Controversies and advances in the management of Wilms' tumour

Worse Wilms' Tumor Outcomes Associated With Chemical Complementarity for Multiple T-Cell Receptor CDR3-CMV Epitope Pairs

BACKGROUND/AIM

Wilms' tumors are pediatric renal tumors that generally have a good prognosis and outcomes. Viral illnesses have been linked to development of neoplasms and should be considered as a factor that could modulate overall survival.

MATERIALS AND METHODS

We considered recently developed adaptive immune receptor, genomics and bioinformatics approaches to assess the potential impact of cytomegalovirus (CMV) infections in Wilms' tumor.

RESULTS

T-cell receptor (TCR) complementarity determining region-3 (CDR3) amino acid sequences from Wilms' tumor specimens represented by the Therapeutically Applicable Research to Generate Effective Treatments dataset were compared with known anti-CMV TCR CDR3s, indicating that cases representing the anti-CMV TCR CDR3s had worse outcomes. Then, a chemical complementarity scoring approach for the Wilms' tumor, TCR CDR3s and a series of CMV antigens further indicated that cases representing a higher chemical complementarity to the CMV antigens had worse outcomes.

CONCLUSION

Overall, we present a potentially novel method to assess CMV infections and identify patients who could benefit from therapies that address such infections.

Long-Term Outcomes After Abdominal Radiation for Wilms Tumor: A 20-Year Experience

BACKGROUND

As radiation therapy (RT) for Wilms tumor (WT) evolves with more conformal techniques, it is necessary to evaluate patterns of failure and toxicity. We sought to determine the rate of local failure (LF) after abdominal RT in WT, specifically focusing on those with contained rupture treated with whole abdominal and pelvic RT (WAPRT) vs flank RT. Secondary objectives were to determine overall survival (OS), distant failure (DF), and late toxicities.

METHODS

A single institution retrospective study of 54 pediatric patients with WT treated with abdominal RT between May 2000 and October 2022. LF and DF were calculated through cumulative incidence function and OS by Kaplan-Meier method.

RESULTS

The median age was 4.5 years and the median follow-up was 6 years. Most patients (91%) had favorable histology. Only 1 patient experienced LF, 15 months from completion of RT (cumulative incidence 2% at 5 y). All patients who received unilateral flank radiation for contained rupture/spillage (n=13) experienced long-lasting intra-abdominal tumor control. A total of 5 patients experienced a DF at a median of 7 months, all in the lung. No patient relapsed in the lungs after upfront whole lung irradiation (n=16). OS was 96% at 5 years. Among 28 patients who followed through puberty, 4 female patients with prior WAPRT experienced hormonal irregularities/infertility.

CONCLUSIONS

Unilateral flank radiation may be a viable alternative to WAPRT for contained rupture/spillage and should be further explored prospectively. Our results may also be utilized in the future for outcome and toxicity comparison as conformal radiation techniques evolve.

MicroRNA-27a-5p Inhibits Proliferation, Migration, and Invasion and Promotes Apoptosis of Wilms' Tumor Cell by Targeting PBOV1

Wilms' tumor is the most common type of renal tumor in children. MicroRNAs (miRNAs) are small noncoding RNAs that play crucial regulatory roles in tumorigenesis. We aimed to study the expression profile and function of miR-27a-5p in Wilms' tumor. miR-27a-5p expression was downregulated in human Wilms' tumor tissues. Functionally, overexpression of miR-27a-5p promoted cell apoptosis of Wilms' tumor cells. Furthermore, upregulated miR-27a-5p delayed xenograft Wilms' tumor tumorigenesis in vivo. Bioinformatics analysis predicted that miR-27a-5p directly targeted the 3'-untranslated region (3'-UTR) of PBOV1, and luciferase reporter assay confirmed the interaction between miR-27a-5p and PBOV1. The function of PBOV1 in Wilms' tumor was evaluated in vitro, and knockdown of PBOV1 dampened cell migration. In addition, overexpression of PBOV1 antagonized the tumor-suppressive effect of miR-27a-5p in Wilms' tumor cells. Collectively, our findings reveal the regulatory axis of miR-27a-5p/PBOV1 in Wilms' tumor, and miR-27a-5p might serve as a novel therapeutic target in Wilms' tumor.

A 5-year multidisciplinary care outcomes in children with wilms' tumour managed at a tertiary centre: A retrospective observational study

BACKGROUND

Over the last two decades, there has been significant improvement in the outcomes of children with Wilms' tumour (WT) in high income countries (HICs) with approximately 85% survival rate globally. This is partly attributable to a multi-disciplinary team approach to care and the evolution of more robust treatment measures. A previous review in our centre prior to multi-disciplinary team shows a survival rate of 31.48%, However, the survival rates from low- and middle-income countries are still low when compared to HICs due to delays in access to care at all levels, poor to non-existent health insurance coverage, limited workforce resources, weak health-care systems and infrastructure. The aim of this study is to determine the impact of a multi-disciplinary team approach on the treatment outcomes of children with WT.

METHODOLOGY

This is a 5-year retrospective review of all patients managed with WT at the Lagos University Teaching Hospital, Lagos, Nigeria. Information was extracted from the patients' case notes, operation notes and ward admission records. The data were analysed with SPSS 25, and P < 0.05 was considered to be statistically significant.

RESULTS

Forty patients were included in the study; male to female ratio was 1.6:1. The disease occurred in the right kidney in 23 patients (57.5%) and on the left in 17 patients (42.5%). The average duration of symptoms before presentation was 3.6 months (range 1-7 months), majority of patients presented with abdominal masses and were assessed as per unit protocol with abdominal Computerized tomography scan, chest X-ray and abdominal ultrasound scan to assign the patient International Society of Paediatric oncology regimen. The predominant stage at surgery was Stage III 26 (65%), while Stage IV was 9 (22.5%). Morbidity after chemotherapy was 10 (25%). Twenty-five patients (63%) completed chemotherapy while 15 patients (37%) started chemotherapy but defaulted midway. The 5-year survival rate was 75%. Increasing age and male sex were associated with reduced odds of mortality; however, this was not statistically significant. Increased duration of treatment, being treated with chemotherapy alone, as well as advanced tumour stage and histology were associated with increased odds of mortality, however, this was not statistically significant.

CONCLUSION

The development of an institutional WT treatment pathway involving a multidisciplinary team has resulted in improved outcomes. There is need for increased community awareness to improve the time to presentation.

Implications of cell division cycle associated 4 on the Wilm's tumor cells viability via AKT/mTOR signaling pathway

Objective

The aim of present report was to elucidate the effect of cell division cycle associated 4 (CDCA4) on the proliferation and apoptosis of Wilm’s tumor cells, and to further evaluate its underlying mechanism.

Methods

The expression profiles of CDCA4 and clinical information of Wilm’s tumor patients were obtained from public Therapeutically Applicable Research to Generate Effective Treatments (TARGET) database portal. Real-time qPCR and western blot analyses were utilized to determine the expression levels of CDCA4. Gain- and loss-of-function of CDCA4 assays were conducted with transfection technology to investigate the biological role of CDCA4 in Wilm’s tumor cells. Cell counting kit 8 and flow cytometer assays were employed to examine the effect of CDCA4 on the cells proliferation and apoptosis. Protein expression levels of indicated markers in each group of Wilm’s tumor cells were measured by western blot.

Results

The transcriptional expression of CDCA4 was drastically upregulated in Wilm’s tumor tissues according to the public TARGET database and in Wilm’s tumor cells. The cells viability was remarkably reduced whereas the cells apoptosis was increased in CDCA4-knockdown group compared with negative control group. However, CDCA4-overexpression group promoted the cells proliferation and suppressed the cells apoptosis. Furthermore, the protein expression levels of p-AKT, p-mTOR, and Cyclin D1 were significantly reduced after depletion of CDCA4, whereas overexpression of CDCA4 dramatically elevated these markers’ expression levels.

Conclusions

CDCA4 is highly expressed in Wilm’s tumor and promoted the proliferation whereas inhibited the apoptosis of Wilm’s tumor cells through activating the AKT/mTOR signaling pathway.

Genetic Polymorphisms of the TGFB1 Signal Peptide and Promoter Region: Role in Wilms Tumor Susceptibility?

The aim of the present study was to investigate the rs1800468 (G-800A), rs1800469 (C-509T), rs1800470 (C29T), and rs1800471 (G74C) TGFB1 genetic polymorphisms and their haplotype structures in patients with Wilms Tumor (WT) and neoplasia-free controls. The genomic DNA was extracted from 35 WT patients and 160 neoplasia-free children, and the TGFB1 polymorphisms were genotyped by polymerase chain reaction, followed by restriction fragment length polymorphism. The haplotype structures were inferred, and permutation and logistic regression tests were performed to check for differences in haplotype distribution between the control and WT individuals. Positive associations were found in the recessive model for rs1800469 T allele (OR: 8.417; 95% CI: 3.177 to 22.297; P < 0.001) and for the rs1800470 C allele (OR: 3.000; 95% CI: 1.296 to 6.944; P = 0.01). Haplotype analysis revealed a significant negative association between GCTG and WT (OR: 0.236, 95% CI: 0.105 to 0.534; P = 0.0002); by contrast, the GTTG haplotype was associated with increased risk for WT (OR: 12.0; 95% CI: 4.202 to 34.270; P < 0.001). Furthermore, rs1800469 was negatively correlated with tumor size and a trend toward a positive correlation for capsular invasion was observed in the dominant model (Tau-b: −0.43, P = 0.02 and tau-b: 0.5, P = 0.06, respectively). This is the first study with rs1800468, rs1800469, rs1800470, and rs1800471 TGFB1 polymorphisms in WT, and our results suggest that the TGFB1 promoter and signal peptide region polymorphisms may be associated with WT susceptibility and clinical presentation.

Diagnostic Errors in Wilms' Tumors: Learning From Our Mistakes

Aim: This study aimed to analyze clinical characteristics and image findings in patients initially diagnosed with renal masses and treated on the Société Internationale d'Oncologie Pédiatrique (SIOP) 2001 protocol for Wilms tumor (WT) that eventually were diagnosed with different pathologies. Methods: We reviewed the preoperative symptoms, laboratory tests, and images of patients who were initially treated for WT and proved to have other diagnoses. Data from these patients were compared to those of the last 10 patients with WT and the last 10 patients with neuroblastoma (NBL) treated at a single institution. Results: From June 2001 to December 2020, we treated 299 patients with NBL and 194 with WT. Five patients treated with preoperative chemotherapy for WT were postoperatively diagnosed with NBL (one patient had bilateral renal masses and one with multifocal xanthogranulomatous pyelonephritis). Three underwent nephrectomy, two biopsies only, and one adrenalectomy due to intraoperative characteristics. Regarding clinical presentation, abdominal mass or swelling was very suggestive of WT (p = 0.011); pain, although very prevalent in the study group (67%), was not statistically significant, as well as intratumoral calcifications on computed tomography (CT) (67%). Urinary catecholamines were elevated in all patients mistreated for WT with the exception of the patient with pyelonephritis in which it was not collected. Conclusion: Some pathologies can be misdiagnosed as WT, especially when they present unspecified symptoms and dubious images. Diagnostic accuracy was 98.1%, which highlights the quality of the multidisciplinary team. Abdominal mass or swelling is highly suggestive of WT, especially in the absence of intratumoral calcifications on CT. If possible, urinary catecholamines should be collected at presentation as they help in the differential diagnosis of NBL.

Absence of the TRIP13 c.1060C>T Mutation in Wilms Tumor Patients From Pakistan

BACKGROUND AND AIM

Wilms tumor (WT) is the most common childhood malignant renal tumor. Germline mutations in several WT predisposition genes have been identified. However, the fundamental cause of most WT patients remains unexplained. Recently, a founder mutation, c.1060C>T (p. Arg254X) in a mitotic spindle checkpoint gene, TRIP13, was reported in 5 unrelated children with WT from the United Kingdom, of Pakistani descent from Azad Kashmir region. This observation suggests other children with WT in Pakistan may also harbor this mutation. We conducted the first study to assess the contribution of TRIP13 c.1060C>T mutation to WT in Pakistan.

MATERIALS AND METHODS

Constitutional genomic DNA from 68 Pakistani individuals including unrelated WT cases (n=26) and one (n=10) or both (n=32) of their parent(s) were screened for the TRIP13 c.1060C>T mutation using DNA sequence analysis. We also included positive controls in the analyses.

RESULTS

The median age of WT diagnosis was 3.0 years (range, 0.75 to 10). The TRIP13 c.1060C>T mutation was not found in any WT patient (n=26) or their parents (n=42). Twenty-four patients (92.4%) presented with unilateral tumor and 2 patients (7.7%) were diagnosed with synchronous bilateral WT. Thirteen patients (50%) reported parental consanguinity. Thirteen patients (50.0%) belonged to the Punjabi ethnicity and 1 patient (3.8%) had a Kashmiri background. Four patients (16.7%) reported a family history of WT or other malignancies. The predominant histologic subtype was stromal (46.2%). The majority of patients presented with >5 cm of tumor size (81%). None of the patients had a personal or family history of congenital anomalies, or associated genetic syndromes.

CONCLUSIONS

Our findings suggest that TRIP13 c.1060C>T mutation may be infrequent in Pakistani WT cases. Further evaluation of this mutation in a large number of WT patients of Kashmiri heritage and various ethnic backgrounds from Pakistan is warranted.

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.

Customized approach for upfront or delayed resection using radiological criteria in unilateral, nonmetastatic pediatric renal tumors: A prospective study

BACKGROUND

The availability of robust, equivalent data regarding outcomes for upfront or delayed surgery for renal tumors in children leads to a dilemma in selecting the initial treatment. Imaging criteria associated with the probability of rupture or incomplete resection may provide a more objective assessment for customization for the timing of surgery.

PROCEDURE

Eighty-three children with unilateral, nonmetastatic renal tumors were enrolled between January 2012 and April 2018. Upfront nephrectomy was performed in the absence or delayed surgery (after a biopsy and chemotherapy) in the presence of one or more imaging-based high-risk features, including perinephric spread or adjacent organ infiltration, tumors crossing the midline, intravascular thrombus, and extensive adenopathy. Post hoc analysis for interobserver concordance for high-risk imaging features was also performed.

RESULTS

The upfront surgery group (19) had predominantly stage I or II diseases (89%) and the histological types were Wilms (13), non-Wilms (5) renal tumor, and an inflammatory lesion. The delayed surgery group had 60% with stage I or II diseases and the histological types were Wilms (60) and non-Wilms (4) tumor. In addition, high-risk pathology was identified in nine patients. Overall, 27 patients with Wilms tumors required radiotherapy and anthracycline because of stage III disease, including one in the immediate surgery group. The event-free and overall survival (OS) at a median follow-up of 39 months for Wilms tumor are 88% (95% confidence interval [CI]: 78.5-94.9%) and 89% (95% CI: 81.4-96.6%), 85.1% (95% CI: 73.8-93.4%) and 86.5% (95% CI: 77.4-95.8%) for the delayed, and 100% event-free survival as well as OS (P = .1) in the upfront surgery group.

CONCLUSION

A customized approach pivoted on image-based high-risk features facilitates identification of patients with early-stage renal tumor when the timing of surgery is tailored. Moreover, non-Wilms tumor and high-risk pathology are also identified.

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.

The Iroquois homeobox proteins IRX3 and IRX5 have distinct roles in Wilms tumour development and human nephrogenesis

Wilms tumour is a paediatric malignancy with features of halted kidney development. Here, we demonstrate that the Iroquois homeobox genes IRX3 and IRX5 are essential for mammalian nephrogenesis and govern the differentiation of Wilms tumour. Knock‐out Irx3⁻/Irx5⁻ mice showed a strongly reduced embryonic nephron formation. In human foetal kidney and Wilms tumour, IRX5 expression was already activated in early proliferative blastema, whereas IRX3 protein levels peaked at tubular differentiation. Accordingly, an orthotopic xenograft mouse model of Wilms tumour showed that IRX3^−/− cells formed bulky renal tumours dominated by immature mesenchyme and active canonical WNT/β‐catenin‐signalling. In contrast, IRX5^−/− cells displayed activation of Hippo and non‐canonical WNT‐signalling and generated small tumours with abundant tubulogenesis. Our findings suggest that promotion of IRX3 signalling or inhibition of IRX5 signalling could be a route towards differentiation therapy for Wilms tumour, in which WNT5A is a candidate molecule for enforced tubular maturation. © 2018 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of Pathological Society of Great Britain and Ireland.

HMGA2 overexpression predicts relapse susceptibility of blastemal Wilms tumor patients

Wilms tumor (WT) is an embryonal malignant neoplasm of the kidney that accounts for 6-7% of all childhood cancers. WT seems to derive from multipotent embryonic renal stem cells that have failed to differentiate properly. Since mechanisms underlying WT tumorigenesis remain largely unknown, the aim of this study was to explore the expression of embryonic stem cell (ESC) markers in samples of WT patients after chemotherapy treatment SIOP protocol, as the gene expression patterns of ESC are like those of most cancer cells. We found that expression of ESC markers is heterogeneous, and depends on histological WT components. Interestingly, among ESC markers, HMGA2 was expressed significantly stronger in the blastemal component than in the stromal and the normal kidney. Moreover, two subsets of patients of WT blastemal type were identified, depending on the expression levels of HMGA2. High HMGA2 expression levels were significantly associated with a higher proliferation rate (p=0.0345) and worse patient prognosis (p=0.0289). The expression of HMGA2 was a stage-independent factor of clinical outcome in blastemal WT patients. Our multivariate analyses demonstrated the association between LIN28B-LET7A-HMGA2 expression, and the positive correlation between HMGA2 and SLUG expression (p=0.0358) in blastemal WT components. In addition, patients with a poor prognosis and high HMGA2 expression presented high levels of MDR3 (multidrug resistance transporter). Our findings suggest that HMGA2 plays a prominent role in the pathogenesis of a subset of blastemal WT, strongly associated with relapse and resistance to chemotherapy.

Tumor Screening in Beckwith-Wiedemann Syndrome: Parental Perspectives

Children with Beckwith-Wiedemann Syndrome (BWS) and Isolated Hemihypertrophy (IHH) are at an increased risk for developing tumors. Tumor screening in this population is currently being reassessed by several groups and the effect on patients and patient-families has been argued both as a reason to screen and not to screen. Parental perspectives on this topic have never been systematically addressed for the BWS population. Here, we conducted a parent-based survey to evaluate knowledge and attitudes toward tumor screening in patients affected by BWS/IHH. A total of 261 surveys were completed. Overall, parents reported that screening decreased their worry and did not feel that screening increased worry or created a burden. This effect was observed across various demographic variables and other factors examined. Almost all significant differences observed could be attributed to parental knowledge of tumor risk. Parents who correctly identified their child's tumor risk were more likely to agree with stratified screening recommendations according to BWS type and risk, and were less likely to feel worried if recommendations were changed. These results highlight the need to educate families about their child's genetic type and tumor risk in order to facilitate an informed decision about tumor screening.

Multidrug resistance transporter profile reveals MDR3 as a marker for stratification of blastemal Wilms tumour patients

Wilms tumour (WT) is the most common renal tumour in children. Most WT patients respond to chemotherapy, but subsets of tumours develop resistance to chemotherapeutic agents, which is a major obstacle in their successful treatment. Multidrug resistance transporters play a crucial role in the development of resistance in cancer due to the efflux of anticancer agents out of cells. The aim of this study was to explore several human multidrug resistance transporters in 46 WT and 40 non-neoplastic control tissues (normal kidney) from patients selected after chemotherapy treatment SIOP 93–01, SIOP 2001. Our data showed that the majority of the studied multidrug resistance transporters were downregulated or unchanged between tumours and control tissues. However, BCRP1, MDR3 and MRP1 were upregulated in tumours versus control tissues. MDR3 and MRP1 overexpression correlated with high-risk tumours (SIOP classification) (p = 0.0022 and p < 0.0001, respectively) and the time of disease-free survival was significantly shorter in patients with high transcript levels of MDR3 (p = 0.0359). MDR3 and MRP1 play a role in drug resistance in WT treatment, probably by alteration of an unspecific drug excretion system. Besides, within the blastemal subtype, we observed patients with low MDR3 expression were significantly associated with a better outcome than patients with high MDR3 expression. We could define two types of blastemal WT associated with different disease outcomes, enabling the stratification of blastemal WT patients based on the expression levels of the multidrug resistance transporter MDR3.

Pediatric oncologic endosurgery

Despite increasing popularity of minimal-invasive techniques in the pediatric population, their use in diagnosis and management of pediatric malignancy is still debated. Moreover, there is limited evidence to clarify this controversy due to low incidence of each individual type of pediatric tumor, huge diversity of the disease entity, heterogeneity of surgical technique, and lack of well-designed studies on pediatric oncologic minimal-invasive surgery. However, a rapid development of medical instruments and technologies accelerated the current trend toward less invasive surgery, including oncologic endosurgery. The aim of this article is to review current literatures about the application of the minimal-invasive approach for pediatric tumors and to give an overview of the current status, indications, individual techniques, and future perspectives.

Phenotype, cancer risk, and surveillance in Beckwith-Wiedemann syndrome depending on molecular genetic subgroups

Patients with Beckwith-Wiedemann syndrome (BWS) have an increased risk to develop cancer in childhood, especially Wilms tumor and hepatoblastoma. The risk varies depending on the cause of BWS. We obtained clinical and molecular data in our cohort of children with BWS, including tumor occurrences, and correlated phenotype and genotype. We obtained similar data from larger cohorts reported in the literature. Phenotype, genotype and tumor occurrence were available in 229 of our own patients. Minor differences in phenotype existed depending on genotype/epigenotype, similar to earlier studies. By adding patients from the literature, we obtained data on genotype and tumor occurrence of in total 1,971 BWS patients. Tumor risks were highest in the IC1 (H19/IGF2:IG-DMR) hypermethylation subgroup (28%) and pUPD subgroup (16%) and were lower in the KCNQ1OT1:TSS-DMR (IC2) subgroup (2.6%), CDKN1C (6.9%) subgroup, and the group in whom no molecular defect was detectable (6.7%). Wilms tumors (median age 24 months) were frequent in the IC1 (24%) and pUPD (7.9%) subgroups. Hepatoblastoma occurred mostly in the pUPD (3.5%) and IC2 (0.7%) subgroups, never in the IC1 and CDKN1C subgroups, and always before 30 months of age. In the CDKN1C subgroup 2.8% of patients developed neuroblastoma. We conclude tumor risks in BWS differ markedly depending on molecular background. We propose a differentiated surveillance protocol, based on tumor risks in the various molecular subgroups causing BWS. © 2016 Wiley Periodicals, Inc.

Results of Therapy for Wilms Tumor and Other Malignant Kidney Tumors: A Report From the Chilean Pediatric National Cancer Program (PINDA)

OBJECTIVE

The aim of this study was to analyze the survival of children with Wilms tumor and other malignant renal tumors treated with the TWPINDA-99 protocol.

MATERIALS AND METHODS

Between January 1999 and December 2013, 226 patients were registered on this trial, based on National Wilms Tumor Study-5. Patient characteristics and survival were evaluated.

RESULTS

Two hundred seven patients were diagnosed with Wilms tumor, which represented 91.6% of renal tumors. The male to female ratio was 0.7:1. The median age at diagnosis was 3.3 years. Stage III was the most frequent (39.2%). Metastatic disease was present in 16.7% of the cases. Synchronous bilateral disease was observed in 9.3% of the cases. Favorable histology was diagnosed in 93.6% and anaplastic histology in 6.4% of the patients. Median follow-up was 7.5 years. Ten-year event-free survival and overall survival (OS) for assessable patients with Wilms tumor (n=192) were 82.0% and 89.9%, respectively. OS for patients with stage I was 100% (n=36), stage II: 97.1% (n=35), stage III: 88.6% (n=71), stage IV: 77.9% (n=32), and stage V: 80.8% (n=18). OS for favorable histology (n=180) and anaplastic histology tumors (n=12) were 91.0% and 72.9%, respectively. Other malignant renal tumors had a poorer survival.

CONCLUSION

Prognosis for patients with Wilms tumor treated on TWPINDA-99 seems to be better than previous national trials and is similar to developed countries.

Biomarkers for Wilms Tumor: A Systematic Review

PURPOSE

Wilms tumor is the most common childhood renal malignancy and the fourth most common childhood cancer. Many biomarkers have been studied but there has been no comprehensive summary. We systematically reviewed the literature on biomarkers in Wilms tumor to quantify the prognostic implications of the presence of individual tumor markers.

MATERIALS AND METHODS

We searched for English language studies from 1980 to 2015 performed in patients younger than 18 years with Wilms tumor and prognostic data. The protocol was conducted per PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. Two reviewers abstracted data in duplicate using a standard evaluation form. We performed descriptive statistics, then calculated relative risks and 95% confidence intervals for markers appearing in multiple level II or III studies.

RESULTS

A total of 40 studies were included examining 32 biomarkers in 7,381 patients with Wilms tumor. Studies had a median of 61 patients, 24 biomarker positive patients per series and a median followup of 68.4 months. Median percentages of patients with stages 1, 2, 3, 4 and 5 tumors were 28.5%, 26.4%, 24.5%, 14.1% and 1.7%, respectively, and 10.2% had anaplasia. The strongest negative prognostic association was loss of heterozygosity at 11p15, with a risk of recurrence of 5.00, although loss of heterozygosity at 1p and gain of function at 1q were also strongly linked to increased recurrence (2.93 and 2.86, respectively).

CONCLUSIONS

Several tumor markers are associated with an increased risk of recurrence or a decreased risk of overall survival in patients with Wilms tumor. These data suggest targets for development of diagnostic tests and potential therapies.

Task sharing within a managed clinical network to improve child health in Malawi

BACKGROUND

Eighty per cent of Malawi's 8 million children live in rural areas, and there is an extensive tiered health system infrastructure from village health clinics to district hospitals which refers patients to one of the four central hospitals. The clinics and district hospitals are staffed by nurses, non-physician clinicians and recently qualified doctors. There are 16 paediatric specialists working in two of the four central hospitals which serve the urban population as well as accepting referrals from district hospitals. In order to provide expert paediatric care as close to home as possible, we describe our plan to task share within a managed clinical network and our hypothesis that this will improve paediatric care and child health.

PRESENTATION OF THE HYPOTHESIS

Managed clinical networks have been found to improve equity of care in rural districts and to ensure that the correct care is provided as close to home as possible. A network for paediatric care in Malawi with mentoring of non-physician clinicians based in a district hospital by paediatricians based at the central hospitals will establish and sustain clinical referral pathways in both directions. Ultimately, the plan envisages four managed paediatric clinical networks, each radiating from one of Malawi's four central hospitals and covering the entire country. This model of task sharing within four hub-and-spoke networks may facilitate wider dissemination of scarce expertise and improve child healthcare in Malawi close to the child's home.

TESTING THE HYPOTHESIS

Funding has been secured to train sufficient personnel to staff all central and district hospitals in Malawi with teams of paediatric specialists in the central hospitals and specialist non-physician clinicians in each government district hospital. The hypothesis will be tested using a natural experiment model. Data routinely collected by the Ministry of Health will be corroborated at the district. This will include case fatality rates for common childhood illness, perinatal mortality and process indicators. Data from different districts will be compared at baseline and annually until 2020 as the specialists of both cadres take up posts.

IMPLICATIONS OF THE HYPOTHESIS

If a managed clinical network improves child healthcare in Malawi, it may be a potential model for the other countries in sub-Saharan Africa with similar cadres in their healthcare system and face similar challenges in terms of scarcity of specialists.

Wilms' tumour in African children: Can an institutional approach improve outcome?

BACKGROUND

The poor outcome for patients with Wilms' tumour (WT) in developing countries has been predicated on late presentation, poverty and low rate of chemotherapeutic access. This study aims to evaluate the effects of an institutionalised approach to improving outcome for patients managed in a tertiary hospital in Nigeria.

MATERIALS AND METHODS

Oncology records of children diagnosed with WT between 2009 and 2013 were analysed for therapy completion and other prognostic parameters. Ensuing data were then compared with those from other centres in Africa.

RESULTS

Compared with results from some local and African studies, the therapy completion rate was higher (60%) with a survival rate among this group being between 1 and 4 years. No patient was lost to follow-up because of unavailability or unaffordability of cytotoxic agents.

CONCLUSION

This study shows that an institutionalised approach can help to improve access to anti-cancer drugs, reduce the rate of loss to follow-up and thus improve outcome. There is however need to improve on patient-doctor communication, form support groups and establish a WT registry.

Malignant renal tumors in childhood: report of 54 cases treated at a single institution

BACKGROUND

Wilms tumor is the most common primary renal malignancy occurring in childhood. Significant improvement has been made in the treatment of children with Wilms tumor. However, the treatment of patients with non-Wilms renal tumors remains challenging.

METHODS

Between 1991 and 2010, 70 children with renal tumors were diagnosed at a single institution. Fifty-four patients were histologically confirmed and divided into three groups, including 42 Wilms tumors, seven clear cell sarcomas of kidney, and five malignant rhabdoid tumors. Most patients underwent unilateral nephrectomy and lymph node sampling followed by adjuvant chemotherapy. Twenty-one of these patients subsequently received radiotherapy.

RESULTS

During follow-up, 12 patients died of progressive disease and one died of operative mortality. One patient with unilateral pleural metastases subsequently underwent hematopoietic stem cell transplantation. The median survival time of all patients was 88 months. Children under 2 years of age at diagnosis with Wilms tumor or clear cell sarcoma of kidney had an excellent survival rate of 100% compared to the 0% survival rate of MRT.

CONCLUSION

Younger age at diagnosis bore a better prognosis than did older age, whereas a diagnosis of malignant rhabdoid tumor portended a worse prognosis. Younger patients and appropriate treatment may have contributed to the improved prognosis of clear cell sarcoma of kidney.

Evaluation of CITED1, SIX1, and CD56 protein expression for identification of blastemal elements in Wilms tumor

OBJECTIVES

Successful further treatment of Wilms tumors (WTs) after preoperative chemotherapy and surgery depends on correct histopathologic risk stratification, including quantification of remaining blastemal elements. In the present study, we assessed the usefulness of protein markers for the detection of WT blastema.

METHODS

Expression of the candidate blastemal protein markers CITED1, SIX1, and CD56 was evaluated by immunofluorescence regarding sensitivity and specificity for staining blastema in a tissue microarray containing cores from 30 WTs, a small number of rarer pediatric renal neoplasms, and normal postnatal kidney.

RESULTS

CITED1, SIX1, and CD56 were expressed in blastema in 100%, 89%, and 74%, respectively, of the WTs with this component present. However, they were also expressed in 64%, 25%, and 79%, respectively, of epithelial WT elements and 48%, 52%, and 62%, respectively, of stromal WT elements.

CONCLUSIONS

SIX1 showed the highest specificity, CITED1 the highest sensitivity, and CD56 low specificity and sensitivity for detection of postchemotherapy WT blastema. Cytokeratin staining proved to be a useful way to determine rudimentary tubular elements not readily recognized by routine staining.

Establishment of a patient-derived Wilms' tumor xenograft model: a promising tool for individualized cancer therapy

OBJECTIVE

Lack of appropriate approaches that reliably predict response of Wilms' tumor (WT) to anticancer agents remains a major deficiency in clinical practice of individualized cancer therapy. The aim of this study was to establish a patient-derived tumor tissue (PDTT) xenograft model of WT for individualized chemotherapeutic regimen selection in accordance with the patient's tumor nature.

MATERIAL AND METHODS

Tumor specimens of a primary WT were orthotopically implanted into three nude mice, and after 4 weeks xenografts were harvested for serial heterotopic transplantation in 20 nude mice that were divided into three experimental groups and one control group. In vitro and in vivo chemosensitivity to doxorubicin, actinomycin-D, and vincristine were evaluated. Hematoxylin and eosin (H&E) staining and immunohistochemical examination with desmin, vimentin, myogenin, and neuron-specific enolase (NSE) were also applied to determine histological stability of the xenograft during serial transplantation compared with the original tumor tissue.

RESULTS

The xenograft model was successfully established. Histopathologic characteristics of the xenograft tumors were similar to the patient's tumor. Early passage of the PDTT showed a similar chemosensitivity pattern to the original tumor tissue.

CONCLUSIONS

PDTT xenograft of WT provides an appropriate model for individualized cancer therapeutic regimen selection by means of its biological stability compared with original patient's tumor.

Wilms' tumor: biology, diagnosis and treatment

Wilms' tumor is the commonest renal tumor of childhood affecting one in 10,000 children. It is also one of the successes of paediatric oncology with long term survival above 90% for localised disease and 75% for metastatic disease. Successful management of Wilms' tumor necessitates meticulous attention to correct staging of the tumor and a collaborative effort between paediatric oncologists, specialist surgeons, radiologists, pathologists, and radiation oncologists. Although current treatment protocols are based on risk assignment to minimise toxicity for low risk patients and improve outcomes for those with high risk disease, challenges remain in identifying novel molecular, histological and clinical risk factors for stratification of treatment intensity. Knowledge about Wilms' tumor biology and treatment is evolving rapidly and remains a paradigm for multimodal malignancy treatment. Future efforts will focus on the use of biomarkers to improve risk stratification and the introduction of newer molecularly targeted therapies that will minimise toxicity and improve the outcomes for patients with unfavourable histology and recurrent disease. The aim of this article is to summarise advances in our understanding of the biology of Wilms' tumor and to describe the current approaches to clinical management of patients.

Comparative genomic hybridization of Wilms' tumor

Cytogenetic analysis of solid tumors including Wilms' tumor is challenging due to poor chromosome morphology, complexity of abnormalities, and to the possibility of stromal cell overgrowth in tissue culture. Molecular cytogenetic techniques such as chromosomal comparative genomic hybridization (CGH) have improved the diagnosis of chromosomal aberrations in Wilms' tumor since they can provide results based on the analysis of DNA from nondividing cells. However, chromosomal CGH provides only a limited resolution across the whole genome, which is not different than routine cytogenetic analysis (gains or losses of less than one chromosome band or 10 Mb are not detectable by routine cytogenetics or chromosomal CGH). More recently, the development of genomic arrays opened the possibility of assessing the whole genome at a much higher resolution at a sub-microscopic or sub-band level. Based on the principle of chromosomal CGH, this approach, frequently termed array-CGH, opens the possibility to find invisible changes at the whole genome level not only in abnormal but also in normal tumor karyotypes. Here, we discuss the main technical features, benefits, and limitations of the above three techniques as applied to Wilms' tumor and summarize the main advances in our knowledge about the genetic changes of Wilms' tumor and their clinical relevance.

Perinatal management of infant tumors and the promise of fetal surgery

PURPOSE OF REVIEW

This review outlines the current approaches to prenatal imaging, differential diagnosis, antenatal natural history, and the available treatment options for the most commonly prenatally diagnosed malignant tumors.

RECENT FINDINGS

In-utero diagnosis of fetal tumors, although still a rare event, has become more common as prenatal imaging modalities have improved. In general, this prenatal diagnosis allows more informed prenatal counseling and better perinatal planning for potentially high-risk deliveries. There are rare indications for prenatal fetal intervention.

SUMMARY

Diagnosis of a fetal tumor should prompt referral to a specialized center. Further understanding of these rare patients will require multicenter collaboration.

Outcomes of Wilms' tumor in eastern China: 10 years of experience at a single center

PURPOSE

Wilms' tumor (WT), or nephroblastoma, is the most common renal malignancy of childhood, and its outcome varies. We aimed to retrospectively review the clinical parameters and outcomes of WT cases treated at our medical center to identify factors associated with its prognosis.

METHODS

We retrospectively reviewed WT patients who had undergone surgery and other therapy in our hospital from May 1998 to May 2008. Demographic features, mode of presentation, stage of tumor, histopathologic results, and survival rates were evaluated.

RESULTS

Our study included 67 children with WT; 38 were males and 29 were females. The mean age at onset was 39 months. Eighteen cases were diagnosed as Stage I, 23 as Stage II, 20 as Stage III, and 6 as Stage IV. Nephroureterectomy was the initial treatment in 57 children. There were 46 (68.7%) cases of favorable histology and 21 (31.3%) cases of unfavorable (anaplastic) histology. The rates of four-year event-free survival and overall survival were 78.3% and 81%, respectively. The four-year overall survival rate for cases of favorable histology (85.8%) was higher than for those with unfavorable histology (71.4%; p =.028).

CONCLUSIONS

The outcomes of WT patients in our institution were little poorer than for those of the third National Wilms Tumor Study. Advanced clinical stage at presentation, unfavorable histology, tumor rupture, relapse, delay of radiotherapy due to ignorance, and premature ending of treatment were the important factors that impacted on the outcome of WT.

Treatment and outcome of Wilms' tumour patients: an analysis of all cases registered in the UKW3 trial

BACKGROUND

The randomised findings of the UKW3 trial were that preoperative chemotherapy was associated with a more advantageous stage distribution and reduction in therapy burden versus immediate nephrectomy without compromising outcome in localised Wilms' tumour (WT). We analysed outcome in all WT registered in UKW3.

PATIENTS AND METHODS

Seven hundred and eighteen WT cases (7% anaplastic) were registered in UKW3. We assigned a treatment stage and conducted survival analysis.

RESULTS

Five-year event-free survival (EFS) and overall survival (OS) were 77.2% [95% confidence interval (CI) 73.9-80.2] and 87.5% (95% CI 84.8-89.7) after median follow-up of 9.5 years and 10.0 years, respectively. Five-year OS in localised non-anaplastic cases was 92.9% (95% CI 90.2-94.9). Anaplasia was associated with adverse outcome compared with non-anaplastic cases: 5-year EFS of 42.0% (95% CI 28.3-55.1) versus 79.8% (95% CI 76.5-82.7) and 5-year OS of 60% (95% CI 45.1-72.0) versus 89.6% (95% CI 87.0-91.7), respectively. Outcomes were similar for non-anaplastic stage I or II but significantly poorer in stage III cases than stage I. Five-year OS after relapse was 54.1% (95% CI 44.5-62.8). Forty-seven percent of non-anaplastic WT received anthracycline; 27% were treated with radiotherapy first line.

CONCLUSION

These outcomes provide a baseline for future comparisons of WT treatment approach, burden and patient outcome.

SIX1 protein expression selectively identifies blastemal elements in Wilms tumor

BACKGROUND

Wilms tumor (WT) is the most common renal neoplasm in children. Histologically, most WTs consist of three tissue elements: blastema, epithelium, and stroma. Some cases also show diffuse or focal anaplastic features. Previous studies have shown that a predominance of blastemal cells in post-chemotherapy WT specimens is associated with a poor clinical course. However, there is currently no molecular marker for blastemal cells, and risk stratification for post-nephrectomy treatment is therefore often based on clinico-histological parameters alone.

PROCEDURE

In the present study, three public gene expression microarray datasets, including 82 WTs and 8 normal fetal kidneys, were used to establish a consensus gene expression profile of WT. By bioinformatic analyses, 17 genes overexpressed in WT compared to fetal kidney were then selected for evaluation of their protein expression in WT cell lines and in the different histological components in paraffin-embedded WT tissue sections by immunofluorescence.

RESULTS

Most of the evaluated proteins were expressed in all three common histological components. A prominent exception was SIX1, being expressed predominantly in blastemal elements in 24/25 pediatric cases containing blastema. Anaplastic elements exhibited highly variable SIX1-positivity. The SIX2 protein, known to be co-expressed with SIX1 during nephrogenesis, only exhibited blastemal-predominant expression in half of the SIX2 evaluated cases.

CONCLUSIONS

Genes highly expressed in WT compared to fetal kidney are generally overexpressed in all of the three common WT tissue elements. An exception is the predominant expression of SIX1 in blastemal cells, hereby identifying this protein as a candidate marker for blastema.

Wilms' tumor- roadmaps of management

The management of Wilms' tumor emerging of the outstanding clinical trials undertaken in the developed world in the last four decades has led to excellent longterm outcomes. The scenario in developing country like India is different; late presentation with massive tumors and advanced stage, lacunae in staging, nonavailability of pediatric medical oncologists and poor follow-ups are common. A comprehensive summary of available therapeutic modalities is provided here along with clear roadmaps of management of Wilms' tumor as per Société Internationale d'Oncologie Pédiatrique (SIOP) and National Wilms' Tumor Study Group/Children's Oncology Group (NWTSG/COG) protocols in simple tabulated form.

Wilms tumor: five-year tumor-free survival on a modified SIOP protocol from an Indian university hospital

BACKGROUND AND PURPOSE

Wilms tumor is one of the most common solid malignancies of childhood. The long-term result of the surgical treatment of this tumor with adjuvant chemotherapy and radiation has been reported from many western centers. However, there is paucity of literature on the long-term outcome of treatment for this tumor from the developing world. We planned a prospective study that started in 1999 to evaluate the 5-year tumor-free survival of Wilms tumor treated on a fixed protocol from a university hospital in India.

METHODS

All consecutive children with Wilms tumor who were seen by any of the 3 investigators (2 pediatric oncologists, 1 pediatric surgeon) between 1999 and 2003 at the Advanced Pediatric Centre were included in the study. Each patient was entered into a database. Their demographic profile and events during the treatment and follow-up were recorded. This was later analyzed.

CONCLUSIONS

Seventy-five percent 5-year tumor-free survival has been achieved within the limitations of treatment in the developing world. The morbidity during therapy was 10% and the mortality 5%. This was based on the treatment of this common childhood malignancy at Chandigarh on a modified International Society of Pediatric Oncology protocol.

Urogenital tumours in childhood

The commonest urogenital tumours in childhood are Wilms tumour of the kidney and rhabdomyosarcoma in the pelvis. We review these tumours along with other primary renal tumours and less common ovarian and testicular tumours in childhood. Current clinical concepts, relevant staging investigations and imaging features are described.

Wilms tumor in a 37-year-old

Wilms’ tumor is rare in adults. Though the approach to diagnosis and treatment of adult Wilms’ tumor (AWT) is closely modeled on recommendations for childhood Wilms’ tumor, views differ on how aggressive the treatment should be. We report a case of a 37-year-old with Stage III favorable histology AWT. A radical nephrectomy was performed and the patient was due for chemotherapy. Recent advances, controversies and current recommendations in the treatment of AWT are discussed.

Treatment of Wilms tumor: a report from the Turkish Pediatric Oncology Group (TPOG)

AIM

To standardize diagnosis and treatment of childhood Wilms tumor (WT) in Turkey.

METHODS AND PATIENTS

Between 1998 and 2006, WT patients were registered from 19 centers. Patients <16 years with unilateral WT whose treatment started in first postoperative 3 weeks were included. Treatments were stage I favorable (FH) and unfavorable histology (UH) patients, VCR + Act-D; stage IIA FH, VCR + Act-D; stage IIB FH, VCR + Act-D + radiotherapy (RT); stage III-IV FH, VCR + Act-D + adriamycin (ADR) + RT; stages II-IV UH tumors, VCR + Act-D + ADR + etoposide + RT.

RESULTS

165/254 registered cases were eligible (bilateral, 5.9%) [median age 3.0 years; M/F: 0.99; 50/165 cases < or =2 years]. 9.7% cases had UH tumors. Disease stages were stage I 23.6%; IIA 36.4%; IIB 5.5%; III 22.4%; IV 12.1%. Cases >2 years had significantly more advanced disease. 1/11 cases with recurrent disease died; 2/165 had progressive disease, 2/165 had secondary cancers, and all 4 died. In all cases 4-year OS and EFS were 92.8 and 86.5%, respectively. Both OS and EFS were significantly worse in stage IV.

CONCLUSIONS

Despite problems in patient management and follow-up, treatment results were encouraging in this first national experience with a multicentric study in pediatric oncology. Revisions and modifications are planned to further improve results and minimize short- and long-term side effects.

Amplification and expression of EGFR and ERBB2 in Wilms tumor

Wilms tumor is one of the most common solid tumors in children. We evaluated expression and amplification of a number of genes and their prognostic significance in 45 patients with Wilms tumor, using tissue microarray technology. The expression of EGFR, ERBB2, MDM2, CCND1, MLH1, MSH2, TP53, and ABCB1 (alias MDR1) was studied by immunohistochemistry. Amplification of the EGFR, ERBB2, MDM2, CCND1, CTTN (previously EMS1), RAF1, MYC, FGF3 (previously INT2), WNT1, GLI1, CDK4, and NCOA3 (alias AIB1) genes was assessed by fluorescence in situ hybridization. Expression of EGFR was seen in 17 of the 45 cases (38%) but was not associated with gene amplification. The ERBB2 gene was neither overexpressed nor amplified in any case. Tissue microarray and immunohistochemistry analyses for ERBB2 in whole-tumor sections were also negative in all cases. Strong p53 reactivity was noted in blastemal cells in two cases with an unfavorable outcome. ABCB1 reactivity was seen in five cases with favorable histology and outcome. Only one case showed nuclear cyclin D1 positivity. All tumors showed MLH1 and MSH2 expression. All examined genes showed normal copy numbers. Unfavorable histology correlated with poor prognosis (P=0.03). There was no significant association between gene expression and prognosis. Overexpression of the EGFR gene in many Wilms tumor cases warrants further study to determine the therapeutic benefit of EGFR inhibitors in combination with other therapies in Wilms tumor patients.

Wilms' tumor

PURPOSE OF REVIEW

Wilms' tumor accounts for nearly 6% of all pediatric cancers and more than 95% of all kidney tumors in children. Fortunately, survival for patients with Wilms' tumor is generally excellent. This review will outline the results of prior clinical trials that have led to this excellent outcome and how information gleaned from these trials has led to the development of the current series of clinical trials for the management of children with Wilms' tumor.

RECENT FINDINGS

Tumor stage and histologic subtype have long been recognized as important prognostic factors in Wilms' tumor. More recent evidence suggests that, in certain instances, patient age, tumor size, response to therapy, and genetic abnormalities, specifically the loss of genetic material on chromosomes 1p and 16q, provide additional prognostic information. These factors have, therefore, been incorporated into a new risk stratification system that is currently being used to assign patients with Wilms' tumor to specific protocol-based therapies.

SUMMARY

Survival for patients with Wilms' tumor when considered as a whole, once less than 30%, is currently greater than 90%, with this dramatic improvement being due, in part, to the systematic manner in which the approach to therapy has evolved. Further refinement in therapy is being undertaken, with the current trials aiming to maintain the excellent survival for children being treated for Wilms' tumor, while minimizing therapy-related toxicity.

From upfront nephrectomy to preoperative chemotherapy and back: a single institution experience in the treatment of Wilms tumor

BACKGROUND

Over the past decades, 2 different approaches for the treatment of Wilms tumor have emerged: upfront nephrectomy (UN) and preoperative chemotherapy (PC), with adjuvant treatment adjusted to stage, histology, and chemotherapy response.

METHODS

In July 2005, we switched our strategy from UN to PC. This study is a retrospective review of patients treated at our institution between January 2003 and October 2007.

RESULTS

Thirty-six children (20 males) with Wilms tumor were studied. Median age was 3.45 years (range: 0.3 to 15.8 y). Nineteen patients (53%) were treated according to the International Society of Paediatric Oncology 93-01/German Pediatric Oncology Hematology, Group protocol (PC group) and 17 (47%) according to the National Wilms' Tumor Study-5 (UN group). UN group received more radiation dose and less cumulative doses of doxorubicin. The 3-year event-free survival and overall survival estimates for the whole group were 86% and 89%, respectively. Survival estimates were similar in both groups.

CONCLUSIONS

The use of PC reduced the use of radiation; however, patients treated using the SIOP 93-01/German Pediatric Oncology Hematology Group protocol received higher cumulative doses of doxorubicin; these doses were believed to be high in this young group of patients with potential for long-term toxicity. Although selecting a specific protocol for Wilms tumor is important, the development of surgical expertise and referral to specialized centers takes priority.

The prognostic relevance of preoperative transcatheter arterial chemoembolization (TACE) and PCNA/VEGF expression in patients with Wilms' tumour

BACKGROUND

Wilms' tumour is the most frequent renal tumour in children. Based on the SIOP strategy, children with Wilms' tumour may benefit from preoperative chemotherapy, but few publications address the effect of preoperative transcatheter arterial chemoembolization (TACE) on patients with Wilms' tumours. The aims of this study were to investigate the prognostic relevance of preoperative TACE followed by tumour resection, proliferating cell nuclear antigen (PCNA) and vascular endothelial growth factor (VEGF) expression in patients with Wilms' tumours.

MATERIALS AND METHODS

Two therapeutic strategies including tumour resection only and TACE, followed by tumour resection were conducted in a cohort of 44 patients with Wilms' tumours. Clinical and follow-up data was analysed. Immunohistochemistry staining was used to explore PCNA and VEGF expression in the Wilms' tumour.

RESULTS

Two years tumour-free survival of the patients in the TACE group was significantly higher than that of the patients in the control group (P < 0.001) and recurrence and cases of death within one year in the TACE group was markedly lower than that in the control group (P < 0.001). Fifty-five percent of patients in the control group were PCNA-positive vs. 4.17% of patients in the TACE group (P < 0.001). Fifty percent of patients in the control group were VEGF-positive vs. 29.17% of patients in the TACE group (P > 0.05).

CONCLUSIONS

Patients with Wilms' tumours benefited from preoperative TACE treatment. PCNA expression was significantly lower in patients in the TACE group than those in the control group. There was no significant difference on VEGF expression between the patients in TACE and control groups.

B7-H1 expression in Wilms tumor: correlation with tumor biology and disease recurrence

PURPOSE

Despite tremendous gains in improving prognosis, 10% of patients with Wilms tumor will ultimately experience disease recurrence. The identification of novel prognostic markers and tumor associated targets for patients at risk could enable clinicians to treat recurrences more aggressively and, thus, optimize outcomes. We have previously shown that tumor expression of the T cell coregulatory ligand B7-H1 portends a poor prognosis for adults with renal cell carcinoma and represents a promising target to improve therapy. We hypothesize that this finding may be true for Wilms tumor.

MATERIALS AND METHODS

We identified 81 patients with Wilms tumor treated at 1 institution between 1968 and 2004. Histopathological features, including Wilms tumor B7-H1 expression, were correlated with clinical observations and outcome.

RESULTS

Tumor recurrences were noted in 22% of patients with Wilms tumor and 14% died. B7-H1 was expressed in 11 tumors (14%) and was more likely to occur in anaplastic Wilms tumor (p = 0.03). Tumor B7-H1 expression was associated with a 2.7-fold increased risk of recurrence, although this difference did not achieve statistical significance (p = 0.06). However, in favorable histology tumors B7-H1 expression was associated with a 3.7-fold increased risk of recurrence (p = 0.03).

CONCLUSIONS

B7-H1 is expressed by Wilms tumor, correlates with tumor biology and is associated with an increased risk of recurrence in patients with favorable histology tumors. B7-H1 may prove useful in identifying high risk patients who could benefit from more aggressive initial treatment regimens, and may represent a promising therapeutic target. Multi-institutional studies to elucidate the role of B7-H1 in the treatment of Wilms tumor are warranted.

Bilateral disease and new trends in Wilms tumour

Wilms tumour is a great therapeutic success story within paediatric oncology; its prognosis is excellent. Although mainly sporadic, occurring in otherwise well children, it occurs in a small number of genetically predisposed children. Thus regular surveillance imaging is performed in predisposed children in parts of the USA and Europe. The risks and benefits of surveillance are unclear, as the existing ad-hoc surveillance protocols are lacking in consistency of practice and equity of provision. We present guidelines for Wilms tumour surveillance based on a review of current practice and available evidence, outlined by a multidisciplinary working group in the UK. Wilms tumours are bilateral in 4-13% of affected children. Bilateral synchronous nephroblastomas are observed in 5% of affected children and are usually associated with the presence of nephrogenic rests, congenital malformations and predisposing syndromes. The major challenge in bilateral disease is to achieve a cure and at the same time to preserve sufficient functional renal tissue for normal growth and development. The association among Wilms tumour, nephrogenic rests and nephroblastomatosis makes detection and characterization of renal lesions with imaging extremely important. We discuss the relative strengths and weaknesses of the different modalities used for diagnosis and follow-up in bilateral renal disease. We also discuss newly emerging diagnostic imaging tests such as (18)F-fluorodeoxyglucose positron emission tomography (FDG-PET). This technique, when fused with CT (PET-CT), allows accelerated metabolic activity to be accurately anatomically localised and so is potentially useful for staging, assessment of treatment response, and for surgical and radiotherapy planning. In addition, quantitative MRI techniques have been proved to be valuable in intracranial tumours, but no such role has been validated in abdominal disease. Diffusion-weighted imaging with calculation of ADC maps is feasible in abdominal tumours, and our own preliminary data suggest that tissue cellularity is an important determinant of ADC value, which might help in terms of early prediction of therapy response.

Surveillance for Wilms tumour in at-risk children: pragmatic recommendations for best practice

BACKGROUND

Most Wilms tumours occur in otherwise healthy children, but a small proportion occur in children with genetic syndromes associated with increased risks of Wilms tumour. Surveillance for Wilms tumour has become widespread, despite a lack of clarity about which children are at increased risk of these tumours and limited evidence of the efficacy of screening or guidance as to how screening should be implemented.

METHODS

The available literature was reviewed.

RESULTS

The potential risks and benefits of Wilms tumour surveillance are finely balanced and there is no clear evidence that screening reduces mortality or morbidity. Prospective evidence-based data on the efficacy of Wilms tumour screening would be difficult and costly to generate and are unlikely to become available in the foreseeable future.

CONCLUSIONS

The following pragmatic recommendations have been formulated for Wilms tumour surveillance in children at risk, based on our review: (1) Surveillance should be offered to children at >5% risk of Wilms tumour. (2) Surveillance should only be offered after review by a clinical geneticist. (3) Surveillance should be carried out by renal ultrasonography every 3-4 months. (4) Surveillance should continue until 5 years of age in all conditions except Beckwith-Wiedemann syndrome, Simpson-Golabi-Behmel syndrome and some familial Wilms tumour pedigrees where it should continue until 7 years. (5) Surveillance can be undertaken at a local centre, but should be carried out by someone with experience in paediatric ultrasonography. (6) Screen-detected lesions should be managed at a specialist centre.

Expression of cyclooxygenase-2 in Wilms tumor: immunohistochemical study using tissue microarray methodology

PURPOSE

Cyclooxygenase-2, a key enzyme in prostaglandin biosynthesis, has been shown to be involved in the modulation of cell growth, inflammation and apoptosis. Its involvement in the development of several human neoplasms has also been documented as well as the significant antitumor effects of its inhibitors. To our knowledge cyclooxygenase-2 expression in Wilms tumor has not been studied.

MATERIALS AND METHODS

A tissue microarray multitissue block was prepared from 14 samples of Wilms tumor, each from a different patient, from xenografts derived thereof, and from normal human lung, liver, renal cortex and medulla tissues as controls. Each sample was represented in the block by 3 or 4 cores 0.6 mm in diameter. After serial slicing to 4 mum the histological slides were stained with hematoxylin and eosin, and immunostained with anti-cyclooxygenase-2 antibodies. Immunostaining was graded semiquantitatively according to the percent of stained cells with the cytoplasmic pattern of staining and according to staining intensity.

RESULTS

All authentic human pathological samples except 1 anaplastic Wilms tumor as well as Wilms tumor xenografts expressed cyclooxygenase-2 in all Wilms tumor cellular components except the stroma. Expression was also observed in Wilms tumor lung metastasis and in tumors that overgrew chemotherapy. In comparison, cyclooxygenase-2 expression in normal kidneys was less prominent than in Wilms tumor samples and it was confined to the tubular epithelium in the cortex and medulla.

CONCLUSIONS

Cyclooxygenase-2 expression is characteristic of all nonanaplastic Wilms tumors at all stages. It is similar to the previously observed pan-expression of ErbB2 receptors in these tumors. The potential therapeutic role of cyclooxygenase-2 inhibitors should be evaluated for Wilms tumor.

The challenge of nephroblastoma in a developing country

BACKGROUND

Advances in paediatric oncology has tremendously improved the outcome in children with nephroblastoma. In most developing countries, however, the survival rate is still very low.

OBJECTIVE

To study the outcome and the impediments to the management of nephroblastoma in Southeast Nigeria.

METHODS

Analysis of 42 children managed for nephroblastoma over a 10-year period (January 1995-December 2004) at the University of Nigeria Teaching Hospital, Enugu, Nigeria is made. Diagnosis was based on clinical, radiologic and histologic evaluation.

RESULTS

The peak age incidence was 2-5 years with a male:female ratio of 1.1:1. Abdominal mass was the main presentation in all the children. Treatment consisted of nephroureterectomy followed by adjuvant chemotherapy with Vincristine, Actinomycin D and Cyclophosphamide. Adriamycin was added for metastatic disease. Twenty-two children (52.3%) had stage III disease, 13 (31.0%) had stage IV, while the remaining seven (16.7%) children had stage II. Stage I disease was not encountered. Seven children had inoperable tumor requiring pre-operative chemotherapy. While 25 children were available for evaluation, 17 were lost to follow up. Four children died of complications of treatment, while 11 relapsed with poor outcome. With a mean follow up of 21 months, the 5-year survival rate is 40%.

CONCLUSION

Morbidity and mortality with nephroblastoma is high in our environment. Late presentation, poverty, ignorance and poor compliance to treatment constitute a great challenge to the paediatric oncologist in a developing country. Solutions may lie in improving health funding and health information in the health care delivery system. Free health care for children with malignancy is advocated. Collaboration with institutions in the privileged parts of the world may help.

Syndromes and constitutional chromosomal abnormalities associated with Wilms tumour

Wilms tumour has been reported in association with over 50 different clinical conditions and several abnormal constitutional karyotypes. Conclusive evidence of an increased risk of Wilms tumour exists for only a minority of these conditions, including WT1 associated syndromes, familial Wilms tumour, and certain overgrowth conditions such as Beckwith-Wiedemann syndrome. In many reported conditions the rare co-occurrence of Wilms tumour is probably due to chance. However, for several conditions the available evidence cannot either confirm or exclude an increased risk, usually because of the rarity of the syndrome. In addition, emerging evidence suggests that an increased risk of Wilms tumour occurs only in a subset of individuals for some syndromes. The complex clinical and molecular heterogeneity of disorders associated with Wilms tumour, together with the apparent absence of functional links between most of the known predisposition genes, suggests that abrogation of a variety of pathways can promote Wilms tumorigenesis.