Characteristics and outcome of children with Beckwith-Wiedemann syndrome and Wilms' tumor: a report from the National Wilms Tumor Study Group

Implications of an Underlying Beckwith-Wiedemann Syndrome for Wilms Tumor Treatment Strategies

Beckwith-Wiedemann Syndrome (BWS) is a pediatric overgrowth disorder involving a predisposition to embryonal tumors. Most of the tumors associated with BWS occur in the first 8-10 years of life, and the most common is Wilms tumor (WT). BWS clinical heterogeneity includes subtle overgrowth features or even silent phenotypes, and WT may be the presenting symptom of BWS. WT in BWS individuals exhibit distinct characteristics from those of sporadic WT, and the management of these patients needs a peculiar approach. The most important feature is a higher risk of developing bilateral disease at some time in the course of the illness (synchronous bilateral disease at diagnosis or metachronous recurrence after initial presentation with unilateral disease). Accordingly, neoadjuvant chemotherapy is the recommended approach also for BWS patients with unilateral WT to facilitate nephron-sparing surgical approaches. This review emphasizes the importance of early BWS recognition, particularly if a WT has already occurred, as this will result in an urgent consideration of first-line cancer therapy.

Concurrent Hepatoblastoma and Wilms Tumor Leading to Diagnosis of Beckwith-Wiedemann Syndrome

Beckwith-Wiedemann syndrome (BWS) is an epigenetic overgrowth disorder and cancer predisposition syndrome caused by imprinting defects of chromosome 11p15.5-11p15.4. BWS should be considered in children with atypical presentations of embryonal tumors regardless of clinical phenotype. Risk of malignancy correlates with specific molecular subgroups of BWS making molecular subclassification important for appropriate cancer screening. We report the first case of concurrent embryonal tumors in a phenotypically normal child, leading to the diagnosis of BWS with paternal uniparental disomy and describe the molecular classification of BWS as it relates to malignancy risk, along with approach to management.

Molecular Basis of Beckwith–Wiedemann Syndrome Spectrum with Associated Tumors and Consequences for Clinical Practice

Simple Summary

Beckwith–Wiedemann syndrome (BWS, OMIM 130650) is an inborn overgrowth disorder caused by molecular alterations in chromosome 11p15.5. These molecular changes affect so-called imprinted genes, i.e., genes which underlie a complex regulation which is linked to the parental origin of the gene copy. Thus, either the maternal gene copy is expressed or the paternal, but this balanced regulation is prone to disturbances. In fact, different types of molecular variants have been identified in BWS, resulting in a variable phenotype; thus, it was consented that the syndromic entity was extended to the Beckwith–Wiedemann spectrum (BWSp). Some molecular subgroups of BWSp are associated with an increased embryonic tumor risk and have different likelihoods for specific tumors. Therefore, the precise determination of the molecular subgroup is needed for precise monitoring and treatment, but the molecular diagnostic procedure has several limitations and challenges which have to be considered.

Abstract

Beckwith–Wiedemann syndrome (BWS, OMIM 130650) is a congenital imprinting condition with a heterogenous clinical presentation of overgrowth and an increased childhood cancer risk (mainly nephroblastoma, hepatoblastoma or neuroblastoma). Due to the varying clinical presentation encompassing classical, clinical BWS without a molecular diagnosis and BWS-related phenotypes with an 11p15.5 molecular anomaly, the syndromic entity was extended to the Beckwith–Wiedemann spectrum (BWSp). The tumor risk of up to 30% depends on the molecular subtype of BWSp with causative genetic or epigenetic alterations in the chromosomal region 11p15.5. The molecular diagnosis of BWSp can be challenging for several reasons, including the range of causative molecular mechanisms which are frequently mosaic. The molecular basis of tumor formation appears to relate to stalled cellular differentiation in certain organs that predisposes persisting embryonic cells to accumulate additional molecular defects, which then results in a range of embryonal tumors. The molecular subtype of BWSp not only influences the overall risk of neoplasia, but also the likelihood of specific embryonal tumors.

Lateralized and Segmental Overgrowth in Children

Congenital disorders of lateralized or segmental overgrowth (LO) are heterogeneous conditions with increased tissue growth in a body region. LO can affect every region, be localized or extensive, involve one or several embryonic tissues, showing variable severity, from mild forms with minor body asymmetry to severe ones with progressive tissue growth and related relevant complications. Recently, next-generation sequencing approaches have increased the knowledge on the molecular defects in LO, allowing classifying them based on the deranged cellular signaling pathway. LO is caused by either genetic or epigenetic somatic anomalies affecting cell proliferation. Most LOs are classifiable in the Beckwith-Wiedemann spectrum (BWSp), PI3KCA/AKT-related overgrowth spectrum (PROS/AROS), mosaic RASopathies, PTEN Hamartoma Tumor Syndrome, mosaic activating variants in angiogenesis pathways, and isolated LO (ILO). These disorders overlap over common phenotypes, making their appraisal and distinction challenging. The latter is crucial, as specific management strategies are key: some LO is associated with increased cancer risk making imperative tumor screening since childhood. Interestingly, some LO shares molecular mechanisms with cancer: recent advances in tumor biological pathway druggability and growth downregulation offer new avenues for the treatment of the most severe and complicated LO.

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

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

Pediatric onco-nephrology: time to spread the word : Part I: early kidney involvement in children with malignancy

Onco-nephrology has been a growing field within the adult nephrology scope of practice. Even though pediatric nephrologists have been increasingly involved in the care of children with different forms of malignancy, there has not been an emphasis on developing special expertise in this area. The fast pace of discovery in this field, including the development of new therapy protocols with their own kidney side effects and the introduction of the CD19-targeted chimeric antigen receptor T cell (CAR-T) therapy, has introduced new challenges for general pediatric nephrologists because of the unique effects of these treatments on the kidney. Moreover, with the improved outcomes in children receiving cancer therapy come an increased number of survivors at risk for chronic kidney disease related to both their cancer diagnosis and therapy. Therefore, it is time for pediatric onco-nephrology to take its spot on the expanding subspecialties map in pediatric nephrology.

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

Simple Summary

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

Abstract

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

Results of Treatment for Patients With Multicentric or Bilaterally Predisposed Unilateral Wilms Tumor (AREN0534): A report from the Children's Oncology Group

BACKGROUND

A primary objective of Children's Oncology Group study AREN0534 (Treatment for Patients With Multicentric or Bilaterally Predisposed, Unilateral Wilms Tumor) was to facilitate partial nephrectomy in 25% of children with bilaterally predisposed unilateral tumors (Wilms tumor/aniridia/genitourinary anomalies/range of developmental delays [WAGR] syndrome; and multifocal and overgrowth syndromes). The purpose of this prospective study was to achieve excellent event-free survival (EFS) and overall survival (OS) while preserving renal tissue through preoperative chemotherapy, completing definitive surgery by 12 weeks from diagnosis, and modifying postoperative chemotherapy based on histologic response.

METHODS

The treating institution identified whether a predisposition syndrome existed. Patients underwent a central review of imaging studies through the biology and classification study AREN03B2 and then were eligible to enroll on AREN0534. Patients were treated with induction chemotherapy determined by localized or metastatic disease on imaging (and histology if a biopsy had been undertaken). Surgery was based on radiographic response at 6 or 12 weeks. Further chemotherapy was determined by histology. Patients who had stage III or IV disease with favorable histology received radiotherapy as well as those who had stage I through IV anaplasia.

RESULTS

In total, 34 patients were evaluable, including 13 males and 21 females with a mean age at diagnosis of 2.79 years (range, 0.49-8.78 years). The median follow-up was 4.49 years (range, 1.67-8.01 years). The underlying diagnosis included Beckwith-Wiedemann syndrome in 9 patients, hemihypertrophy in 9 patients, multicentric tumors in 10 patients, WAGR syndrome in 2 patients, a solitary kidney in 2 patients, Denys-Drash syndrome in 1 patient, and Simpson-Golabi-Behmel syndrome in 1 patient. The 4-year EFS and OS rates were 94% (95% CI, 85.2%-100%) and 100%, respectively. Two patients relapsed (1 tumor bed, 1 abdomen), and none had disease progression during induction. According to Response Evaluation Criteria in Solid Tumor 1.1 criteria, radiographic responses included a complete response in 2 patients, a partial response in 21 patients, stable disease in 11 patients, and progressive disease in 0 patients. Posttherapy histologic classification was low-risk in 13 patients (including the 2 complete responders), intermediate-risk in 15 patients, and high-risk in 6 patients (1 focal anaplasia and 5 blastemal subtype). Prenephrectomy chemotherapy facilitated renal preservation in 22 of 34 patients (65%).

CONCLUSIONS

A standardized approach of preoperative chemotherapy, surgical resection within 12 weeks, and histology-based postoperative chemotherapy results in excellent EFS, OS, and preservation of renal parenchyma.

Imaging surveillance for children with predisposition to renal tumors

Effective surveillance is necessary for early detection of tumors in children with cancer predisposition syndromes. Instituting a surveillance regimen in children comes with practical challenges that include determining imaging modality and timing, and considering cost efficiency, accessibility, and the significant consequences of false-positive and false-negative results. To address these challenges, the American Association for Cancer Research has recently published consensus recommendations that focus on surveillance of cancer predisposition syndromes in children. This review condenses the imaging surveillance recommendations for syndromes that carry a predisposition to renal tumors in childhood, and includes summaries of the predisposition syndromes and discussion of considerations of available imaging modalities.

Origins of DNA methylation defects in Wilms tumors

Wilms tumor is an embryonic renal cancer that typically presents in early childhood and accounts for 7% of all paediatric cancers. Different genetic alterations have been described in this malignancy, however, only a few of them are associated with a majority of Wilms tumors. Alterations in DNA methylation, in contrast, are frequent molecular defects observed in most cases of Wilms tumors. How these epimutations are established in this tumor is not yet completely clear. The recent identification of the molecular actors required for the epigenetic reprogramming during embryogenesis suggests novel possible mechanisms responsible for the DNA methylation defects in Wilms tumor. Here, we provide an overview of the DNA methylation alterations observed in this malignancy and discuss the distinct molecular mechanisms by which these epimutations can arise.

Tumor risk and surveillance for children with hereditary disorders affecting growth

PURPOSE OF REVIEW

Hereditary disorders affecting growth (both overgrowth and growth retardation) are frequently associated with heightened risk of neoplastic disease. This review summarizes the tumor spectra associated with these conditions and identifies disease-specific screening approaches.

RECENT FINDINGS

An understanding of the molecular events underlying many of these growth disorders has evolved significantly over the past several years. Recognition of genotype-phenotype associations, in many cases, informs the cancer risk profile. Additionally, accumulating data suggest a benefit of rational presymptomatic surveillance for at-risk individuals, with a reduction in tumor-associated morbidity. Recent clinical practice recommendations have established risk-driven paradigms for tumor surveillance in the context of hereditary tumor predisposition syndromes, including those affecting growth.

SUMMARY

Clinicians caring for children with growth disorders should be aware of syndromic associations and the associated cancer risks. Knowledge of tumor spectra and recommended surveillance strategies may facilitate tumor diagnosis at an early stage and reduce morbidity of the disease and associated treatments.

Diagnosis and Management of Beckwith-Wiedemann Syndrome

Beckwith-Wiedemann syndrome (BWS) is a human genomic imprinting disorder that presents with a wide spectrum of clinical features including overgrowth, abdominal wall defects, macroglossia, neonatal hypoglycemia, and predisposition to embryonal tumors. It is associated with genetic and epigenetic changes on the chromosome 11p15 region, which includes two imprinting control regions. Here we review strategies for diagnosing and managing BWS and delineate commonly used genetic tests to establish a molecular diagnosis of BWS. Recommended first-line testing assesses DNA methylation and copy number variation of the BWS region. Tissue mosaicism can occur in patients with BWS, posing a challenge for genetic testing, and a negative test result does not exclude a diagnosis of BWS. Further testing should analyze additional tissue samples or employ techniques with higher diagnostic yield. Identifying the BWS molecular subtype is valuable for coordinating patient care because of the (epi)genotype-phenotype correlations, including different risks and types of embryonal tumors.

Fetal programming and Wilms tumor

BACKGROUND

The "fetal programming" hypothesis has been evaluated in many adult diseases including cancer, but not for Wilms tumor. Wilms tumor has been related to high birthweight, but little is known about other growth metrics such as a baby's birth length, ponderal index, or placenta size, which can shed additional light on growth patterns.

METHODS

Cases of Wilms tumor (N = 217) were taken from the Danish Cancer Registry, and controls (N = 4340) were randomly selected from the Population Register and matched to cases by sex and age. Linkage to the Medical Births Registry provided information on gestational factors and fetal growth measurements, while linkage to the Patient Register provided information on maternal and child health conditions.

RESULTS

Despite having typically normal to higher birthweights, Wilms tumor cases had smaller placentas (≤540 g; odds ratio (OR) = 4.24; 95% confidence interval (CI), 1.84-9.78) and a lower placenta-to-birthweight ratio (OR = 1.81; 95% CI, 1.17-2.82, per 1 SD decrease). Small placentas were more common among Wilms cases without congenital anomalies (OR = 6.43; 95% CI, 1.95-21.21). Wilms tumor cases had a higher prevalence of high birthweight (>4000 g; OR = 1.57; 95% CI, 1.11-2.22), birth length 55 cm or longer (OR = 1.74; 95% CI, 1.09-2.78), and being large for gestational age (OR = 1.79; 95% CI, 1.08-2.96).

CONCLUSIONS

Our study corroborates earlier studies showing associations with high birthweight and suggests associations between Wilms tumor and decreased placental size and low placenta-to-birthweight ratio.

Diseases Predisposing to Adrenocortical Malignancy (Li-Fraumeni Syndrome, Beckwith-Wiedemann Syndrome, and Carney Complex)

Adrenocortical malignancies can occur in the context of several tumor predisposition syndromes.The Carney complex (CNC) is responsible for the majority of primary pigmented nodular adrenal diseases and is more rarely associated with adrenocortical carcinoma (ACC). Other core manifestations of CNC include cardiac and cutaneous myxomas, lentiginosis, somatotroph pituitary adenomas, Sertoli tumors, melanocytic schwannoma, and thyroid, breast, and bone tumors. CNC is mostly due to germline inactivating mutations of PRKAR1A.The majority of childhood ACC are related to genetic predisposition. The Beckwith-Wiedemann syndrome (BWS) is an overgrowth and tumor predisposition syndrome due to genetic or epigenetic alterations at the 11p15 locus. Classical tumor spectrum of BWS includes embryonal tumors and childhood ACC. The Li-Fraumeni syndrome (LFS) is a devastating tumor predisposition syndrome, due to germline inactivating mutations of TP53, and characterized by a high, various, and early-onset cancer risk. LFS spectrum includes premenopausal breast cancer, soft-tissue sarcoma, osteosarcoma, central nervous system tumor, and ACC, accounting for 50-80% of pediatric cases. Finally, germline predisposition affects up to 10% of adult ACC patients, mostly in part of LFS and Lynch syndrome.This chapter focuses on the diagnosis, screening, and management of adrenal tumors in part of these tumor predisposition syndromes.

Bilateral Wilms Tumor: A Surgical Perspective

Historically, the management of bilateral Wilms tumor (BWT) was non-standardized and suffered from instances of prolonged chemotherapy and inconsistent surgical management which resulted in suboptimal renal and oncologic outcomes. Because of the risk of end-stage renal disease associated with the management of BWT, neoadjuvant chemotherapy and nephron-sparing surgery have been adopted as the guiding management principles. This management strategy balances acceptable oncologic outcomes against the risk of end-stage renal disease. A recent multi-institutional Children’s Oncology Group study (AREN0534) has confirmed the benefits of standardized 3-drug neoadjuvant chemotherapy and the utilization of nephron-sparing surgery in BWT patients; however, less than 50% of patients underwent bilateral nephron-sparing surgery. The coordination of neoadjuvant chemotherapy and the timing and implementation of bilateral nephron-sparing surgery are features of BWT management that require collaboration between oncologists and surgeons. This review discusses the surgical management strategy in the context of BWT disease biology, with an emphasis on timepoints during therapy at which surgical decision making can greatly impact this disease and minimize long-term toxicities.

Benign Multicystic Peritoneal Mesothelioma in a Male Patient with Previous Wilms' Tumor: A Case Report and Review of the Literature

Benign multicystic peritoneal mesothelioma (BMPM) is a rare condition, more common in females of reproductive age, which arises from the peritoneal mesothelium. A 33-year-old male presented to our unit with abdominal pain and constipation. His past medical history included a previous unilateral nephrectomy for Wilms' tumor and the previous incidental finding of some intra-abdominal cystic formations at the level of the mesentery. After performing a CT scan, an exploratory laparotomy was done and a voluminous cystic mesenteric mass, composed of 3 confluent formations, was observed. Some other similar but significantly smaller lesions were found. An en bloc resection of the mesenteric mass together with the corresponding intestinal loops, an appendicectomy, and some peritoneal biopsies were performed. The postoperative period was complicated by a peritonitis due to dehiscence of the intestinal anastomosis, which required another operation, and a delayed return of normal bowel function, which was resolved through prokinetic therapy. Through histological examination, a BMPM was diagnosed. At 8 months of follow-up, the patient is free of symptoms. BMPM exact etiopathogenesis still remains uncertain. Given his high recurrence rate, a long-term follow-up is recommended.

Expert consensus document: Clinical and molecular diagnosis, screening and management of Beckwith-Wiedemann syndrome: an international consensus statement

Beckwith-Wiedemann syndrome (BWS), a human genomic imprinting disorder, is characterized by phenotypic variability that might include overgrowth, macroglossia, abdominal wall defects, neonatal hypoglycaemia, lateralized overgrowth and predisposition to embryonal tumours. Delineation of the molecular defects within the imprinted 11p15.5 region can predict familial recurrence risks and the risk (and type) of embryonal tumour. Despite recent advances in knowledge, there is marked heterogeneity in clinical diagnostic criteria and care. As detailed in this Consensus Statement, an international consensus group agreed upon 72 recommendations for the clinical and molecular diagnosis and management of BWS, including comprehensive protocols for the molecular investigation, care and treatment of patients from the prenatal period to adulthood. The consensus recommendations apply to patients with Beckwith-Wiedemann spectrum (BWSp), covering classical BWS without a molecular diagnosis and BWS-related phenotypes with an 11p15.5 molecular anomaly. Although the consensus group recommends a tumour surveillance programme targeted by molecular subgroups, surveillance might differ according to the local health-care system (for example, in the United States), and the results of targeted and universal surveillance should be evaluated prospectively. International collaboration, including a prospective audit of the results of implementing these consensus recommendations, is required to expand the evidence base for the design of optimum care pathways.

Pediatric Cancer Predisposition and Surveillance: An Overview, and a Tribute to Alfred G. Knudson Jr

The prevalence of childhood cancer attributable to genetic predisposition was generally considered very low. However, recent reports suggest that at least 10% of pediatric cancer patients harbor a germline mutation in a cancer predisposition gene. Although some of these children will have a family history suggestive of a cancer predisposition syndrome, many others will not. Evidence from recent pediatric studies suggests that surveillance and early detection of cancer in individuals carrying a germline cancer predisposing mutation may result in improved outcomes. However, there is a lack of consistency in the design of cancer surveillance regimens across centers both nationally and internationally. To standardize approaches, the Pediatric Cancer Working Group of the American Association for Cancer Research (AACR) convened a workshop, during which consensus screening recommendations for children with the most common cancer predisposition syndromes were developed. In general, we considered a 5% or greater chance of developing a childhood cancer to be a reasonable threshold to recommend screening. Conditions for which the cancer risk was between 1% to 5% were addressed individually. In a series of manuscripts accompanying this article, we provide recommendations for surveillance, focusing on when to initiate and/or discontinue specific screening measures, which modalities to use, and the frequency of screening. Points of controversy are also reviewed. We present the outcome of our deliberations on consensus screening recommendations for specific disorders in 18 position articles as Open Access publications, which are freely available on an AACR-managed website. Clin Cancer Res; 23(11); e1-e5. ©2017 AACRSee all articles in the online-only CCR Pediatric Oncology Series.

Sonographic screening for Wilms tumor in children with CLOVES syndrome

BACKGROUND

CLOVES syndrome is associated with somatic mosaic PIK3CA mutations and characterized by congenital lipomatous overgrowth, vascular malformations, epidermal nevi, and skeletal anomalies. Wilms tumor (WT) is a malignant embryonal renal neoplasm associated with hemihypertrophy and certain overgrowth disorders. After identifying WT in a child with CLOVES, we questioned whether ultrasonographic screening was necessary in these patients.

METHODS

We retrospectively reviewed patients with CLOVES syndrome in our Vascular Anomalies Center at Boston Children's Hospital between 1998 and 2016 to identify those who developed WT. A PubMed literature search was also conducted to find other patients with both conditions.

RESULTS

A total of 122 patients with CLOVES syndrome were found in our database (mean age 7.7 years, range 0-53 years). Four patients developed WT; all were diagnosed by 2 years of age. The incidence of WT in our CLOVES patient population (3.3%) was significantly greater than the incidence of WT in the general population (1/10,000) (P < 0.001). Four additional patients with WT and CLOVES syndrome were identified in our literature review.

CONCLUSION

Patients with CLOVES syndrome have an increased risk of WT. Given the benefits of early detection and treatment, children with CLOVES syndrome should be considered for quarterly abdominal ultrasonography until age 7 years. Screening may be most beneficial for patients under 3 years of age.

Wilms tumour in Beckwith-Wiedemann Syndrome and loss of methylation at imprinting centre 2: revisiting tumour surveillance guidelines

Beckwith-Wiedemann Syndrome (BWS) is an overgrowth syndrome caused by a variety of molecular changes on chromosome 11p15.5. Children with BWS have a significant risk of developing Wilms tumours with the degree of risk being dependent on the underlying molecular mechanism. In particular, only a relatively small number of children with loss of methylation at the centromeric imprinting centre (IC2) were reported to have developed Wilms tumour. Discontinuation of tumour surveillance for children with BWS and loss of methylation at IC2 has been proposed in several recent publications. We report here three children with BWS reported to have loss of methylation at IC2 on clinical testing who developed Wilms tumour or precursor lesions. Using multiple molecular approaches and multiple tissues, we reclassified one of these cases to paternal uniparental disomy for chromosome 11p15.5. These cases highlight the current challenges in definitively assigning tumour risk based on molecular classification in BWS. The confirmed cases of loss of methylation at IC2 also suggest that the risk of Wilms tumour in this population is not as low as previously thought. Therefore, we recommend that for now, all children with a clinical or molecular diagnosis of BWS be screened for Wilms tumour by abdominal ultrasonography until the age of eight years regardless of the molecular classification.

Bilateral Wilms tumour: a review of clinical and molecular features

Wilms tumour (WT) is the most common paediatric kidney cancer and affects approximately one in 10 000 children. The tumour is associated with undifferentiated embryonic lesions called nephrogenic rests (NRs) or, when diffuse, nephroblastomatosis. WT or NRs can occur in both kidneys, termed bilateral disease, found in only 5-8% of cases. Management of bilateral WT presents a major clinical challenge in terms of maximising survival, preserving renal function and understanding underlying genetic risk. In this review, we compile clinical data from 545 published cases of bilateral WT and discuss recent progress in understanding the molecular basis of bilateral WT and its associated precursor NRs in the context of the latest radiological, surgical and epidemiological features.

Cancer Risk in Beckwith-Wiedemann Syndrome: A Systematic Review and Meta-Analysis Outlining a Novel (Epi)Genotype Specific Histotype Targeted Screening Protocol

OBJECTIVE

To compare tumor risk in the 4 Beckwith-Wiedemann syndrome (BWS) molecular subgroups: Imprinting Control Region 1 Gain of Methylation (ICR1-GoM), Imprinting Control Region 2 Loss of Methylation (ICR2-LoM), Chromosome 11p15 Paternal Uniparental Disomy (UPD), and Cyclin-Dependent Kinase Inhibitor 1C gene (CDKN1C) mutation.

STUDY DESIGN

Studies on BWS and tumor development published between 2000 and 2015 providing (epi)genotype-cancer correlations with histotype data were reviewed and meta-analysed with cancer histotypes as measured outcome and (epi)genotype as exposure.

RESULTS

A total of 1370 patients with BWS were included: 102 developed neoplasms (7.4%). Tumor prevalence was 2.5% in ICR2-LoM, 13.8% in UPD, 22.8% in ICR1-GoM, and 8.6% in patients with CDKN1C mutations. Cancer ORs were 12.8 in ICR1-GoM, 6.5 in UPD, and 2.9 in patients with CDKN1C mutations compared with patients with ICR2-LoM. Wilms tumor was associated with ICR1-GoM (OR 68.3) and UPD (OR 13.2). UPD also was associated with hepatoblastoma (OR 5.2) and adrenal carcinoma (OR 7.0), and CDKN1C mutations with neuroblastic tumors (OR 7.2).

CONCLUSION

Cancer screening in BWS could be differentiated on the basis of (epi)genotype and target specific histotypes. Patients with ICR1-GoM and UPD should undergo renal ultrasonography scanning, given their risk of Wilms tumor. Alpha feto protein monitoring for heptaoblastoma is suggested in patients with UPD. Adrenal carcinoma may deserve screening in patients with UPD. Patients with CDKN1C mutations may deserve neuroblastoma screening based on urinary markers and ultrasonography scanning. Finally, screening appears questionable in cases of ICR2-LoM, given low tumor risk.

Is Nephron Sparing Surgery Justified in Wilms Tumor With Beckwith-Wiedemann Syndrome or Isolated Hemihypertrophy?

BACKGROUND

Patients with Beckwith-Wiedemann syndrome (BWS) or isolated hemihypertrophy (HH) treated for a Wilms tumor (WT) carry an increased risk of developing metachronous lesion. There are no guidelines on precise indications for nephron sparing surgery (NSS) in unilateral WT (UWT). The objective of this retrospective study was to delineate the indications of NSS in patients with BWS/HH treated for WT and to evaluate their outcome.

PROCEDURE

All cases of BWS/HH treated for a WT according to SIOP protocols from 1980 to 2013 were reviewed. Patients were divided into two groups (G): isolated UWT (G1) and bilateral lesions (G2) with two subgroups: bilateral tumors suspected of malignancy (G2a), and unilateral tumor suspected of malignancy with contralateral nephroblastomatosis (G2b).

RESULTS

Forty-six patients were included (34 G1, three G2a, and nine G2b). Nine NSS and 25 total nephrectomies (TN) were performed in G1, two bilateral NSS and one NSS with contralateral TN in G2a, and eight NSS and one TN in G2b. The 3-year event-free survival was 92.3% (95% CI [77.9-97.5%]). One death occurred after a local relapse following a TN for a stage III stromal WT (G1) and another after a combined local and distant relapse following a NSS for a stage I diffuse anaplastic WT (G2b). There were two metachronous WT (4%), 3 years after a TN (G1) and 12 years after a NSS (G2b).

CONCLUSIONS

NSS is recommended in bilateral WT and may be an option in selected UWT patients with BWS/HH because it was not associated with an increased risk of local relapse.

Recommendations of the Scientific Committee of the Italian Beckwith-Wiedemann Syndrome Association on the diagnosis, management and follow-up of the syndrome

Beckwith-Wiedemann syndrome (BWS) is the most common (epi)genetic overgrowth-cancer predisposition disorder. Given the absence of consensual recommendations or international guidelines, the Scientific Committee of the Italian BWS Association (www.aibws.org) proposed these recommendations for the diagnosis, molecular testing, clinical management, follow-up and tumor surveillance of patients with BWS. The recommendations are intended to allow a timely and appropriate diagnosis of the disorder, to assist patients and their families, to provide clinicians and caregivers optimal strategies for an adequate and satisfactory care, aiming also at standardizing clinical practice as a national uniform approach. They also highlight the direction of future research studies in this setting. With recent advances in understanding the disease (epi)genetic mechanisms and in describing large cohorts of BWS patients, the natural history of the disease will be dissected. In the era of personalized medicine, the emergence of specific (epi)genotype-phenotype correlations in BWS will likely lead to differentiated follow-up approaches for the molecular subgroups, to the development of novel tools to evaluate the likelihood of cancer development and to the refinement and optimization of current tumor screening strategies.

CONCLUSIONS

In this article, we provide the first comprehensive recommendations on the complex management of patients with Beckwith-Wiedemann syndrome.

Renal function in patients with Wilms tumor

Survival in patients with Wilms tumor (WT) is excellent compared with other pediatric malignancies and adult renal tumors. Treatment-related long-term morbidity and mortality in WT survivors is an area of increasing concern. Renal dysfunction is an example of one of the most feared long-term issues observed in these survivors. Direct toxicity from chemotherapy and radiation as well as direct nephron ablation from surgical treatment (nephrectomy) renders the kidney susceptible to a multitude of problems over time in patients with WT. In this article, we review the existing literature pertaining to renal function in these patients. Incidence rates, causes, and methods to mitigate renal dysfunction are presented in 3 distinct clinical situations: sporadic unilateral WT, syndromic unilateral WT, and bilateral WT. We also offer a critical lens on the current role of nephron-sparing surgery as a means to preserve renal function in these patients. Finally, we discuss potential avenues for refining renal function preservation in patients with WT in the future. We conclude that: (1) renal function in pediatric cancer survivors must be carefully ascertained prospectively using methods that allow diagnosis of mild cases (rather than focus solely on extreme cases represented by the development of end-stage renal disease), (2) every effort should be made to recognize subtle features of predisposition syndromes to avoid syndromic cases from being misclassified and treated as sporadic, (3) molecular stratification for disease aggressiveness as well as multifocality and renal dysfunction will be very important to tailor treatment and balance survival with preservation of renal function, and (4) the role and potential benefits of nephron-sparing surgery deserves careful exploration under well-designed protocols.

(Epi)genotype-phenotype correlations in Beckwith-Wiedemann syndrome: a paradigm for genomic medicine

Beckwith-Wiedemann syndrome (BWS) is the commonest overgrowth cancer predisposition disorder and represents a model for human imprinting dysregulation and tumorigenesis. BWS features can variably combine and present a widely variable range of severity in the phenotypic expression. This wide spectrum is paralleled at molecular level by complex (epi)genetic defects on chromosome 11p15.5 leading to disrupted expression of imprinted genes controlling growth and cellular proliferation. In this review, we outline the spectrum of clinical manifestations of BWS analyzing their (epi)genotype-phenotype correlations. The differences observed in the phenotypic profiles of BWS molecular subtypes allow a composite view of this syndrome with implications on clinical care, diagnosis, follow-up, and management, and provide directions for future disease monitoring.

Wilms' tumour: Determinants of prognosis in an African setting

BACKGROUND

The few studies available in the literature on Wilms' tumour (WT) from sub-Saharan Africa have reported a dismal outcome for children with the tumour. This study evaluated the risk factors that have been correlated with outcome in the literature and compare these with outcome among our patients.

MATERIALS AND METHODS

Cases of histologically confirmed WT between 2009 and 2013 in a tertiary hospital in Northwestern Nigeria were evaluated for gender, age, laterality, symptoms, duration before presentation, stage at presentation, histologic subtype and p53 mutation. These were then correlated with outcome.

RESULTS

Totally, 30 cases of WT were diagnosed with mean age of 4.8 ± 1.9 years; and male:female ratio of 2:1. No statistically significant relationship with outcome was found for gender (P = 0.138) or histologic subtype (P = 0.671). The most significant variables which positively influenced the outcome were presentation at earlier stages (P = 0.007) and completion of therapy (P = 0.0007). p53 mutation was seen in 3 (16.7%) of 18 cases and was not associated with a poor outcome (P = 0.089). However, 2 of the 3 cases presented in Stage IV and none of them survived the 1 st year.

CONCLUSION

This study shows that even though p53 mutation was associated with a more aggressive phenotype, the most significant determinants of a good outcome among patients in a developing country like ours is non-blastemal dominant histologic subtype, early stage at presentation and completion of therapy.

An approach to renal masses in pediatrics

Renal masses in children may be discovered during routine clinical examination or incidentally during the course of diagnostic or therapeutic procedures for other causes. Renal cancers are rare in the pediatric population and include a spectrum of pathologies that may challenge the clinician in choosing the optimal treatment. Correct identification of the lesion may be difficult, and the appropriate surgical procedure is paramount for lesions suspected to be malignant. The purpose of this article is to provide a comprehensive overview regarding the spectrum of renal tumors in the pediatric population, both benign and malignant, and their surgical management.

The evolution of treatment for Wilms tumor

The prognosis for children with Wilms tumor (WT) has improved dramatically as the result of advances in surgical techniques, anesthesia, and supportive care. During the last three decades, the National Wilms Tumor Study Group (NWTSG), the International Society of Pediatric Oncology (SIOP), and the United Kingdom Children's Cancer Study Group (UKCCSG) conducted sequential studies of treatments for children with WT. The National Wilms Study Group demonstrated that radiation therapy is not necessary for those with Stage I and II, favorable histology Wilms tumor, and that the dose necessary for local control for those with local Stage III disease is 1050 to 1080 cGy. Administration of actinomycin D and doxorubicin using a single dose rather than divided dose schedule produced less myelosuppression and equivalent outcomes. Loss of heterozygosity for chromosomes 1p and 16q was associated with an inferior outcome. Areas for future investigation include the role of whole lung irradiation in the treatment of those with pulmonary metastases, the use of parenchymal sparing surgical techniques for removal of Wilms tumors, and identification of minimal necessary therapy.

Pathology, genetics and cytogenetics of Wilms' tumour

Wilms' tumour (WT) is an embryonal cancer of childhood and is thought to be derived from embryonic kidney precursor cells. The Knudson two hit model was initially thought to occur in WT, but findings emerging from genetic and cytogenetic studies in the past two decades have implicated several genetic events. Recent techniques in genetic analysis have improved our ability to characterise changes in genes involved in WT which include WT1, CTNNB1, IGF2 and WTX. These genetic events have not only provided insight into the pathobiology of this malignancy, but the recognition of these candidate genes may offer potential targets for novel therapies. In this review, we will provide an overview of the pathological, genetic and cytogenetic characteristics of WT.

Educational paper: screening in cancer predisposition syndromes: guidelines for the general pediatrician

Improvements in our understanding of the genetic basis of human disease and increased utilization of genetic testing have identified a variety of heritable disorders associated with the onset of benign or malignant neoplasms during childhood. In many cases, the optimal management of affected children is dependent upon the early detection and treatment of tumors. Surveillance strategies based on the natural history of these lesions are often complex, requiring clinical examinations and radiologic and laboratory studies that evolve over a patient's lifetime. A general pediatrician may be the first to suspect one of these disorders in a patient, or may be faced with questions regarding genetic testing, cancer risk, and cancer screening. The pediatrician may also coordinate and interpret the results of specific surveillance studies. In this review, we present the genetic etiology, presentation, natural history, and surveillance recommendations for four disparate hereditary tumor predisposing syndromes, including Beckwith-Wiedemann syndrome/idiopathic hemihyperplasia, von Hippel-Lindau disease, Li-Fraumeni syndrome, and rhabdoid tumor/schwannomatosis. These examples are meant to offer the clinician practical recommendations as well as a framework upon which to base the understanding and management of other conditions associated with an increased risk to develop tumors in childhood.

Current management of wilms' tumor

Wilms' tumor is the most common malignant renal tumor in children. Survival has improved dramatically over time as a result of prospective randomized clinical trials conducted by the pediatric cooperative cancer groups. Current research is directed toward identifying low-risk patients for whom a reduction in treatment intensity would decrease long-term morbidity. This article reviews the most recent advances in the biology and treatment of children with Wilms' tumor.

Current management of Wilms' tumor in children

PURPOSE

Wilms' tumor is the most common renal tumor in children. Outcomes have improved dramatically over the past few decades, but important treatment questions remain. These include the role of molecular biologic markers in stratifying patients for therapy or targeting tumors for treatment. We present a summary of these advances and outline the current treatment of Wilm's tumor.

MATERIALS AND METHODS

The medical literature and results of all cooperative group studies reporting treatment of children with Wilms' tumor were reviewed.

RESULTS

Overall survival exceeds 90% for most patients with nephroblastoma. However, outcomes for patients with rhabdoid tumors and diffuse anaplasia remain poor. The role of renal sparing surgery in patients with bilateral tumors is clear, but for children with unilateral tumors it continues to be defined.

CONCLUSIONS

Current protocols conducted by pediatric oncology groups are beginning to incorporate biologic features to stratify patients for therapy. Treatment strategies continue to focus on limiting late effects of treatment while maintaining an excellent survival. New therapies are needed to treat the high-risk patients who continue to have high relapse and mortality rates.

Renal tumours of childhood: an update

The role of the pathologist has been fundamental in the progress of the treatment of paediatric renal tumours. There are different philosophies in the treatment of these tumours, and there have been many recent advances in the areas of chemotherapy, identification of new entities, prognostic histological criteria following treatment and molecular prognostic and diagnostic features. This review discusses the different approaches of the different treatment protocols from Europe and North America, and reviews staging criteria, prognostic criteria and also the different tumour entities.

Wilms tumor: progress and considerations for the surgeon

Wilms tumor (WT) or nephroblastoma is the most common tumor of renal origin found in children. It accounts for 6% of all pediatric tumors and is the second most frequent intrabdominal solid organ tumor found in children. Initial survival rates in the early part of the last century was only 30%, but now long-term survival in both North America and European trials is approaching 85% with many low-stage tumors significantly higher. Treatment is now progressing towards "risk-based management"- based not only on stage and histology but also incorporating genetic markers [Dome JS, Grundy PE, Perlman EJ, Ehrlich PF, et al. Protocols for the renal tumors study. Childrens Oncology Group. [www.childrensoncologygroup.org. 2007.]. Within the multidisciplinary treatment team the surgeon plays a critical role in the diagnosis, staging and the surgeon's technical skills and judgment directs therapy and impacts outcome. The next generation of treatment for children with WT will focus on identifying subsets of patients who can be defined by some criterion as having a different outcome than their similar stage peers and who therefore require a variation in management. These include children with WT that have unsatisfactory long-term survival (less then 75%), patients of good survival but high potential for late effects and a final challenge are those children with both a poor survival and a high potential for late effects. This article presents a review of the most recent treatment considerations for WT with a focus on the surgeon's role to ensure a good outcome.

Congenital abnormalities and clinical features associated with Wilms’ tumour: A comprehensive study from a centre serving a large population

Altogether 156 children treated for Wilms' tumour (WT) between 1970 and 1998 were studied. Sixty-six children, selected only by their attendance at clinic, were carefully examined and the findings compared to those from a case note review of 90 children. Congenital abnormalities were present in 45% of the examined cohort, in 19% of the case notes review group and in 30% overall. Novel findings included the association of WT with Marshall Smith syndrome, developmental delay in 3 of 4 cases of WT (one bilateral) and 1 sibling from consanguineous Pakistani families and another sibling also had leukaemia. The possibility of rare DNA repair or cancer predisposing disorders among these 4 families requires further study. Careful examination and history taking of an unselected patient cohort revealed a higher than expected incidence of clinical abnormalities which may be overlooked if not specifically sought.

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.

Identification of limited regions of genetic aberrations in patients affected with Wilms' tumor using a tiling-path chromosome 22 array

Wilms' tumor (WT) is one of the most common solid tumors of childhood. The genetics of this disorder is complex and few studies have suggested allelic loss of chromosome 22 as a frequent aberration. To assess tumor- and possible germline-specific regions affected with gene copy number variations on this chromosome, we applied a high-resolution genomic clone-based chromosome 22 array to a series of 28 WT samples and the paired blood-derived DNA of the patients. The group of tumors was enriched for cases with metastases, relapse or fatal outcome, criteria that were expected to yield a higher number of alterations on chromosome 22. Overall, the array-based form of comparative genomic hybridization (array-CGH) analysis revealed genomic changes in 53% (15 out of 28) of cases. We identified hemizygous deletion of the whole arm of 22q in 3 tumors (11%). Furthermore, a complex amplifier genotype was detected in 8 samples, presenting regions of gain along the chromosome, which defined 7 distinct minimal overlapping segments. The distribution of aberrations in 4 additional cases displaying regional genomic imbalances delimited 2 tumor suppressor/oncogene candidate loci, 1 in the proximal and the other in the terminal part of 22q. Analysis of these regions revealed the presence of several candidate genes that may play a role in the development of WT. These findings demonstrate the power of array-CGH in the determination of DNA copy number alterations and further strength the notion that WT-associated genes exist on this chromosome.

Follow-up and risk of tumors in overgrowth syndromes

A striking feature of the overgrowth syndromes (OGS) is the risk of cancer. In some OGS (Beckwith-Wiedemann, Perlman, Simpson-Golabi-Behmel syndromes and hemihypertrophy) tumors appeared mostly in the abdomen (more than 94% of tumors), are usually diagnosed before 10 years, and most of them are embryonal. Conversely, in other OGS, such as Sotos syndrome, the most frequent type is lympho-hematological tumors, about two-thirds are extra-abdominal and some of these tumors may appear after the second decade of life. Based on a previous literature review, a specific schedule protocol for tumor screening was suggested for many OGS. In this article we briefly review some aspects of the current knowledge of OGS and tumors, emphasizing the follow-up of these disorders.

Risk of tumorigenesis in overgrowth syndromes: a comprehensive review

Overgrowth syndromes (OGS) comprise a heterogeneous group of disorders in which the main characteristic is that either weight, height, or head circumference is 2-3 standard deviations (SD) above the mean for sex and age. A striking feature of OGS is the risk of neoplasms. Here, the relative frequency of specific tumors in each OGS, topographic location, and age of appearance is determined by reviewing published cases. In some OGS (Perlman, Beckwith-Wiedemann, and Simpson-Golabi-Behmel syndromes and hemihyperplasia) more than 94% of tumors appeared in the abdomen usually before 10 years of age, mainly embryonal in type. In Perlman syndrome, only Wilms tumor has been recorded, whereas in Sotos syndrome, lympho-hematologic tumors are most frequent. Based on literature review, a specific schedule protocol for tumor screening is suggested for each OGS. A schedule with different intervals and specific tests is proposed for a more rational cost/benefit program for these disorders.