Malignant renal tumours incidence and survival in European children (1978-1997): report from the Automated Childhood Cancer Information System project

Lithocholic bile acid induces apoptosis in human nephroblastoma cells: a non-selective treatment option

Lithocholic bile acid (LCA) has been reported to selectively kill cancer cells within many tumor cell lines including neuroblastoma or glioblastoma. Wilms’ tumor shares similarities with neuro- and glioblastoma. Hence, the aim of the study was to evaluate the effects of LCA on nephroblastoma. To test the effects of LCA, nephroblastoma cell line WT CLS1 was used. SK NEP1 was tested as well. It was originally classified as a nephroblastoma cell line but was meanwhile reclassified as an ewing sarcoma cell line. As control cell lines HEK 293 from embryonic kidney and RC 124 from adult kidney tissue as well as podocytes were used. The effects were evaluated using proliferation assay, caspase activity assay, FACS and Western blot. LCA showed a dose and time-dependent selective effect inducing apoptosis in nephroblastoma cells. However, these effects were not limited to the nephroblastoma cell line but also affected control kidney cell lines and the sarcoma cells; only podocytes are significantly less affected by LCA (at dosages < 200 µm). There were no significant differences regarding the TGR5 receptor expression. The study showed that LCA has a strong, yet unselective effect on all used in vitro cell-lines, sparing the highly differentiated podocytes in lower concentrations. Further studies are needed to verify our results before dismissing LCA as an anti-cancer drug.

Pediatric and young adult renal cell carcinoma

Renal cell carcinoma (RCC) is rare in children but is the most common renal tumor in adults. Pediatric RCC has different clinical characteristics, histopathology, and treatment compared with adult disease. Databases were reviewed from inception to February 2020, identifying 32 publications pertaining to 350 patients under 27 years. Surgery is the cornerstone for cure in localized RCC. Lymph node dissection remains controversial. Conventional radiotherapy has no curative role in RCC; similarly, conventional chemotherapy has not proven to be effective in large cohorts. Pediatric metastatic RCC has a poor outlook. There are no published prospective studies demonstrating which adjuvant therapy could improve outcome. Sunitinib, a tyrosine kinase inhibitor, is recommended in this group despite limited evidence. This review provides an overview for pediatric RCC, including the evolving role of precision medicine.

Targetable gene fusions and aberrations in genitourinary oncology

Gene fusions result from either structural chromosomal rearrangement or aberrations caused by splicing or transcriptional readthrough. The precise and distinctive presence of fusion genes in neoplastic tissues and their involvement in multiple pathways central to cancer development, growth and survival make them promising targets for personalized therapy. In genitourinary malignancies, rearrangements involving the E26 transformation-specific family of transcription factors have emerged as very frequent alterations in prostate cancer, especially the TMPRSS2-ERG fusion. In renal malignancies, Xp11 and t(6;11) translocations are hallmarks of a distinct pathological group of tumours described as microphthalmia-associated transcription factor family translocation-associated renal cell carcinomas. Novel druggable fusion events have been recognized in genitourinary malignancies, leading to the activation of several clinical trials. For instance, ALK-rearranged renal cell carcinomas have shown responses to alectinib and crizotinib. Erdafitinib has been tested for the treatment of FGFR-rearranged bladder cancer. Other anti-fibroblast growth factor receptor 3 (FGFR3) compounds are showing promising results in the treatment of bladder cancer, including infigratinib and pemigatinib, and all are currently in clinical trials.

Diffusion-weighted MRI in the assessment of nephroblastoma: results of a multi-center trial

PURPOSE

To assess the value of diffusion-weighted MRI in the pre-therapeutic evaluation of pediatric renal cortical tumors.

METHODS

This IRB-approved, retrospective multi-center study included 122 pediatric patients with 130 renal tumors, who underwent MRI including DWI before neoadjuvant chemotherapy and nephrectomy. Two radiologists independently assessed each tumor volumetrically, and apparent diffusion coefficient (ADC) values were calculated on a voxel-wise basis, including parameters derived from histogram and texture analysis.

RESULTS

Inter-reader agreement was excellent (ICC 0.717-0.975). For both readers, patients with locally aggressive tumor growth (SIOP 3 stage) or with metastases (M1) had significantly lower 12.5th-percentile ADC values (p ≤ 0.028) compared to those with lower-stage tumors, and the parameter energy differed significantly between patients with M1 and those with M0 status (p ≤ 0.028). Contrast and homogeneity differed significantly between benign nephroblastomatosis and malignant nephroblastoma (p ≤ 0.045, both readers). As compared to all other subtypes, the blastemal subtype demonstrated significantly higher skewness (p ≤ 0.022, both readers) and the diffuse anaplastic subtype demonstrated significantly higher 75th-percentile ADC values (p ≤ 0.042, both readers).

CONCLUSIONS

Diffusion-weighted MRI may be of value in identifying benign nephroblastomatosis and assessing nephroblastoma subtypes. Therefore, further research is warranted to assess its value in risk stratification for pediatric patients with renal tumors in the future.

Renal growth slope in children with congenital and acquired solitary functioning kidneys

Purpose

This study aimed to analyze the renal growth slope in children with congenital and acquired solitary functioning kidneys.

Methods

This retrospective study included all renal ultrasonography examinations performed in children in the agenesis, multicystic dysplastic kidney (MCDK), or nephrectomy group between September 2002 and February 2019. We reviewed the images and recorded the contralateral kidney size only when there was no focal lesion. Linear mixed model or piecewise linear mixed model analyses with a time point of 24 months of age were performed.

Results

There were 132 patients, including 26 patients in the agenesis group, 35 in the MCDK group, and 71 in the nephrectomy group. The nephrectomy group showed the largest baseline kidney size (7.4 cm vs. 5.3 cm in the agenesis group [P<0.001] and 5.2 cm in the MCDK group [P<0.001]) and the smallest overall growth slope (0.04 cm/mo vs. 0.06 cm/mo in the agenesis group [P=0.004] and 0.07 cm/mo in the MCDK group [P<0.001]). However, considering the time point of 24 months for reaching adult renal function, there were significant changes in slope, from 0.1 cm/mo before 24 months of age to 0.03 cm/mo after 24 months of age in all three groups (P<0.001), without a significant difference among the groups.

Conclusion

Significant changes were found in the renal growth slope before and after 24 months of age, with no significant difference between congenital and acquired solitary functioning kidneys.

Maternal lifestyle characteristics and Wilms tumor risk in the offspring: A systematic review and meta-analysis

BACKGROUND

Little is known about the etiology of childhood Wilms tumor (WT) and potentially modifiable maternal risk factors, in particular.

METHODS

Unpublished data derived from the hospital-based, case-control study of the Greek Nationwide Registry for Childhood Hematological Malignancies and Solid Tumors (NARECHEM-ST) were included in an ad hoc conducted systematic literature review and meta-analyses examining the association between modifiable maternal lifestyle risk factors and WT. Eligible data were meta-analysed in separate strands regarding the associations of WT with (a) maternal folic acid and/or vitamins supplementation, (b) alcohol consumption and (c) smoking during pregnancy. The quality of eligible studies was evaluated using the Newcastle-Ottawa Scale.

RESULTS

Effect estimates from 72 cases and 72 age- and sex-matched controls contributed by NARECHEM-ST were meta-analysed together with those of another 17, mainly medium size, studies of ecological, case-control and cohort design. Maternal intake of folic acid and/or other vitamins supplements during pregnancy was inversely associated with WT risk (6 studies, OR: 0.78; 95 %CI: 0.69-0.89, I2 = 5.4 %); of similar size was the association for folic acid intake alone (4 studies, OR: 0.79; 95 %CI: 0.69-0.91, I2 = 0.0 %), derived mainly from ecological studies. In the Greek study a positive association (OR: 5.31; 95 %CI: 2.00-14.10) was found for mothers who consumed alcohol only before pregnancy vs. never drinkers whereas in the meta-analysis of the four homogeneous studies examining the effect of alcohol consumption during pregnancy the respective overall result showed an OR: 1.60 (4 studies, 95 %CI: 1.28-2.01, I2 = 0.0 %). Lastly, no association was seen with maternal smoking during pregnancy (14 studies, OR: 0.93; 95 %CI: 0.80-1.09, I2 = 0.0 %).

CONCLUSIONS

In the largest to-date meta-analysis, there was an inverse association of maternal folic acid or vitamins supplementation with WT risk in the offspring, derived mainly from ecological studies. The association with maternal alcohol consumption found in our study needs to be further explored whereas no association with maternal smoking was detected. Given the proven benefits for other health conditions, recommendations regarding folic acid supplementation as well as smoking and alcohol cessation should apply. The maternal alcohol consumption associations, however, should be further explored given the inherent limitations in the assessment of exposures of the published studies.

Comparison of models of diffusion in Wilms' tumours and normal contralateral renal tissue

Objective

ADC (Apparent Diffusion Coefficient) derived from Diffusion-Weighted Imaging (DWI) has shown promise as a non-invasive quantitative imaging biomarker in Wilms’ tumours. However, many non-Gaussian models could be applied to DWI. This study aimed to compare the suitability of four diffusion models (mono exponential, IVIM [Intravoxel Incoherent Motion], stretched exponential, and kurtosis) in Wilms’ tumours and the unaffected contralateral kidneys.

Materials and methods

DWI data were retrospectively reviewed (110 Wilms’ tumours and 75 normal kidney datasets). The goodness of fit for each model was measured voxel-wise using Akaike Information Criteria (AIC). Mean AIC was calculated for each tumour volume (or contralateral normal kidney tissue). One-way ANOVAs with Greenhouse–Geisser correction and post hoc tests using the Bonferroni correction evaluated significant differences between AIC values; the lowest AIC indicating the optimum model.

Results

IVIM and stretched exponential provided the best fits to the Wilms’ tumour DWI data. IVIM provided the best fit for the normal kidney data. Mono exponential was the least appropriate fitting method for both Wilms’ tumour and normal kidney data.

Discussion

The diffusion weighted signal in Wilms’ tumours and normal kidney tissue does not exhibit a mono-exponential decay and is better described by non-Gaussian models of diffusion.

Liver metastasis at diagnosis in children with nephroblastoma enrolled in SIOP2001 protocol: A French multicentric study

BACKGROUND

Liver metastases are rare in children with Wilms tumor (WT), and their impact on the outcome is unclear.

PATIENTS AND METHODS

The French cohort of patients with WT presenting liver metastases at diagnosis and enrolled in the International Society of Pediatric Oncology (SIOP) 2001 study was reviewed.

RESULTS

From 2002 to 2012, 906 French patients were enrolled in the SIOP2001 trial. Among them, 131 (14%) presented with stage IV WT and 18 (1.9%) had liver metastases at diagnosis. Isolated liver metastases were displayed in four of them. After preoperative chemotherapy, persistent liver disease was reported in 14/18 patients, and 13 of them underwent metastasectomy after nephrectomy. In resected liver lesions, the same histology of the primary tumor was reported for three patients, blastemal cells without anaplasia were identified in one patient with DA-WT, and post-chemotherapy necrosis/fibrosis was identified for the other 10 patients. For the four patients who had liver and lung surgery, both sites had nonviable cells with post-chemotherapy necrosis/fibrosis. Six patients had hepatic radiotherapy. Sixteen patients achieved primary complete remission and were alive at the last follow-up (median follow-up: 6.4 years). The only two deceased patients presented diffuse anaplasia histology. The five-year EFS and OS were 83% (60%-94%) and 88% (66%-97%), respectively.

CONCLUSION

Liver involvement does not appear to be an adverse prognostic factor in metastatic WT. The role of hepatic surgery and radiotherapy remains unclear, and should be carefully considered in case of persistent liver metastases, according to histology and radiological response to other metastatic sites.

Renal tumours in Australian children: 30 years of incidence, outcome and second primary malignancy data from the Australian Childhood Cancer Registry

AIM

This paper describes the incidence and outcomes of childhood renal malignancies in Australia using national population-based data from the Australian Childhood Cancer Registry.

METHODS

De-identified data for children (0-14 years) diagnosed with renal malignancies from 1983 to 2015 inclusive were extracted. Cause-specific (CSS) and event-free survival up to 20 years from diagnosis were estimated using the cohort method. Adjusted excess mortality hazard ratios were calculated using a multivariable flexible parametric survival model. Details relating to second primary malignancies (SPMs) were also examined.

RESULTS

There were 1046 children diagnosed with renal malignancies in Australia between 1983 and 2015 (91% nephroblastoma), generating an annual age-standardised incidence rate of 8 per million children, which remained constant over the study period. CSS was 89% (95% confidence interval = 87-91%) and 88% (86-90%) at 5 and 20 years, respectively, and 5-year event-free survival was 82% (80-84%). Five-year CSS did not change over the study period and was highest for nephroblastoma (91%). Of the 94% of patients achieving remission, 15% relapsed and subsequent 5-year CSS was 49% (40%-58%). Eleven children were diagnosed with SPM (standardised incidence ratio = 2.9, 95% confidence interval = 1.6-5.3, P < 0.001), and five of them (45%) died within 5 years of the second diagnosis.

CONCLUSIONS

Children treated for renal malignancies in Australia have excellent long-term survival, which is unchanged since 1983. SPMs are uncommon following treatment for childhood renal cancer but carry a poor prognosis. Relapse carries a similarly poor prognosis to SPM but is more common. These data are comparable to registry outcomes in similarly developed nations.

Comprehensive analysis of the long non-coding RNA-associated competitive endogenous RNA network reveals novel prognostic biomarkers in Wilms' tumor

Wilms' tumor (WT) is one of the most common types of renal carcinoma in children. The aim of the present study was to construct a competitive endogenous RNA (ceRNA) regulation network and explore novel prognostic biomarkers for WT. The expression profiles were downloaded from The Cancer Genome Atlas database to identify differentially expressed RNAs (DERNAs). Based on the interactions between microRNAs (miRNAs) and mRNAs/long non-coding RNAs (lncRNAs), a ceRNA network was constructed. Functional enrichment analyses were subsequently conducted to explore the functions of the ceRNA-associated DEmRNAs. Survival analysis was performed to screen for prognosis-associated RNAs and the χ² test was used to assess the associations between prognosis-associated RNA expression and histology classification/clinical staging. The present study identified 1,784 lncRNAs, 114 miRNAs and 3,337 mRNAs, which were abnormally expressed in WT compared with that in normal samples. By prediction, pairing and network analysis, a ceRNA network consisting of 38 DElncRNAs, 18 DEmiRNAs and 99 DEmRNAs was established. These DEmRNAs were significantly enriched in pathways associated with the occurrence and development of WT. By combining the expression data with survival analysis, seven prognosis-associated RNAs were identified (P<0.05). Of these seven RNAs, two (zinc finger and BTB domain containing 4; and deleted in lymphocytic leukemia 2) were significantly associated with clinical staging and histology classification. Lastly, the expression levels of the seven RNAs were verified in the Gene Expression Omnibus database. The present study revealed that 7 RNAs might be considered as novel prognostic biomarkers and potential treatment targets for therapy in WT. In addition, the ceRNA regulation network could provide novel strategies for further studies on lncRNAs and miRNAs in WT.

Renal Tumors of Childhood-A Histopathologic Pattern-Based Diagnostic Approach

Renal tumors comprise approximately 7% of all malignant pediatric tumors. This is a highly heterogeneous group of tumors, each with its own therapeutic management, outcome, and association with germline predispositions. Histopathology is the key in establishing the correct diagnosis, and therefore pathologists with expertise in pediatric oncology are needed for dealing with these rare tumors. While each tumor shows different histologic features, they do have considerable overlap in cell type and histologic pattern, making the diagnosis difficult to establish, if based on routine histology alone. To this end, ancillary techniques, such as immunohistochemistry and molecular analysis, can be of great importance for the correct diagnosis, resulting in appropriate treatment. To use ancillary techniques cost-effectively, we propose a pattern-based approach and provide recommendations to aid in deciding which panel of antibodies, supplemented by molecular characterization of a subset of genes, are required.

Methylation Statuses of H19DMR and KvDMR at WT2 in Wilms Tumors in Taiwan

Wilms tumor is the most common pediatric renal malignancy. Several genetic loci have been shown to be associated with its formation. Genetic or epigenetic aberrations at WT1 and WT2 loci have been implicated in the etiology of the majority of sporadic Wilms tumors. In our previous study, most Wilms tumors tested negative for both constitutional mutations and somatic mutations in the WT1 gene. Thus, WT2 may play an important role in these tumors. In the present study, we analyzed the methylation statuses of WT2 at 11p15 using methylation sensitive multiplex ligation-dependent probe amplification in six Wilms tumors. Paternal uniparental disomy at WT2 was observed in two Wilms tumors with epithelial components due to hypermethylation at H19DMR and hypomethylation at KvDMR. Our findings highlight the benefits of testing for 11p15 epigenetic abnormalities to identify Wilms tumors with epithelial components.

Outcome of patients with stage IV high-risk Wilms tumour treated according to the SIOP2001 protocol: A report of the SIOP Renal Tumour Study Group

INTRODUCTION

High-risk (HR) metastatic (stage IV) Wilms tumours (WTs) have a particular poor outcome.

METHODS

Here, we report the results of HR (diffuse anaplastic [DA] or blastemal type [BT]) stage IV WT treated patients according to the HR arm in the SIOP2001 prospective study.

RESULTS

From January 2002 to August 2014, 3559 patients with WT were included in the SIOP2001 trial. Among the 525 patients (15%) with metastatic WT, 74 (14%) had stage IV HR-WT. The median age at diagnosis was 5.5 years (range: 1.4-18.3). Thirty-four patients (47%) had BT-WT and 40 (53%) had DA-WT. Five-year event-free survival rates were 44 ± 17% and 28 ± 15% for BT-WT and DA-WT, respectively (p = 0.09). Five-year overall survival rates were 53 ± 17% and 29 ± 16% for BT-WT and DA-WT, respectively (p = 0.03). Metastatic complete response after preoperative treatment was significantly associated with outcome in univariate and multivariate analyses (hazards ratio = 0.3; p = 0.01). Postoperative radiotherapy of metastatic sites might also be beneficial. Forty-three of 74 patients experienced a relapse or progression predominantly in the lungs (80%). The median time to relapse/progression after diagnosis was 7.3 months (range: 1.6-33.3) and 4.9 months (range: 0.7-28.4) for BT-WT and DA-WT, respectively (p = 0.67). This is the first prospective evidence of inferior survival of stage IV BT-WT as compared with historical intermediate-risk WT. Survival of patients with stage IV DA-WT has not improved compared to the previous SIOP93-01 study.

CONCLUSION

These results call for new treatment approaches for patients with HR stage IV WT.

The role of imaging in the initial investigation of paediatric renal tumours

Imaging has a key role in the assessment of paediatric renal tumours, especially when the initial treatment approach is to proceed to standard chemotherapy without histological confirmation. In Europe, according to the International Society of Paediatric Oncology guidelines, core needle biopsy is not routinely done unless the child is older than 10 years. Between age 6 months and 9 years, the child is treated with a standard regimen of preoperative chemotherapy unless there are concerns about non-Wilms' tumour pathology. Atypical imaging findings could therefore stratify a child into a different treatment protocol, and can prompt the need for pretreatment histology. This review details the latest protocols and techniques used in the assessment of paediatric renal tumours. Important imaging findings are discussed, especially the features that might prompt the need for a pretreatment biopsy. Local radiology practices vary, but both MRI and CT are widely used as routine imaging tests for the assessment of paediatric renal tumours in Europe. Advances in imaging technology and MRI sequences are facilitating the development of new techniques, which might increase the utility of imaging in terms of predicting tumour histology and clinical behaviour. Several of these new imaging techniques are outlined here.

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.

Identification of a five-mRNA signature as a novel potential prognostic biomarker in pediatric Wilms tumor

Background

The aim of this study was to generate a prognostic model to predict survival outcome in pediatric Wilms tumor (WT).

Methods

The data including mRNA expression and clinical information of pediatric WT patients were downloaded from the Therapeutically Available Research to Generate Effective Treatments (TARGET) database. The differentially expressed genes were identified and a prognostic signature of pediatric WT was generated according to the results of univariate and multivariate Cox analysis. Receiver operating characteristic (ROC) curve was used to evaluate the five‐mRNA signature in pediatric Wilms tumor patients. Bootstrap test with 500 times was used to perform the internal validation.

Results

We identified 6,964 differentially expressed mRNAs associated with pediatric WT, including 3,190 downregulated mRNAs and 3,774 up‐regulated mRNAs. Univariate and multivariate Cox analysis identified five mRNAs (SPRY1, SPIN4, MAP7D3, C10orf71, and SPAG11A) to establish a predictive model. The risk score formula is as follows: Risk score = 0.3036*SPIN4 + 0.8576*MAP7D3 −0.1548*C10orf71 −0.7335*SPRY1 −0.2654*SPAG11A. The pediatric WT patients were divided into low‐risk group and high‐risk group based on the median risk score (value = 1.1503). The receiver operating characteristic (ROC) curve analysis revealed good performance of the 5‐mRNA prognostic model (the area under the curve [AUC] was 0.821). Bootstrap test (Bootstrap resampling times = 500) was used to perform the internal validation and revealed that the AUC was 0.822. REACTOME, KEGG, and BIOCARTA pathway analyses demonstrated that these survival‐related genes were mainly enriched in ErbB2 and ErbB3 signaling pathways, and calcium signaling pathway.

Conclusion

The five‐mRNA signature can predict the prognosis of patients with pediatric WT. It has significant implication in the understanding of therapeutic targets for pediatric WT patients. However, further study is needed to validate this five‐mRNA signature and uncover more novel diagnostic or prognostic mRNAs candidates in pediatric WT patients.

Prognostic significance of age in 5631 patients with Wilms tumour prospectively registered in International Society of Paediatric Oncology (SIOP) 93-01 and 2001

BACKGROUND

To enhance risk stratification for Wilms tumour (WT) in a pre-operative chemotherapy setting, we explored the prognostic significance and optimal age cutoffs in patients treated according to International Society of Paediatric Oncology Renal Tumour Study Group (SIOP-RTSG) protocols.

METHODS

Patients(6 months-18 years) with unilateral WT were selected from prospective SIOP 93-01 and 2001 studies(1993-2016). Martingale residual analysis was used to explore optimal age cutoffs. Outcome according to age was analyzed by uni- and multivariable analysis, adjusted for sex, biopsy(yes/no), stage, histology and tumour volume at surgery.

RESULTS

5631 patients were included; median age was 3.4 years(IQR: 2-5.1). Estimated 5-year event-free survival (EFS) and overall survival (OS) were 85%(95%CI 83.5-85.5) and 93%(95%CI 92.0-93.4). Martingale residual plots detected no optimal age cutoffs. Multivariable analysis showed lower EFS with increasing age(linear trend P<0.001). Using previously described age categories, EFS was lower for patients aged 2-4(HR 1.34, P = 0.02), 4-10(HR 1.83, P<0.0001) and 10-18 years(HR 1.74, P = 0.01) as compared to patients aged 6 months-2 years. OS was lower for patients 4-10 years(HR 1.67, P = 0.01) and 10-18 years(HR 1.87, P = 0.04), but not for 2-4 years(HR 1.29, P = 0.23). Higher stage, histological risk group and tumour volume were independent adverse prognostic factors.

CONCLUSION

Although optimal age cutoffs could not be identified, we demonstrated the prognostic significance of age as well as previously described cutoffs for EFS (2 and 4 years) and OS (4 years) in children with WT treated with pre-operative chemotherapy. These findings encourage the consideration of age in the design of future SIOP-RTSG protocols.

An alternative approach to contrast-enhanced imaging: diffusion-weighted imaging and T1-weighted imaging identifies and quantifies necrosis in Wilms tumour

OBJECTIVES

Volume of necrosis in Wilms tumour is informative of chemotherapy response. Contrast-enhanced T1-weighted MRI (T1w) provides a measure of necrosis using gadolinium. This study aimed to develop a non-invasive method of identifying non-enhancing (necrotic) tissue in Wilms tumour.

METHODS

In this single centre, retrospective study, post-chemotherapy MRI data from 34 Wilms tumour patients were reviewed (March 2012-March 2017). Cases with multiple b value diffusion-weighted imaging (DWI) and T1w imaging pre- and post-gadolinium were included. Fractional T1 enhancement maps were generated from the gadolinium T1w data. Multiple linear regression determined whether fitted parameters from a mono-exponential model (ADC) and bi-exponential model (IVIM - intravoxel incoherent motion) (D, D*, f) could predict fractional T1 enhancement in Wilms tumours, using normalised pre-gadolinium T1w (T1wnorm) signal as an additional predictor. Measured and predicted fractional enhancement values were compared using the Bland-Altman plot. An optimum threshold for separating necrotic and viable tissue using fractional T1 enhancement was established using ROC.

RESULTS

ADC and D (diffusion coefficient) provided the strongest predictors of fractional T1 enhancement in tumour tissue (p < 0.001). Using the ADC-T1wnorm model (adjusted R2 = 0.4), little bias (mean difference = - 0.093, 95% confidence interval = [- 0.52, 0.34]) was shown between predicted and measured values of fractional enhancement and analysed via the Bland-Altman plot. The optimal threshold for differentiating viable and necrotic tissue was 33% fractional T1 enhancement (based on measured values, AUC = 0.93; sensitivity = 85%; specificity = 90%).

CONCLUSIONS

Combining ADC and T1w imaging predicts enhancement in Wilms tumours and reliably identifies and measures necrotic tissue without gadolinium.

KEY POINTS

• Alternative method to identify necrotic tissue in Wilms tumour without using contrast agents but rather using diffusion and T 1 weighted MRI. • A method is presented to visualise and quantify necrotic tissue in Wilms tumour without contrast. • The proposed method has the potential to reduce costs and burden to Wilms tumour patients who undergo longitudinal follow-up imaging as contrast agents are not used.

[Imaging of abdominal tumors in childhood and adolescence : Part II: relevant intra-abdominal and retroperitoneal tumor entities]

Abdominal and pelvic tumors in children and adolescents can be manifested intra-abdominally and also often in the retroperitoneum. The most important pediatric primary retroperitoneal space-occupying lesions are nephroblastoma (Wilms' tumor) and neuroblastoma, whereby imaging plays a decisive role in the diagnostics and differentiation of the two entities. Benign tumors of the mesentery and gastrointestinal tract occur more frequently in children than malignant lesions. The benign entities include lipoma, polyps and vascular tumors, such as lymphatic malformations. Of the malignant sarcomas, abdominal rhabdomyosarcomas (RMS) occur relatively often in childhood and adolescence. The most frequent pediatric abdominal lymphoma is Burkitt's lymphoma, an aggressive subtype of non-Hodgkin's lymphoma. Relevant tumor entities in childhood are also germ cell tumors, which originate from the genitals (gonadal) or can be extragonadally manifested. The benignancy or malignancy of germ cell tumors ranges from benign teratomas to highly malignant entities, such as yolk sac tumors. The germ cell tumors, just as all pediatric abdominal mass lesions, show a broad spectrum of tumor aggressiveness, malignancy and therefore also prognosis and mortality for the affected children and adolescents.

Benchmarking Wilms' tumor in multisequence MRI data: why does current clinical practice fail? Which popular segmentation algorithms perform well?

Wilms' tumor is one of the most frequent malignant solid tumors in childhood. Accurate segmentation of tumor tissue is a key step during therapy and treatment planning. Since it is difficult to obtain a comprehensive set of tumor data of children, there is no benchmark so far allowing evaluation of the quality of human or computer-based segmentations. The contributions in our paper are threefold: (i) we present the first heterogeneous Wilms' tumor benchmark data set. It contains multisequence MRI data sets before and after chemotherapy, along with ground truth annotation, approximated based on the consensus of five human experts. (ii) We analyze human expert annotations and interrater variability, finding that the current clinical practice of determining tumor volume is inaccurate and that manual annotations after chemotherapy may differ substantially. (iii) We evaluate six computer-based segmentation methods, ranging from classical approaches to recent deep-learning techniques. We show that the best ones offer a quality comparable to human expert annotations.

Indications and results of diagnostic biopsy in pediatric renal tumors: A retrospective analysis of 317 patients with critical review of SIOP guidelines

OBJECTIVES

According to the Renal Tumor Study Group (RTSG) of the International Society of Paediatric Oncology (SIOP), diagnostic biopsy of renal tumors prior to neoadjuvant chemotherapy is not mandatory unless the presentation is atypical for a Wilms tumor (WT). This study addresses the relevance of this strategy as well as the accuracy and safety of image-guided needle biopsy.

METHODS

Clinical, radiological, and pathological data from 317 children (141 males/176 females, mean age: 4 years, range, 0-17.6) consecutively treated in one SIOP-affiliated institution were retrospectively analyzed.

RESULTS

Presumptive chemotherapy for WT was decided for 182 patients (57% of the cohort), 24 (8%) were operated upfront, and 111 (35%) were biopsied at diagnosis. A non-WT was confirmed after surgery in 5/182 (3%), 11/24 (46%), and 28/111 (25%), respectively. Age at diagnosis was the most commonly (46%) used criterion to go for biopsy but a nine-year threshold should be retrospectively considered more relevant. Tumor volumes of clear cell sarcoma of the kidney and WT were significantly higher than those of other tumors (P = 0.002). The agreement between core-needle biopsy (CNB) and final histology was 99%. No significant morbidity was associated with CNB.

CONCLUSION

The use of SIOP criteria to identify patients eligible for presumptive WT neoadjuvant chemotherapy or upfront surgery avoided biopsy in 65% of children and led to a 97% rate of appropriate preoperative chemotherapy. Image-guided CNB is a safe and accurate diagnostic procedure. The relevance of SIOP biopsy criteria might be improved by using an older age threshold (9 years instead of 6 years) and by adding initial tumor volume.

The diagnostic accuracy and clinical utility of pediatric renal tumor biopsy: Report of the UK experience in the SIOP UK WT 2001 trial

INTRODUCTION

The International Society of Paediatric Oncology (SIOP) protocols recommend preoperative chemotherapy appropriate for Wilms tumors (WTs) in children with renal tumors aged ≥6 months, reserving biopsy for "atypical" cases. The Children's Cancer and Leukaemia Group (CCLG) joined the SIOP-WT-2001 study but continued the national practice of biopsy at presentation.

METHOD

Retrospective study of concordance between locally reported renal tumor biopsies and central pathology review nephrectomy diagnoses of children enrolled by CCLG centers in the SIOP-WT-2001 study.

RESULTS

Biopsy reports were available for 552/787 children with unilateral tumors. 36 of 552 (6.5%) were nondiagnostic: 2 normal tissue, 12 necrotic, 9 insufficient sample, and 13 indeterminate results (disproportionately non-WTs). The sensitivity and specificity of biopsy to identify tumors that did not require SIOP empirical preoperative chemotherapy were 86.0% and 99.6%, respectively. 13 of 548 (2.4%) biopsy results were discordant with nephrectomy; non-WTs other than renal cell carcinoma and clear cell sarcoma of the kidney (CCSK) were poorly recognized. In children aged 6-119 months, 480 of 518 (91.6%) had WT or nephroblastomatosis. 5 of 518 (1%) had benign tumors, and only one diagnosed on biopsy. Biopsy results correctly changed clinical management in 25 of 518 (4.8%), including identifying 19 of 20 CCSKs, but would have led to overtreatment in 5 of 518 (1%) or undertreatment in 4 of 518 (0.8%). In children aged ≥10 years, biopsy correctly changed management in 5 of 19 (26%) cases with no discordance.

CONCLUSION

Biopsy is less effective at identifying non-WTs than WTs and rarely changes management in younger children. Biopsy should be reserved in SIOP protocols for children ≥10 years and in younger children with clinical or radiological features inconsistent with WT.

Wilms tumour event-free and overall survival in Southern and Eastern Europe: Pooled analyses of clinical data from four childhood cancer registries (1999-2017)

BACKGROUND

Wilms tumour (WT) management represents a success story in pediatric oncology. We aimed to assess, for the first time, the event-free survival (EFS) vs. overall survival (OS) in Southern and Eastern Europe (SEE) using harmonised clinical data collected by childhood cancer registries and to identify respective prognostic factors.

METHODS

From 1999 to 2017, data for incident WT cases aged 0-14 years from 3 nationwide (Greece, Belarus and Slovenia) and one regional (Greater Poland) SEE registries were collected following common coding. Kaplan-Meier curves were constructed, and EFS vs. OS values were derived from Cox proportional hazard models by study variables.

RESULTS

A total of 338 WT cases (45.6% males; median age, 3.19 years; age<5 years, 75%) were included in the analyses. Bilateral were 21 tumours (6.2%). Among the 317 unilateral cases, the majority (93.7%) received International Society of Pediatric Oncology-based protocols; EFS_5-year was 85.1%, and OS_5-year 91.1%; both outcomes were significantly worse in stage IV patients or in those with high-risk/unfavourable histology. Relapse rate among high-risk/unfavourable histology cases was 2.3 times higher than among low-intermediate risk/favourable histology cases, with respective death rate 5.6 times higher. Both relapse and death rates increased significantly in patients with advanced anatomical stage and high-risk/unfavourable histology. Finally, significantly worse was the outcome in bilateral tumours (OS_5-year: 76.3%) vs. unilateral non-metastatic tumours (OS_5-year: 94.7%).

CONCLUSIONS

Our results delineate the potential of high-quality childhood cancer registration entailing clinical data to assess predictors of WT outcome over and beyond those derived from enrolment into clinical trials. Specifically, outcomes among children with WT residing in the four participating SEE countries were comparable with those reported by major cooperative international groups, albeit somehow inferior. Despite the excellent overall prognosis, however, subgroups of patients with advanced or bilateral disease and/or high-risk histology still suffer poor outcomes.

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.

Potential benefit of MRI-guided IMRT for flank irradiation in pediatric patients with Wilms' tumor

PURPOSE/OBJECTIVE

Flank irradiation for Wilms' tumor (WT) is currently performed at our institute using a cone-beam computed tomography-guided volumetric modulated arc (VMAT_CBCT) workflow. By adding real-time magnetic resonance imaging (MRI) guidance to the treatment, safety margins could be reduced. The study purpose was to quantify the potential reduction of the planning target volume (PTV) margin and its dosimetric impact when using an MRI-guided intensity modulated radiation therapy (IMRT_MRI) workflow compared to the VMAT_CBCT workflow.

MATERIAL/METHODS

4D-CT, MRI and CBCT scans acquired during preparation and treatment of 15 patients, were used to estimate both geometric, motion and patient set-up systematic (∑) and random (σ) errors for VMAT_CBCT and IMRT_MRI workflows. The mean PTV (PTV_mean) expansion was calculated using the van Herk formula. Treatment plans were generated using five margin scenarios (PTV_mean ± 0, 1 and 2 mm). Furthermore, the IMRT_MRI plans were optimized with a 1.5T transverse magnetic field turned-on to realistically model an MRI-guided treatment. Plans were evaluated using dose-volume statistics (p<.01, Wilcoxon).

RESULTS

Analysis of ∑ and σ errors resulted in a PTV_mean of 5 mm for the VMAT_CBCT and 3 mm for the IMRT_MRI workflows in each orthogonal direction. Target coverage was unaffected by the margin decrease with a mean V_95%=100% for all margin scenarios. For the PTV_mean, an average reduction of the mean dose to the organs at risk (OARs) was achieved with IMRT_MRI compared to VMAT_CBCT: 3.4 ± 2.4% (p<.01) for the kidney, 3.4 ± 2.1% (p<.01) for the liver, 2.8 ± 3.0% (p<.01) for the spleen and 4.9 ± 3.8% (p<.01) for the pancreas, respectively.

CONCLUSIONS

Imaging data in children with WT demonstrated that the PTV margin could be reduced isotropically down to 2 mm when using the IMRT_MRI compared to the VMAT_CBCT workflow. The former results in a dose reduction to the OARs while maintaining target coverage.

The coexistence of a Wilms' tumor and renal cell carcinoma in children: a case report and review of the literature

A combination of a Wilms' tumor (WT) and renal cell carcinoma (RCC) is an extremely rare pediatric renal neoplasm. Its prognosis and clinicopathological features remain unclarified. Herein, we describe a case of the coexistence of a WT and an RCC in a male child aged 5 years and 10 months. The child had symptoms of hematuria for more than 1 month. Although his irises were clear, medical imaging revealed a potential malignant tumor in the left kidney. The patient underwent resection of the left kidney. The pathological diagnosis was the coexistence of a WT and papillary RCC. Negative surgical margins were examined. One month following the resection, chemotherapy with vincristine plus dactinomycin (EE-4A regimen) was commenced. At the 69-month follow-up, there was no recurrence or metastasis. The coexistence of a WT and an RCC in the pediatric population is considered a rare pathological event. At present, there is no standard treatment for these renal neoplasms. In this study, the RCC treatment, which was the same as that applied in cases of WTs, was reasonable.

Weighted gene co‑expression network analysis for identifying hub genes in association with prognosis in Wilms tumor

Wilms tumor (WT) is the most common type of renal malignancy in children. Survival rates are low and high-risk WT generally still carries a poor prognosis. To better elucidate the pathogenesis and tumorigenic pathways of high-risk WT, the present study presents an integrated analysis of RNA expression profiles of high-risk WT to identify predictive molecular biomarkers, for the improvement of therapeutic decision-making. mRNA sequence data from high-risk WT and adjacent normal samples were downloaded from The Cancer Genome Atlas to screen for differentially expressed genes (DEGs) using R software. From 132 Wilms tumor samples and six normal samples, 2,089 downregulated and 941 upregulated DEGs were identified. In order to identify hub DEGs that regulate target genes, weighted gene co-expression network analysis (WGCNA) was used to identify 11 free-scale gene co-expressed clusters. The Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways were annotated using KEGG Orthology Based Annotation System annotation of different module genes. The Search Tool for the Retrieval of Interacting Genes was used to construct a protein-protein interaction network for the identified DEGs, and the hub genes of WGCNA modules were identified using the Cytohubb plugin with Cytoscape software. Survival analysis was subsequently performed to highlight hub genes with a clinical signature. The present results suggest that epidermal growth factor, cyclin dependent kinase 1, endothelin receptor type A, nerve growth factor receptor, opa-interacting protein 5, NDC80 kinetochore complex component and cell division cycle associated 8 are essential to high-risk WT pathogenesis, and they are closely associated with clinical prognosis.

The UMBRELLA SIOP-RTSG 2016 Wilms tumour pathology and molecular biology protocol

On the basis of the results of previous national and international trials and studies, the Renal Tumour Study Group of the International Society of Paediatric Oncology (SIOP-RTSG) has developed a new study protocol for paediatric renal tumours: the UMBRELLA SIOP-RTSG 2016 protocol (the UMBRELLA protocol). Currently, the overall outcomes of patients with Wilms tumour are excellent, but subgroups with poor prognosis and increased relapse rates still exist. The identification of these subgroups is of utmost importance to improve treatment stratification, which might lead to reduction of the direct and late effects of chemotherapy. The UMBRELLA protocol aims to validate new prognostic factors, such as blastemal tumour volume and molecular markers, to further improve outcome. To achieve this aim, large, international, high-quality databases are needed, which dictate optimization and international harmonization of specimen handling and comprehensive sampling of biological material, refine definitions and improve logistics for expert review. To promote broad implementation of the UMBRELLA protocol, the updated SIOP-RTSG pathology and molecular biology protocol for Wilms tumours has been outlined, which is a consensus from the SIOP-RTSG pathology panel.

Evaluation of boost irradiation in patients with intermediate-risk stage III Wilms tumour with positive lymph nodes only: Results from the SIOP-WT-2001 Registry

OBJECTIVE

To evaluate the value of radiotherapy boost omission in patients with intermediate-risk, stage III Wilms tumours (WT) with positive lymph nodes (LN).

METHODS AND MATERIALS

All patients with intermediate-risk, stage III (LN positive) WT consecutively registered in the SIOP-WT-2001 study were included in this analysis. Endpoints were 5-year event-free survival (EFS), loco-regional control (LRC) and overall survival (OS).

RESULTS

Between June 2001 and May 2015, 2,569 patients with stage I to III WT after preoperative chemotherapy were registered in the SIOP-WT-2001 study. Five hundred and twenty-three (20%) had stage III disease, of which 113 patients had stage III due to positive LN only. Of those, 101 (89%) received radiotherapy, 36 of which (36%) received, apart from flank irradiation, a boost dose to the LN positive area. Four patients (4%) did not receive any adjuvant radiotherapy. In eight patients information on radiotherapy was not available. With a median follow-up of 71 months, no difference in 5-year EFS (84% vs. 83%, P = 0.77) and LRC (96% vs. 97%, P = 0.91) was observed between patients receiving a radiotherapy boost and those without boost, respectively. Five-year OS, including salvage therapy, was excellent (boost vs. no boost: 97% vs. 95%, P = 0.58).

CONCLUSIONS

Outcome data demonstrate that omission of the radiotherapy boost to the loco-regional positive lymph nodes in patients with intermediate-risk, stage III WT who receive preoperative chemotherapy and postoperative flank irradiation (14.4 Gy) can be considered a safe approach for future SIOP protocols.

Survival and mortality rates of Wilms tumour in Southern and Eastern European countries: Socioeconomic differentials compared with the United States of America

BACKGROUND

Despite recent therapeutic advancements, Wilms tumour (WT) presents remarkable survival variations. We explored mortality and survival patterns for children (0-14 years) with WT in 12 Southern and Eastern European (SEE) countries in comparison with the United States of America (USA).

METHODS

A total of 3966 WT cases (0-14 years) were registered by a network of SEE childhood cancer registries (N:1723) during available registration periods circa 1990-2016 and surveillance, epidemiology, and end results program (SEER) (N:2243; 1990-2012); mortality data were provided by the respective national statistical services. Kaplan-Meier curves and Cox proportional hazards models were used to assess the role of age, sex, year of diagnosis, urbanisation and Human Development Index (HDI) on overall survival (OS).

RESULTS

Persisting regional variations shape an overall 78% 5-year OS in the participating SEE countries, lagging behind the USA figure (92%, p=0.001) and also reflected by higher SEE mortality rates. Worth mentioning is the gradually escalating OS in SEE (hazard ratio [HR]_{5-year increment}:0.67, 95% confidence interval [CI]:0.60, 0.75) vs. a non-significant 10% improvement in the SEER data, which had a high starting value. OS differentials [two-fold less favourable among children aged 10-14 years, boys and those living in rural SEE areas (HR:1.37; CI:1.10-1.71) or countries with inferior HDI (2-3-fold)] were minimal in the USA.

CONCLUSIONS

Children with WT residing in SEE countries do not equally enjoy the substantial survival gains, especially for those living in rural areas and in lower HDI countries. Noteworthy are steep and sizeable survival gains in SEE along with the newly presented Greek data pointing to achievable survival goals in SEE despite the financial crisis.

The classification of pediatric and young adult renal cell carcinomas registered on the children's oncology group (COG) protocol AREN03B2 after focused genetic testing

BACKGROUND

Renal cell carcinomas (RCCs) are rare in young patients. Knowledge of their pathologic and molecular spectrum remains limited, and no prospective studies have been performed to date in this population. This study analyzes patients diagnosed with RCC who were prospectively enrolled in the AREN03B2 Children's Oncology Group (COG). The objective was to classify these tumors with the aid of focused genetic testing and to characterize their features.

METHODS

All tumors registered as RCC by central review were retrospectively re-reviewed and underwent additional ancillary studies. Tumors were classified according to the 2016 World Health Organization classification system when possible.

RESULTS

In total, 212 tumors were identified, and these were classified as microphthalmia transcription factor (MiT) translocation RCC (MiT-RCC) (41.5%), papillary RCC (16.5%), renal medullary carcinoma (12.3%), chromophobe RCC (6.6%), clear cell RCC (3.3%), fumarate hydratase-deficient RCC (1.4%), and succinate dehydrogenase-deficient RCC (0.5%). Other subtypes included tuberous sclerosis-associated RCC (4.2%), anaplastic lymphoma kinase (ALK)-rearranged RCC (3.8%), thyroid-like RCC (1.4%), myoepithelial carcinoma (0.9%), and unclassified (7.5%). MiT-RCCs were classified as either transcription factor E3 (TFE3) (93.2%) or EB (TFEB) (6.8%) translocations, and characterization of fusion partners was possible in most tumors.

CONCLUSIONS

The current study delineates the frequency of distinct RCC subtypes in a large prospective series of young patients and contributes knowledge to the diagnostic, clinical, and genetic features of MiT-RCC, the most common subtype among this age group. The identification of rare subtypes expands the spectrum of RCC in young patients, supporting the need for a thorough diagnostic workup. These studies may aid in the introduction of specific therapies for different RCC subtypes in the future. Cancer 2018. © 2018 American Cancer Society.

Association between long interspersed nuclear element-1 methylation levels and relapse in Wilms tumors

Background

Wilms tumor (WT) is a curable pediatric renal malignancy, but there is a need for new molecular biomarkers to improve relapse risk-directed therapy. Somatic alterations occur at relatively low frequencies whereas epigenetic changes at 11p15 are the most common aberration. We analyzed long interspersed element-1 (LINE-1) methylation levels in the blastemal component of WT and normal kidney samples to explore their prognostic significance.

Results

WT samples presented a hypomethylated pattern at all five CpG sites compared to matched normal kidney samples; therefore, the averaged methylation levels of the five CpG sites were used for further analyses. WT presented a hypomethylation profile (median 65.0%, 47.4–73.2%) compared to normal kidney samples (median 71.8%, 51.5–77.5%; p < 0.0001). No significant associations were found between LINE-1 methylation levels and clinical–pathological characteristics. We observed that LINE-1 methylation levels were lower in tumor samples from patients with relapse (median methylation 60.5%) compared to patients without relapse (median methylation 66.5%; p = 0.0005), and a receiving operating characteristic curve analysis was applied to verify the ability of LINE-1 methylation levels to discriminate WT samples from these patients. Using a cut-off value of 62.71% for LINE-1 methylation levels, the area under the curve was 0.808, with a sensitivity of 76.5% and a specificity of 83.3%. Having identified differences in LINE-1 methylation between WT samples from patients with and without relapse in this cohort, we evaluated other prognostic factors using a logistic regression model. This analysis showed that in risk stratification, LINE-1 methylation level was an independent variable for relapse risk: the lower the methylation levels, the higher the risk of relapse. The logistic regression model indicated a relapse risk increase of 30% per decreased unit of methylation (odds ratio 1.30; 95% confidence interval 1.07–1.57).

Conclusion

Our results reinforce previous data showing a global hypomethylation profile in WT. LINE-1 methylation levels can be suggested as a marker of relapse after chemotherapy treatment in addition to risk classification, helping to guide new treatment approaches.

Electronic supplementary material

The online version of this article (10.1186/s13148-017-0431-6) contains supplementary material, which is available to authorized users.

Position paper: Rationale for the treatment of Wilms tumour in the UMBRELLA SIOP-RTSG 2016 protocol

The Renal Tumour Study Group of the International Society of Paediatric Oncology (SIOP-RTSG) has developed a new protocol for the diagnosis and treatment of childhood renal tumours, the UMBRELLA SIOP-RTSG 2016 (the UMBRELLA protocol), to continue international collaboration in the treatment of childhood renal tumours. This protocol will support integrated biomarker and imaging research, focussing on assessing the independent prognostic value of genomic changes within the tumour and the volume of the blastemal component that survives preoperative chemotherapy. Treatment guidelines for Wilms tumours in the UMBRELLA protocol include recommendations for localized, metastatic, and bilateral disease, for all age groups, and for relapsed disease. These recommendations have been established by a multidisciplinary panel of leading experts on renal tumours within the SIOP-RTSG. The UMBRELLA protocol should promote international collaboration and research and serve as the SIOP-RTSG best available treatment standard.

Diffusion-weighted MRI and intravoxel incoherent motion model for diagnosis of pediatric solid abdominal tumors

Background

Pediatric retroperitoneal tumors in the renal bed are often large and heterogeneous, and their diagnosis based on conventional imaging alone is not possible. More advanced imaging methods, such as diffusion‐weighted (DW) MRI and the use of intravoxel incoherent motion (IVIM), have the potential to provide additional biomarkers that could facilitate their noninvasive diagnosis.

Purpose

To assess the use of an IVIM model for diagnosis of childhood malignant abdominal tumors and discrimination of benign from malignant lesions.

Study Type

Retrospective.

Population

Forty‐two pediatric patients with abdominal lesions (n = 32 malignant, n = 10 benign), verified by histopathology.

Field Strength/Sequence

1.5T MRI system and a DW‐MRI sequence with six b‐values (0, 50, 100, 150, 600, 1000 s/mm²).

Assessment

Parameter maps of apparent diffusion coefficient (ADC), and IVIM maps of slow diffusion coefficient (D), fast diffusion coefficient (D*), and perfusion fraction (f) were computed using a segmented fitting model. Histograms were constructed for whole‐tumor regions of each parameter.

Statistical Tests

Comparison of histogram parameters of and their diagnostic performance was determined using Kruskal–Wallis, Mann–Whitney U, and receiver‐operating characteristic (ROC) analysis.

Results

IVIM parameters D* and f were significantly higher in neuroblastoma compared to Wilms' tumors (P < 0.05). The ROC analysis showed that the best diagnostic performance was achieved with D* 90^th percentile (area under the curve [AUC] = 0.935; P = 0.002; cutoff value = 32,376 × 10⁻⁶ mm²/s) and f mean values (AUC = 1.00; P < 0.001; cutoff value = 14.7) in discriminating between neuroblastoma (n = 11) and Wilms' tumors (n = 8). Discrimination between tumor types was not possible with IVIM D or ADC parameters. Malignant tumors revealed significantly lower ADC, D, and higher D* values than in benign lesions (all P < 0.05).

Data Conclusion

IVIM perfusion parameters could distinguish between malignant childhood tumor types, providing potential imaging biomarkers for their diagnosis.

Level of Evidence: 4

Technical Efficacy: Stage 2

J. Magn. Reson. Imaging 2018;47:1475–1486.

Is there a socioeconomic variation in survival from renal tumours in children and young people resident in northern England (1968-2012)?

BACKGROUND

Despite strong evidence of a social gradient in cancer survival among UK adults, studies in children and young people remain inconclusive and have not included renal tumours. This study investigated the relationship between socioeconomic status and survival from renal tumours among children and young people.

PROCEDURE

Kaplan-Meier estimation and Cox regression were used to analyse survival for all 209 renal tumours in children and young people (0-24 years) diagnosed 1968-2012 and registered by a specialist population-based registry. Sociodemographic and clinicopathologic variables, including paternal occupation at birth, were also analysed.

RESULTS

No significant disparity in overall renal tumour and Wilms tumour (WT) survival was observed according to paternal social class [p=0.988 and 0.808, respectively]. The strongest predictor of survival was stage, with late stage (III-IV) disease having a 4-fold higher risk of death compared to early stage (I-II) disease [p<0.001]. Similarly, high mortality-risk was seen for late stage WT in children aged 0-14 years (Hazard Ratio=6.37; 95% CI=2.60-15.59).

CONCLUSIONS

This study did not detect a significant social gradient in renal tumour survival. The identification of tumour stage as a strong predictor of survival irrespective of age, necessitates the development of appropriate public health interventions that target early diagnosis and treatment.

Cancer incidence rates and trends among children and adolescents in Piedmont, 1967-2011

In the past, increases in childhood cancer incidence were reported in Europe and North America. The aim of this study is to show updated patterns of temporal behavior using data of the Childhood Cancer Registry of Piedmont (CCRP), a region with approximately 4.5 million inhabitants in North-West Italy. CCRP has been recording incident cases in children (0–14 years) since 1967 and in adolescents (15–19) since 2000. Time trends were estimated as annual percent change (APC) over the 1976–2011 period for children, and over 2000–2011 for both children and adolescents. CCRP registered 5020 incident cases from 1967 to 2011. Incidence rates were 157 per million person-years for children (1967–2011) and 282 for adolescents (2000–2011). From 1976–2011, increasing trends were observed in children for all neoplasms (APC 1.1, 95%CI: 0.8; 1.5) and for both embryonal and non-embryonal tumors: 1.1%, (0.5; 1.6) and 1.2%, (0.7; 1.6), respectively. Increases were observed in several tumor types, including leukemia, lymphoma, central nervous system tumors and neuroblastoma. In 2000–2011, incidence rates showed mostly non statistically significant variations and large variability. The observation of trends over a long period shows that the incidence of most tumors has increased, and this is only partially explained by diagnostic changes. Large rate variability hampers interpretation of trend patterns in short periods. Given that no satisfying explanation for the increases observed in the past was ever found, efforts must be made to understand and interpret this peculiar and still ununderstood pattern of childhood cancer incidence.

A unified pathogenesis for kidney diseases, including genetic diseases and cancers, by the protein-homeostasis-system hypothesis

Every cell of an organism is separated and protected by a cell membrane. It is proposed that harmony between intercellular communication and the health of an organism is controlled by a system, designated the protein-homeostasis-system (PHS). Kidneys consist of a variety of types of renal cells, each with its own characteristic cell-receptor interactions and producing characteristic proteins. A functional union of these renal cells can be determined by various renal function tests, and harmonious intercellular communication is essential for the healthy state of the host. Injury to a kind of renal cells can impair renal function and induce an imbalance in total body health. Every acute or chronic renal disease has unknown etiologic substances that are responsible for renal cell injury at the molecular level. The immune/repair system of the host should control the etiologic substances acting against renal cells; if this system fails, the disease progresses to end stage renal disease. Each renal disease has its characteristic pathologic lesions where immune cells and immune proteins, such as immunoglobulins and complements, are infiltrated. These immune cells and immune proteins may control the etiologic substances involved in renal pathologic lesions. Also, genetic renal diseases and cancers may originate from a protein deficiency or malfunctioning protein under the PHS. A unified pathogenesis for renal diseases, including acute glomerulonephritis, idiopathic nephrotic syndrome, immunoglobulin A nephropathy, genetic renal diseases such as Alport syndrome, and malignancies such as Wilms tumor and renal cell carcinoma, is proposed using the PHS hypothesis.

Renal Tumors of Childhood: Radiologic-Pathologic Correlation Part 1. The 1st Decade: From the Radiologic Pathology Archives

Wilms tumor is the second most common pediatric solid tumor and by far the most common renal tumor of infants and young children. As most tumors are large at presentation and are treated with nephrectomy, the role of imaging is primarily in preoperative planning and evaluation for metastatic disease. However, with treatment protocols increasingly involving use of preoperative (neoadjuvant) chemotherapy (the standard in Europe) and consideration of nephron-sparing surgery, the role of imaging is evolving to include providing initial disease staging information and a presumptive diagnosis to guide therapy. Differential diagnostic considerations include lesions that are clinically benign and others that require more intensive therapy than is used to treat Wilms tumor. In part 1 of this article, the unique histologic spectrum of renal neoplasms of infants and young children is reviewed with emphasis on radiologic-pathologic correlation. Part 2 will focus on renal tumors of older children and adolescents.

Melanotic Xp11 Translocation Renal Cancer Managed With Radical Nephrectomy and IVC Tumor Thrombectomy

Melanotic Xp11 translocation renal cancer is a rarely observed neoplasm primarily affecting adolescents and young adults. Given the paucity of data describing this malignancy, its natural history and subsequent long-term management are not well understood. We report a case of melanotic Xp11 translocation with tumor thrombus extension managed with radical nephrectomy and inferior vena cava (IVC) tumor thrombectomy. To our knowledge, this is the first case report to describe use of conventional tumor thrombectomy techniques in a patient with melanotic Xp11 translocation renal cancer.

[Expression of regulatory T cells and natural killer T cells in peripheral blood of children with Wilms tumor]

OBJECTIVE

To study the changes and clinical significance of CD4⁺CD25⁺CD127^low regulatory T cells (Treg) and CD3⁺CD16⁺CD56⁺ natural killer T cells (NKT) in peripheral blood of children with Wilms tumor.

METHODS

Twenty-one children with Wilms tumor were enrolled as the case group, and twenty-one healthy children for physical examinations were enrolled as the control group. Flow cytometry was used to detect the levels of CD4⁺CD25⁺CD127^low T cells and CD3⁺CD16⁺CD56⁺ T cells in peripheral blood of two groups.

RESULTS

The level of Treg cells in peripheral blood of the case group was significantly lower than in the control group (p<0.05). The level of NKT cells in peripheral blood of the case group was significantly higher than in the control group (p<0.05).

CONCLUSIONS

Treg cells and NKT cells play important roles in the occurrence and development of Wilms tumor. Treg cells and NKT cells may be useful indexes for evaluating immunological function in children with Wilms tumor.