follow-up computed tomography of the abdomen revealed a heterogeneous intra-abdominal mass arising from the left kidney which was surrounded by a thin rim of renal parenchyma. Biopsy of the mass revealed findings consistent with Wilms’ tumor. The patient was 14 months status-post nephrectomy and chemoradiation but returned to the clinic with left facial swelling. Magnetic resonance imaging of the face demonstrated a multilobulated, heterogeneously enhancing solitary mass lesion in the left temple centered in the left zygoma with signs of bone breakdown. Despite its rarity, metastatic Wilms’ tumor to bone should be considered in a child presenting with a new focal mass overlying bony-structures.

Detection mode of childhood acute lymphoblastic leukaemia relapse and its effect on survival: a Nordic population-based cohort study

Relapse constitutes the greatest threat to event-free survival after completion of treatment for childhood acute lymphoblastic leukaemia (ALL). However, evidence on optimal follow-up schedules is limited. The aims of the present population-based cohort study were to assess the value of current follow-up schedules after completion of Nordic Society of Paediatric Haematology and Oncology ALL protocol treatment and to estimate the impact of relapse detection mode on overall survival (OS). Among 3262 patients diagnosed between 1992 and 2014 and who completed treatment, 338 developed a relapse. Relapse detection was equally distributed between extra visits (50·8%) and scheduled follow-up visits (49·2%). All cases detected at an extra visit and 64·3% of cases detected at a scheduled visit presented with symptoms or objective findings. Neither the mode of detection {adjusted hazard ratio 0·95, [95% confidence interval (CI) 0·61-1·48] for scheduled visits} nor the duration of symptoms was an independent risk factor for OS after relapse. The estimated number of scheduled blood samples needed to diagnose one subclinical relapse during the first 5 years after treatment cessation was 1269 (95% CI 902-1637). In conclusion, based on OS data, scheduled visits after cessation of therapy seem to yield no extra benefit. These results should frame future follow-up strategies.

Inter-clinician delineation variation for a new highly-conformal flank target volume in children with renal tumors: A SIOP-Renal Tumor Study Group international multicenter exercise

BACKGROUND AND PURPOSE

Recently, the SIOP-RTSG developed a highly-conformal flank target volume definition for children with renal tumors. The aims of this study were to evaluate the inter-clinician delineation variation of this new target volume definition in an international multicenter setting and to explore the necessity of quality assurance.

MATERIALS AND METHODS

Six pediatric renal cancer cases were transferred to ten radiation oncologists from seven European countries ('participants'). These participants delineated the pre- and postoperative Gross Tumor Volume (GTVpre/post), and Clinical Target Volume (CTV) during two test phases (case 1-2 and 3-4), followed by guideline refinement and a quality assurance phase (case 5-6). Reference target volumes (TVref) were established by three experienced radiation oncologists. The Dice Similarity Coefficient between the reference and participants (DSCref/part) was calculated per case. Delineations of case 5-6 were graded by four independent reviewers as 'per protocol' (0-4 mm), 'minor deviation' (5-9 mm) or 'major deviation' (≥10 mm) from the delineation guideline using 18 standardized criteria. Also, a major deviation resulting in underestimation of the CTVref was regarded as an unacceptable variation.

RESULTS

A total of 57/60 delineation sets were completed. The median DSCref/part for the CTV was 0.55 without improvement after sequential cases (case 3-4 vs. case 5-6: p = 0.15). For case 5-6, a major deviation was found for 5/18, 12/17, 18/18 and 4/9 collected delineations of the GTVpre, GTVpost, CTV-T and CTV-N, respectively. An unacceptable variation from the CTVref was found for 7/9 participants for case 5 and 6/9 participants for case 6.

CONCLUSION

This international multicenter delineation exercise demonstrates that the new consensus for highly-conformal postoperative flank target volume delineation leads to geometrical variation among participants. Moreover, standardized review showed an unacceptable delineation variation in the majority of the participants. These findings strongly suggest the need for additional training and centralized pre-treatment review when this target volume delineation approach is implemented on a larger scale.

Long Non-Coding RNA XIST Promotes Wilms Tumor Progression Through the miR-194-5p/YAP Axis

Purpose

Although the long non-coding RNA (lncRNA) X inactive-specific transcript (XIST) has been reported to have an anti-tumor effect in multiple malignant tumors, its role in Wilms tumor (WT) progression has not been characterized. Thus, we investigated the underlying mechanism by which XIST regulates WT progression.

Patients and Methods

We performed microarray analysis and real-time quantitative PCR (RT-qPCR) to detect the expression levels of XIST lncRNA, microRNA-194-5p (miR-194-5p), and YAP (yes-associated protein in Hippo pathway) in tumor and matched adjacent normal tissues and blood collected from 49 WT patients. We also conducted bioinformatics analyses to identify differentially expressed genes. We measured the effects of XIST overexpression and knockdown on cell proliferation, apoptosis, migration, and invasion, and its association with the miR-194-5p/YAP pathway in the rhabdoid G401cell line using flow cytometry, transwell assays, immunohistochemistry, Western blot analysis, and the dual luciferase reporter gene assay.

Results

We found that XIST lncRNA levels were increased in blood and tissue samples of WT patients, and this upregulation was significantly correlated with TNM staging and shorter survival time. Notably, we found that XIST upregulation correlated with miR-194-5p downregulation and YAP upregulation in WT tissues, suggesting that XIST regulates the miR-194-5p/YAP pathway. Conversely, XIST downregulation inhibited WT cell proliferation, migration, and invasion and induced apoptosis. Our study revealed the oncogenic role of the lncRNA XIST in WT and demonstrated its role as a competitive endogenous RNA that regulates the miR-194-5p/YAP pathway.

Conclusion

Our study demonstrates XIST’s potential as a clinical prognostic biomarker and therapeutic target for 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.

Improvement of overall survival in the Collaborative Wilms Tumour Africa Project

INTRODUCTION

The Collaborative Wilms Tumour (WT) Africa Project implemented an adapted WT treatment guideline in six centres in sub-Saharan Africa. The primary objectives were to describe abandonment of treatment, death during treatment, event-free survival (EFS) and relapse following implementation. An exploratory objective was to compare outcomes with the baseline evaluation, a historical cohort preceding implementation.

METHODS

The Collaborative WT Africa Project is a multi-centre prospective clinical trial that began in 2014. Funding was distributed to all participating centres and used to cover treatment, travel and other associated costs for patients. Patient characteristics, tumour characteristics and events were described.

RESULTS

In total, 201 WT patients were included. Two-year EFS was 49.9 ± 3.8% when abandonment of treatment was considered an event. Relapse of disease occurred in 21% (42 of 201) of all included patients and in 26% (42 of 161) of those who had a nephrectomy. Programme implementation was associated with significantly higher survival without evidence of disease at the end of treatment (52% vs 68.5%, P = .002), significantly reduced abandonment of treatment (23% vs 12%, P = .009) and fewer deaths during treatment (21% vs 13%, P = .06).

CONCLUSION

This collaborative implementation of an adapted WT treatment guideline, using relatively simple and low-cost interventions, was feasible. Two-year EFS was almost 50%. In addition, a significant decrease in treatment abandonment and an increase in survival at the end of treatment were observed compared to a pre-implementation cohort. Future work should focus on decreasing deaths during treatment and will include enhancing supportive care.

A systematic review of evidence for and against routine surveillance imaging after completing treatment for childhood extracranial solid tumors

BACKGROUND

Regular off-treatment imaging is often used to assess for recurrence of disease after childhood cancer treatment. It is unclear if this increases survival, or what burden surveillance places on patients, families, or health-care services. This systematic review examines the impact of routine surveillance imaging after treatment of pediatric extracranial solid tumors.

METHODS

Collaborative patient and public involvement informed the design and interpretation of this work. Thirteen electronic databases, conference proceedings, and trial registries were searched alongside reference list checking and forward citation searching from 1990 onwards. Studies were screened and data were extracted by two researchers. Risk of bias was assessed using a modified ROBINS-I tool. Relevant outcomes were overall survival, psychological distress indicators, number of imaging tests, cost-effectiveness, and qualitative data regarding experiences of surveillance programs. PROSPERO (CRD42018103764).

RESULTS

Of 17 727 records identified, 55 studies of 10 207 patients were included. All studies used observational methods. Risk of bias for all except one study was moderate, serious, or critical. Data were too few to conduct meta-analysis; however, narrative synthesis was performed. Surveillance strategies varied, and poorly reported, involving many scans and substantial radiation exposure (eg, neuroblastoma, median 133.5 mSv). For most diseases, surveillance imaging was not associated with increased overall survival, with the probable exception of Wilms tumor. No qualitative or psychological distress data were identified.

CONCLUSIONS

At present, there is insufficient evidence to evaluate the effects of routine surveillance imaging on survival in most pediatric extracranial solid tumors. More high-quality data are required, preferably through randomized controlled trials with well-conducted qualitative elements.

Minimally invasive surgery for unilateral Wilms tumors: Multicenter retrospective analysis of 50 transperitoneal laparoscopic total nephrectomies

PURPOSE

To evaluate feasibility and outcomes of minimally invasive surgery (MIS) in Wilms tumor (WT).

METHODS

International multicenter review of MIS total nephrectomies for WT between 2006 and 2018. Medical records of confirmed WT were retrospectively assessed for demographic, imaging, treatment, pathology, and oncological outcome data.

RESULTS

Fifty patients, with a median age of 38 months (6-181), were included in 10 centers. All patients received neoadjuvant chemotherapy, as per SIOP protocol. Median tumor volume post-chemotherapy was 673 mL (18-3331), 16 tumors crossed the lateral border of the spine, and three crossed the midline. Six patients with tumors that crossed the lateral border of the spine (tumor volumes 1560 mL [299-2480]) were converted to an open approach. There was no intraoperative tumor rupture. Overall, MIS was completed in 19% of the 195 nephrectomies for WT presenting during the study period. Tumor was stage I in 29, II in 16, and III in 5, and histology was reported as low in three, intermediate in 42, and high risk in five. Three patients had positive tumor margins. After a median follow-up of 34 months (2-138), there were two local recurrences (both stage I, intermediate risk, 7 and 9 months after surgery) and one metastatic relapse (stage III, high risk, four months after surgery). The three-year event-free survival was 94%.

CONCLUSION

MIS is feasible in 20% of WT, with oncological outcomes comparable with open surgery, no intraoperative rupture, and a low rate of local relapse. Ongoing surveillance is, however, needed to evaluate this technique as it becomes widespread.

Bilateral aniridia and congenital ureteral valve: Role of genetic testing

Background

Congenital aniridia involves total or partial hypoplasia of the iris and is due to a deficiency in PAX6 gene expression. WAGR syndrome is comprised of Wilms tumor, aniridia, genitourinary abnormalities, and intellectual disability. Numerous genitourinary pathologies may be associated with WAGR syndrome, necessitating an evaluation of the genitourinary anatomy. The WT1 is vital for the development of kidneys, ovaries in females, and testes in males. WT1 gene mutations result in a WT1 protein with a decreased ability to bind to DNA, leading to uncontrolled growth, and cell division in the kidney which permits the development of Wilms tumor. A congenital ureteral valve is an exceedingly rare cause of obstructive uropathy.

Results

A renal and bladder ultrasound demonstrated a renal cyst. A voiding cystourethrogram revealed grade 3 vesicoureteral reflux, and a MAG3 renal scan showed ureteropelvic junction obstruction and hydronephrosis. A ureteral stent was inserted at 3 months of age after which the renal cyst resolved. The patient was urinary tract infection‐free at 27 months of age. Genetic testing confirmed a heterozygous alteration in PAX6 (c.495delG, p.Thr166Leufs*41) and no abnormalities of WT1, excluding WAGR syndrome.

Conclusion

The genitourinary risks potentially associated with aniridia necessitate prompt genetic analysis to evaluate for WAGR syndrome.

MiR-155-5p exerts tumor-suppressing functions in Wilms tumor by targeting IGF2 via the PI3K signaling pathway

BACKGROUND

MicroRNA-155-5p (miR-155-5p) has been reported to play an oncogenic role in different human malignancies; however, its role in Wilms tumor (WT) remains unclear.

METHODS

Differentially expressed miRNAs (DE-miRNAs) and mRNAs (DEGs) in WT blood and tissues were identified by using miRNA microarray and RNA-sequencing. Bioinformatics prediction and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses were used to predict the potential functions of DE-miRNAs. DE-miRNAs and DEGs in WT obtained from Gene Expression Omnibus (GEO) and Therapeutically Applicable Research to Generate Effective Treatments (TARGET) were identified by using the "edgeR" package. RT-qPCR was used to explore miR-155-5p and IGF2 expression and their clinical significance in WT specimens. A rhabdoid cell line (G401) and Ewing sarcoma cell line (SK-NEP-1) were used. Immunohistochemical staining, western blotting and dual-luciferase reporter assays were performed to study the mechanisms involved. The CCK-8, flow cytometry, wound healing and transwell assays were performed to identify the effects of miR-155-5p and IGF2 knockdown on cell proliferation, apoptosis, migration and invasion, respectively.

RESULTS

MiR-155-5p was downregulated in both blood and tissues from WT patients who did not receive chemotherapy before surgery but was upregulated in tissues from WT patients who had received chemotherapy before surgery. IGF2, PI3K, AKT and mTOR were found to be upregulated in WT tissues. Additionally, miR-155-5p and IGF2 were significantly correlated with TNM stage and lymphatic metastasis in WT patients. Molecular mechanism exploration indicated that IGF2 was downregulated by miR-155-5p via direct binding to its 3' untranslated region in cell lines. Furthermore, IGF2, PI3K, AKT and mTOR expression was inversely correlated with miR-155-5p expression, and PI3K, AKT and mTOR expression was positively correlated with IGF2 expression in cell culture. Functional studies demonstrated that miR-155-5p upregulation and IGF2 knockdown suppressed cell proliferation, migration and invasion and induced cell apoptosis. Moreover, the tumor-suppressing effects of miR-155-5p in cells were abrogated by miR-155-5p inhibitor treatment.

CONCLUSIONS

Taken together, these findings suggest that miR-155-5p functions as a tumor suppressor in WT through inactivating the PI3K/AKT/mTOR signaling pathway by directly targeting IGF2. Thus, miR-155-5p might be a novel therapeutic target for WT.

[Expression of miR-155-5p in Wilms tumor and its regulatory role in proliferation, migration and apoptosis of Wilms tumor cells in vitro]

OBJECTIVE

explore the expression of miR-155-5p in Wilms tumor and its effect in regulating the proliferation, migration and apoptosis of Wilms tumor cells.

METHODS

Specimens of tumor tissues and paired adjacent tissues were obtained from 40 patients with Wilms tumor for detection of the expression levels of miR-155-5p using RT-qPCR. Wilms tumor cell line G401 was transfected with miR-155-5p mimics and miR-155-5p inhibitor to induce miR-155-5p over-expression and its inhibition, respectively, and the changes in the cell proliferation, migration and apoptosis were assessed using cell counting kit-8 (CCK-8), wound healing assay and fl ow cytometry.

RESULTS

RT-qPCR showed that the expression of miR-155-5p decreased significantly in Wilms tumor tissues as compared with normal kidney tissues and was significantly associated with TNM stage (P < 0.05). In G401 cells, over-expression of miR-155-5p significantly inhibited the cell proliferation and migration and promoted cell apoptosis (P < 0.05), and down-regulation of miR-155-5p obviously enhanced the proliferation and migration and suppressed apoptosis of the cells (P < 0.05).

CONCLUSIONS

miR-155-5p is down-regulated in Wilms tumor and its expression level is correlated with TNM stage. miR-155-5p participates in the progression of Wilms tumor by inhibiting the proliferation and migration and promoting apoptosis of the tumor cells, and may serve as a novel biomarker for diagnosis, therapy and prognostic evaluation of Wilms tumor.

Is surveillance imaging in pediatric patients treated for localized rhabdomyosarcoma useful? The European experience

Background

After the completion of therapy, patients with localized rhabdomyosarcoma (RMS) are subjected to intensive radiological tumor surveillance. However, the clinical benefit of this surveillance is unclear. This study retrospectively analyzed the value of off‐therapy surveillance by comparing the survival of patients in whom relapse was detected by routine imaging (the imaging group) and patients in whom relapse was first suspected by symptoms (the symptom group).

Methods

This study included patients with relapsed RMS after the completion of therapy for localized RMS who were treated in large pediatric oncology hospitals in France, the United Kingdom, Italy, and the Netherlands and who were enrolled in the International Society of Paediatric Oncology Malignant Mesenchymal Tumor 95 (1995‐2004) study, the Italian Paediatric Soft Tissue Sarcoma Committee Rhabdomyosarcoma 96 (1996‐2004) study, or the European Paediatric Soft Tissue Sarcoma Study Group Rhabdomyosarcoma 2005 (2005‐2013) study. The survival times after relapse were compared with a log‐rank test between patients in the imaging group and patients in the symptom group.

Results

In total, 199 patients with relapsed RMS were included: 78 patients (39.2%) in the imaging group and 121 patients (60.8%) in the symptom group. The median follow‐up time after relapse was 7.4 years (interquartile range, 3.9‐11.5 years) for survivors (n = 86); the 3‐year postrelapse survival rate was 50% (95% confidence interval [CI], 38%‐61%) for the imaging group and 46% (95% CI, 37%‐55%) for the symptom group (P = .7).

Conclusions

Although systematic routine imaging is the standard of care after RMS therapy, the majority of relapses were detected as a result of clinical symptoms. This study found no survival advantage for patients whose relapse was detected before the emergence of clinical symptoms. These results show that the value of off‐therapy surveillance is controversial, particularly because repeated imaging may also entail potential harm.

This study assesses the clinical value of radiological surveillance imaging in pediatric patients with rhabdomyosarcoma, which is routinely performed after the completion of therapy. In the majority of patients, relapse is detected because of symptoms, and there is no evidence that early detection by imaging results in improved survival.

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%.

The genetic changes of Wilms tumour

Wilms tumour is the most common renal malignancy of childhood. The disease is curable in the majority of cases, albeit at considerable cost in terms of late treatment-related effects in some children. However, one in ten children with Wilms tumour will die of their disease despite modern treatment approaches. The genetic changes that underpin Wilms tumour have been defined by studies of familial cases and by unbiased DNA sequencing of tumour genomes. Together, these approaches have defined the landscape of cancer genes that are operative in Wilms tumour, many of which are intricately linked to the control of fetal nephrogenesis. Advances in our understanding of the germline and somatic genetic changes that underlie Wilms tumour may translate into better patient outcomes. Improvements in risk stratification have already been seen through the introduction of molecular biomarkers into clinical practice. A host of additional biomarkers are due to undergo clinical validation. Identifying actionable mutations has led to potential new targets, with some novel compounds undergoing testing in early phase trials. Avenues that warrant further exploration include targeting Wilms tumour cancer genes with a non-redundant role in nephrogenesis and targeting the fetal renal transcriptome.

Getting control during follow-up visits: the views and experiences of parents on tumor surveillance after their children have completed therapy for rhabdomyosarcoma or Ewing sarcoma

Purpose

Patients treated for rhabdomyosarcoma (RMS) or Ewing sarcoma (ES) are subject to extensive follow-up after completion of therapy. The aim of this follow-up is to monitor treatment side effects and to detect relapse in an early phase to improve prognosis after relapse. Little is known about parental emotional experiences during this period. We assessed the views and experiences of parents of children treated for RMS or ES on the follow-up examinations after completion of therapy.

Methods

We conducted two focus group meetings and four semi-structured telephone interviews with parents of children treated for RMS or ES in Dutch pediatric oncology centers. Parents of children 0–5 years after end-of-therapy were invited via letters (response rate 31%) and via social media channels of “Dutch Childhood Association for Children and Parents” (VOKK). An inductive thematic approach was used to analyze the data.

Results

In total, 12 parents (fathers, n = 3; mothers, n = 9) of 12 patients treated for RMS (n = 6) or ES (n = 6) participated. Median age at diagnosis for their children was 7.9 years and median time after end-of-treatment was 37 months. Four major themes were identified: content of follow-up, distress and anxiety, search for reassurance and hope, and interaction with others. Parents of children treated for RMS or ES report experiencing significant distress after completion of treatment. They report that their distress was decreased by adequate communication about content, timing, and reasoning behind follow-up.

Conclusion

Physicians should pay attention to the needs of individual parents to reduce distress in the period after completion of therapy.

Impact of Surveillance Imaging Modality on Survival After Recurrence in Patients With Favorable-Histology Wilms Tumor: A Report From the Children's Oncology Group

PURPOSE

The use of computed tomography (CT) for routine surveillance to detect recurrence in patients with Wilms tumor (WT) has increased in recent years. The utility of CT, despite increased risk and cost, to improve outcome for these patients is unknown. We conducted a retrospective analysis with patients enrolled in the fifth National Wilms Tumor Study (NWTS-5) to determine if surveillance with CT correlates with improved overall survival (OS) after recurrence compared with chest x-ray (CXR) and abdominal ultrasound (US).

PATIENTS AND METHODS

Overall, 281 patients with recurrent unilateral favorable-histology WT were reviewed to assess how WT recurrence was detected: sign/symptoms (SS), surveillance imaging (SI) with CT scan, or SI with CXR/US.

RESULTS

The estimated 5-year OS rate after relapse was 67% (95% CI, 61% to 72%). Twenty-five percent of recurrences were detected with SS; 48.5%, with CXR/US; and 26.5%, with CT. Patients with SS had a 5-year OS rate of 59% (95% CI, 46% to 72%) compared with 70% (95% CI, 63% to 77%; P = .23) for those detected by SI. Recurrences detected by CT had a shorter median time from diagnosis to recurrence (0.60 years) compared with SS (0.91 years) or CXR/US (0.86 years; P = .003). For recurrences detected by SI, more tumor foci at relapse ( P < .001) and size of the largest focus greater than 2 cm ( P = .02) were associated with inferior OS. However, there was no difference in OS after relapse when recurrence was detected by CT versus CXR/US (5-year OS rate, 65% v 73%; P = .20).

CONCLUSION

In patients with favorable-histology WT, elimination of CT scans from surveillance programs is unlikely to compromise survival but would result in substantial reduction in radiation exposure and health care costs.