Screening of children with hemihypertrophy, aniridia, and Beckwith-Wiedemann syndrome in patients with Wilms tumor: a report from the National Wilms Tumor Study

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.

Characteristics of Nephroblastoma/Nephroblastomatosis in Children with a Clinically Reported Underlying Malformation or Cancer Predisposition Syndrome

Simple Summary

It is well known that different cancer predisposition syndromes are associated with characteristic WT-features. The following findings from our retrospective analysis of patients with nephroblastoma treated according to the SIOP/GPOH trials between 1989 and 2017 are relevant: (1) The outcome of patients with a cancer predisposition syndrome is not always favorable despite early diagnosis, small tumors and less metastatic disease. This finding is partly depending on complications related to the underlying syndrome. (2) Predisposition syndromes seem to be underdiagnosed as several clinical and pathological features of Wilms tumor being clearly linked to a cancer predisposition syndrome did not lead to genetic counseling before and after WT diagnosis. As a conclusion, in children with a nephroblastoma and specific clinical and pathological features that are in line with a nephroblastoma cancer predisposition syndrome such a syndrome should always be considered and ruled out if unknown at the time of tumor diagnosis.

Abstract

(1) Background: about 10% of Wilms Tumor (WT) patients have a malformation or cancer predisposition syndrome (CPS) with causative germline genetic or epigenetic variants. Knowledge on CPS is essential for genetic counselling. (2) Methods: this retrospective analysis focused on 2927 consecutive patients with WTs registered between 1989 and 2017 in the SIOP/GPOH studies. (3) Results: Genitourinary malformations (GU, N = 66, 2.3%), Beckwith-Wiedemann spectrum (BWS, N = 32, 1.1%), isolated hemihypertrophy (IHH, N = 29, 1.0%), Denys-Drash syndrome (DDS, N = 24, 0.8%) and WAGR syndrome (N = 20, 0.7%) were reported most frequently. Compared to others, these patients were younger at WT diagnosis (median age 24.5 months vs. 39.0 months), had smaller tumors (349.4 mL vs. 487.5 mL), less often metastasis (8.2% vs. 18%), but more often nephroblastomatosis (12.9% vs. 1.9%). WT with IHH was associated with blastemal WT and DDS with stromal subtype. Bilateral WTs were common in WAGR (30%), DDS (29%) and BWS (31%). Chemotherapy induced reduction in tumor volume was poor in DDS (0.4% increase) and favorable in BWS (86.9% reduction). The event-free survival (EFS) of patients with BWS was significantly (p = 0.002) worse than in others. (4) Conclusions: CPS should be considered in WTs with specific clinical features resulting in referral to a geneticist. Their outcome was not always favorable.

Advanced-stage Wilms tumor arising in a horseshoe kidney of a 9-year-old child: a case report

BACKGROUND

Horseshoe kidney (HK) is one of the most common renal fusion abnormalities, with an incidence of 1:400 in the normal population. However, Wilms tumor (WT) arising in an HK is a rare occurrence. We report the case of a 9-year-old boy who presented with an advanced WT in an HK and also highlight the management challenges in a resource-poor setting such as ours.

CASE PRESENTATION

The patient was a 9-year-old Nigerian boy presented to the Pediatrics Outpatient Clinic of the University of Maiduguri Teaching Hospital (UMTH) with a history of progressive abdominal swelling, weight loss, abdominal pain, and cough. Abdominal examination revealed an irregular, firm, and non-tender mass in the right lumbar region. A computed tomography (CT) scan of the abdomen showed a heterogeneously dense mass that was predominantly to the right side of the abdomen and crossed the midline to the left side, where it continued with the relatively normal renal tissue. Chest CT revealed pulmonary metastases. A diagnosis of WT in an HK was made. The patient had a 6-week course of neoadjuvant chemotherapy, and a right nephrectomy and left partial nephrectomy was performed. The final histologic diagnosis of WT was made. Radiotherapy was intended but was not available in our facility, and the parents could not afford referral to another center.

CONCLUSIONS

Children with a clinically suspected HK with WT should undergo a careful imaging evaluation such as CT before any surgical intervention. Neoadjuvant chemotherapy to reduce tumor bulk might be a good treatment method to reduce surgical morbidity and aid in complete excision and potential for preserving renal function.

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.

Genetic predisposition in pediatric oncology

Identifying patients with a genetic predisposition for developing malignant tumors has a significant impact on both the patient and family. Recognition of genetic predisposition, before diagnosing a malignant pathology, may lead to early diagnosis of a neoplasia. Recognition of a genetic predisposition syndrome after the diagnosis of neoplasia can result in a change of treatment plan, a specific follow-up of adverse treatment effects and, of course, a long-term follow-up focusing on the early detection of a second neoplasia.

Responsible for genetic syndromes that predispose individuals to malignant pathology are germline mutations. These mutations are present in all cells of conception, they can be inherited or can occur de novo.

Several mechanisms of inheritance are described: Mendelian autosomal dominant, Mendelian autosomal recessive, X-linked patterns, constitutional chromosomal abnormality and non-Mendelian inheritance.

In the following review we will present the most important genetic syndromes in pediatric oncology.

The effectiveness of Wilms tumor screening in Beckwith-Wiedemann spectrum

PURPOSE

It is well documented that patients with Beckwith-Wiedemann spectrum (BWS) have a significantly higher risk of developing Wilms tumor (WT) than the general population. There has been little research on the timing of WT diagnosis in BWS in regard to optimizing suggested screening protocols.

METHODS

A literature search was performed to identify all reports of patients with BWS and WT. These data were combined with unpublished data from patients in the authors' cohorts. Age at WT diagnosis was compared against data collected through the NIH Surveillance, Epidemiology, and End Results Program (SEER) registry.

RESULTS

Patients with BWS had a significantly higher incidence of WT diagnoses between age 12 and 84 months compared to patients in the SEER registry. Patients with BWS and WT diagnosed through screening had significantly lower stages at diagnosis compared to patients with BWS that were not screened.

CONCLUSIONS

Screening until age 7 years is effective in detecting close to 95% of all WT in patients with BWS.

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.

Surveillance Recommendations for Children with Overgrowth Syndromes and Predisposition to Wilms Tumors and Hepatoblastoma

A number of genetic syndromes have been linked to increased risk for Wilms tumor (WT), hepatoblastoma (HB), and other embryonal tumors. Here, we outline these rare syndromes with at least a 1% risk to develop these tumors and recommend uniform tumor screening recommendations for North America. Specifically, for syndromes with increased risk for WT, we recommend renal ultrasounds every 3 months from birth (or the time of diagnosis) through the seventh birthday. For HB, we recommend screening with full abdominal ultrasound and alpha-fetoprotein serum measurements every 3 months from birth (or the time of diagnosis) through the fourth birthday. We recommend that when possible, these patients be evaluated and monitored by cancer predisposition specialists. At this time, these recommendations are not based on the differential risk between different genetic or epigenetic causes for each syndrome, which some European centers have implemented. This differentiated approach largely represents distinct practice environments between the United States and Europe, and these guidelines are designed to be a broad framework within which physicians and families can work together to implement specific screening. Further study is expected to lead to modifications of these recommendations. Clin Cancer Res; 23(13); e115-e22. ©2017 AACRSee all articles in the online-only CCR Pediatric Oncology Series.

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.

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.

Beckwith-Wiedemann syndrome: growth pattern and tumor risk according to molecular mechanism, and guidelines for tumor surveillance

BACKGROUND

Beckwith-Wiedemann syndrome (BWS) is an overgrowth syndrome associated with an increased risk of pediatric tumors. The underlying molecular abnormalities may be genetic (CDKN1C mutations or 11p15 paternal uniparental isodisomy, pUPD) or epigenetic (imprinting center region 1, ICR1, gain of methylation, ICR1 GOM, or ICR2 loss of methylation, ICR2 LOM).

AIM

We aimed to describe a cohort of 407 BWS patients with molecular defects of the 11p15 domain followed prospectively after molecular diagnosis.

RESULTS

Birth weight and length were significantly higher in patients with ICR1 GOM than in the other groups. ICR2 LOM and CDKN1C mutations were associated with a higher prevalence of exomphalos. Mean adult height (regardless of molecular subtype, n = 35) was 1.8 ± 1.2 SDS, with 18 patients having a final height above +2 SDS. The prevalence of tumors was 8.6% in the whole population; 28.6 and 17.3% of the patients with ICR1 GOM (all Wilms tumors) and 11p15 pUPD, respectively, developed a tumor during infancy. Conversely, the prevalence of tumors in patients with ICR2 LOM and CDKN1C mutations were 3.1 and 8.8%, respectively, with no Wilms tumors.

CONCLUSION

Based on these results for a large cohort, we formulated guidelines for the follow-up of these patients according to the molecular subtype of BWS.

Innovations in the management of Wilms' tumor

Advances in the management of Wilms' tumor have been dramatic over the past half century, not in small part due to the institution of multimodal therapy and the formation of collaborative study groups. While different opinions exist in the management of Wilms' tumors depending on where one lives and practices, survival rates have surpassed 90% across the board in Western societies. With more children surviving into adulthood, the concerns about morbidity have reached the forefront and now represent as much a consideration as oncologic outcomes these days. Innovations in treatment are on the horizon in the form of potential tumor markers, molecular biological means of testing for chemotherapeutic responsiveness, and advances in the delivery of chemotherapy for recurrent or recalcitrant tumors. Other technological innovations are being applied to childhood renal tumors, such as minimally invasive and nephron-sparing approaches. Risk stratification also allows for children to forego potentially unnecessary treatments and their associated morbidities. Wilms' tumor stands as a great example of the gains that can be made through protocol-driven therapy with strenuous outcomes analyses. These gains continue to spark interest in minimization of morbidity, while avoiding any compromise in oncologic efficacy. While excitement and innovation are important in the advancement of treatment delivery, we must continue to temper this enthusiasm and carefully evaluate options in order to continue to provide the highest standard of care in the management of this now highly curable disease.

Malformations, genetic abnormalities, and Wilms tumor

BACKGROUND

Wilms Tumor (WT) can occur in association with tumor predisposition syndromes and/or with clinical malformations. These associations have not been fully characterized at a clinical and molecular genetic level. This study aims to describe clinical malformations, genetic abnormalities, and tumor predisposition syndromes in patients with WT and to propose guidelines regarding indications for clinical and molecular genetic explorations.

PROCEDURE

This retrospective study analyzed clinical abnormalities and predisposition syndromes among 295 patients treated for WT between 1986 and 2009 in a single pediatric oncological center.

RESULTS

Clinically identified malformations and predisposition syndromes were observed in 52/295 patients (17.6%). Genetically proven tumor predisposition syndromes (n = 14) frequently observed were syndromes associated with alterations of the chromosome WT1 region such as WAGR (n = 6) and Denys-Drash syndromes (n = 3), syndromes associated with alterations of the WT2 region (Beckwith-Wiedeman syndrome, n = 3), and Fanconi anemia (n = 2). Hemihypertrophy and genito-urinary malformations (n = 12 and n = 16, respectively) were the most frequently identified malformations. Other different syndromes or malformations (n = 10) were less frequent. Median age of WT diagnosis was significantly earlier for children with malformations than those without (27 months vs. 37 months, P = 0.0009). There was no significant difference in terms of 5-year EFS and OS between WT patients without or with malformations.

CONCLUSIONS

The frequency of malformations observed in patients with WT underline the need of genetic counseling and molecular genetic explorations for a better follow-up of these patients, with a frequently good outcome. A decisional tree, based on clinical observations of patients with WT, is proposed to guide clinicians for further molecular genetic explorations.

Wilms tumor and a duplex collecting system: a case report and review of literature

Wilms tumor (WT) is described as a component of many different clinical conditions and genetic syndromes. However, the simultaneous occurrence of WT and a duplex collecting system is extremely rare. We report a case of a 4-year-old boy diagnosed with WT and a left duplex collecting system. The patient underwent a left radical nephrectomy. The histologic examination diagnosed it to be a case of WT with favorable histology. The patient received the chemotherapy regimen for stage 1 WT and was in complete remission during the follow-up period of 2 years. Further investigations are required for assessing the need for screening of WT in children with genitourinary malformations.

Pediatric urologic oncology

This article reviews common pediatric urologic cancers involving the genitourinary system. Rhabdomyosarcoma may occur in the bladder, prostate, paratesticular regions, vagina, or uterus. Some of these locations, such as the paratesticular region, have a more favorable outcome. Benign neoplasms account for the majority of pediatric testicular tumors and most are managed with testis-sparing surgery. Most genitourinary malignancies are expected to have a good outcome. One focus of treatment is organ preservation but not at the expense of a good oncologic outcome. Late sequelae of anticancer therapy are a concern and every attempt is made to decrease the intensity of tumor treatment.

Incidence of abdominal tumors in syndromic and idiopathic hemihypertrophy/isolated hemihyperplasia

BACKGROUND

There is a reported increased risk of intra-abdominal tumors in children with both syndromic (SH) and isolated idiopathic hemihyperplasia (IH). Recommendations for tumor surveillance have been made, although there is no consensus for frequency and duration of screening. Our objective was to review the incidence of abdominal neoplasms in our pediatric population with SH and IH.

METHODS

We reviewed the diagnostic criteria, imaging findings, and any associated syndrome in all patients diagnosed with hemihypertrophy over a 10-year period.

RESULTS

One of 10 patients with SH, a child with Beckwith-Wiedemann syndrome, developed a hepatoblastoma resulting in a 10% tumor incidence in patients with SH. Three of the 250 (1.2%) children with IH developed an abdominal neoplasm. One was diagnosed with adrenal carcinoma and the other 2 with Wilms tumor.

CONCLUSIONS

We found an increased incidence of abdominal tumors in both SH and IH, however, our incidence of tumors with IH is lower than earlier reported studies. On the basis of this lower 1.2% incidence, the current literature on IH and available molecular genetic testing, it is reasonable to recommend referral of these patients to a clinical geneticist to identify subgroups with a higher risk for tumor development that are more likely to benefit from routine imaging surveillance.

LEVEL OF EVIDENCE

II-Retrospective study.

Adrenal cortical tumors in children: factors associated with poor outcome

PURPOSE

The purpose of this study was to evaluate recurrence and survival outcomes in pediatric adrenal cortical neoplasms.

METHODS

A 90-year retrospective review of children with adrenal cortical neoplasms was performed using multivariate Cox regression analysis to identify factors associated with recurrence and tumor-related mortality.

RESULTS

The evaluable cohort included 29 patients. Twenty-seven underwent resection. Twenty-two (81%) had localized disease, and 5 (19%) had locally advanced disease (all received chemotherapy and 2 of 5 were cured). Two patients presenting with metastatic disease died despite treatment. There were 4 recurrences; all patients died. Tumor-related mortality was 24% (7/29). Kaplan-Meier freedom from recurrence was 85% at 1 year (95% confidence interval, 75%-95%). Multivariate Cox regression revealed that older age (P = .01), higher mitotic rate (P = .005), and necrosis (P < .001) were independent predictors of tumor-related death. Higher mitotic rate (P = .007) and larger tumor size (P = .03) were significant predictors of tumor recurrence.

CONCLUSION

Risk factors for poor outcomes in patients with adrenocortical tumors include older age, higher mitotic rate, higher percent necrosis, and larger tumor size. Therefore, the presence of these factors may warrant consideration of adjuvant chemotherapy, even in the absence of advanced disease.

Molecular Pathology of the Genitourinary Tract: Molecular Pathology of Kidney and Testes

With the advent of newer molecular technologies, our knowledge of cellular mechanisms with tumors of the kidney and testis has grown exponentially. Molecular technologies have led to better understanding of interplay between the von Hippel-Lindau gene and angiogenic cytokines in renal cancer and isochromosome 12p in testicular neoplasms. The result has been development of antiangiogenic-targeted therapy within recent years that has become the mainstay treatment for metastatic renal cell cancer. In the near future, classification and diagnosis of renal and testicular tumors through morphologic analysis will be supplemented by molecular information correlating to prognosis and targeted therapy. This article outlines tumor molecular pathology of the kidney and testis encompassing current genomic, epigenomic, and proteonomic findings.

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.

Eosinophilic chromophobe renal cell carcinoma in a child with hypospadias

Chromophobe renal cell carcinoma (CRCC) is a distinct variant of renal carcinoma generally affecting adults. We report a case of an unusual CRCC, arising in a male child affected by hypospadias. This case demonstrates that CRCC can occur in the pediatric patients and can be associated with genital tract anomalies such as Wilms tumor.

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.

Should children at risk for familial adenomatous polyposis be screened for hepatoblastoma and children with apparently sporadic hepatoblastoma be screened for APC germline mutations?

BACKGROUND

Hepatoblastoma (HB) is the most frequent liver tumor in childhood, occurring in the first few years of life. Surgery combined with chemotherapy has resulted in dramatic improvements in prognosis. However, even today, about one quarter of affected children do not survive the disease. Compared to the general population, the risk of HB is 750-7,500 times higher in children predisposed to familial adenomatous polyposis (FAP), an autosomal-dominant cancer predispostion syndrome caused by germline mutations in the tumor suppressor gene APC. Only limited data exist about the frequency of APC germline mutations in cases of apparently sporadic HB without a family history of FAP.

PROCEDURE

In our sample of 1,166 German FAP families, all known cases of HB were registered. In addition, 50 patients with apparently sporadic HB were examined for APC germline mutations.

RESULTS

In the FAP families, seven unrelated cases of HB are documented; three had been detected at an advanced stage. In patients with apparently sporadic HB, germline mutations in the APC gene were identified in 10%.

CONCLUSIONS

These data raise the issue of the appropriate screening for HB in children of FAP patients. To date, the efficiency of surveillance for HB is unclear. In Beckwith-Wiedemann syndrome (BWS), recent studies suggest an earlier detection of both Wilms tumor and HB by frequent screening. We discuss the rationale and implications of a screening program; besides the examination procedure itself, screening for HB in children of FAP patients would have important consequences for the policy of predictive testing in FAP. In a substantial fraction of sporadic HB, the disease is obviously the first manifestation of a de novo FAP. These patients should be identified by routine APC mutation screening and undergo colorectal surveillance thereafter.

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.

Tumour surveillance in Beckwith-Wiedemann syndrome and hemihyperplasia: a critical review of the evidence and suggested guidelines for local practice

There is strong evidence for an association between overgrowth disorders such as Beckwith-Wiedemann syndrome and the development of neoplasia. An increased cancer risk has also been observed in individuals with isolated hemihyperplasia. We critically review the evidence for tumour surveillance in Beckwith-Wiedemann syndrome and isolated hemihyperplasia and suggest local practice guidelines.

Classification of malignant pediatric renal tumors by gene expression

BACKGROUND

The most common malignant renal tumors of childhood are Wilms tumor (WT), clear cell sarcoma of the kidney (CCSK), cellular mesoblastic nephroma (CMN), and rhabdoid tumor of the kidney (RTK). Because these tumors present significant diagnostic difficulties, the goal was to define diagnostically useful signatures based on gene expression.

PROCEDURES

Gene expression analysis using oligonucleotide arrays was performed on a training set of 47 tumors (10 CCSKs, 9 CMNs, 8 RTKs, and 20 WTs). Classifiers were developed for each tumor type using variations of compound covariate class predictor. The classifiers were applied to an independent test set of 72 tumors (3 CMN, 7 CCSK, 4 RTK, and 58 WT). Central review diagnosis was utilized as the gold standard. Correlation with the institutional diagnosis and qualitative estimation of confidence levels at the time of central review were noted.

RESULTS

Within the training set, classifiers resulted in no errors when >10 genes were utilized. Top genes in each classifier were verified using quantitative reverse transcription-polymerase chain reaction (RT-PCR). Applying the classifiers to the test set, 71 of 72 tumors were correctly classified with a confidence level of >99%. The exception was incorrectly classified by the gold standard. In comparison, by histopathology 31% of the non-WT were not accurately classified by the local institution, and 29% were classified with <95% confidence on central review.

CONCLUSIONS

Classifiers based on gene expression provide diagnostic confidence and accuracy greater than that of pathologic analysis alone. Tumors that show ambiguous gene expression profiles are those that are also pathologically and molecularly ambiguous and merit further analysis.

Multicystic dysplastic kidney with ipsilateral abnormalities of genitourinary tract: experience in children

OBJECTIVES

To investigate the incidence, nature, and management of associated ipsilateral genitourinary malformations in children with multicystic dysplastic kidney (MCDK).

METHODS

In this retrospective study, we analyzed the medical records and imaging studies of 93 patients with MCDK. Patients underwent ultrasonography, voiding cystourethrography, intravenous urography, and radionuclide renal imaging studies during their first month of age.

RESULTS

A diagnosis of MCDK associated with malformation of the ipsilateral internal genitalia was confirmed in 11 patients after birth investigations of prenatal MCDK. Three were diagnosed at 1, 12, and 14 years of age because of epididymitis, pelvic pain associated with amenorrhea, and accidentally during lumbar pain assessment, respectively. The male/female sex ratio was 10:4. The left side was involved in 9 patients. We had 3 cases of Gartner duct persistence, 6 of cystic retrovesical and laterovesical masses with vanishing MCDK, 4 of cystic retrovesical or laterovesical masses with compressive MCDK, and 1 of a blind-ending hemivagina. Nine patients were periodically observed, and four underwent nephroureterectomy. All patients underwent 6-month follow-up examinations with ultrasonography (mean follow-up 6.54 years, range 36 months to 14 years).

CONCLUSIONS

Of the 93 patients with MCDK, 14 (15%) had malformations of the ipsilateral internal genitalia. Persistence of seminal cysts in boys and Gartner ducts were encountered even if the MCDK had involuted. These results suggest that follow-up of patients with MCDK should be performed until the end of puberty to detect genitourinary malformations.

Mechanisms predisposing to childhood overgrowth and cancer

Several overgrowth conditions are believed to be associated with elevated risks of cancer, particularly in childhood. Beckwith-Wiedemann syndrome and Sotos syndrome are the most common overgrowth conditions, and both carry increased risks of certain tumors. In recent years, the identification of both the gene causing Sotos syndrome and the epigenetic subgroups underlying Beckwith-Wiedemann syndrome have enabled clarification of the cancer types and risks associated with these conditions. This has revealed striking differences in the cancer phenotypes associated with different molecular abnormalities. Elucidation of the mechanisms underlying cancer in overgrowth syndromes might yield important insights into the molecular basis of childhood tumors.

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.

High incidence of malformation syndromes in a series of 1,073 children with cancer

Constitutional molecular defects are known to play a role in oncogenesis, as shown by the increased incidence of embryonic cancers in children with Beckwith-Wiedemann syndrome (BWS) or of leukemia in children with Down syndrome. To establish the incidence and spectrum of malformation syndromes associated with childhood cancer we performed a clinical morphological examination on a series of 1,073 children with cancer. We diagnosed a syndrome in 42 patients (3.9%) and suspected the presence of a syndrome in another 35 patients (3.3%), for a total of 7.2%. This incidence of patients with a proven or suspected syndrome is high, and points to a possible association. We describe new syndrome-tumor associations in several entities: cleidocranial dysostosis (Wilms tumor), Bardet-Biedl syndrome (BBS) (acute lymphoblastic leukemia), Kabuki syndrome (neuroblastoma), LEOPARD syndrome (neuroblastoma), Poland anomaly (osteosarcoma; Hodgkin disease), and blepharophimosis epicanthus inversus syndrome (Burkitt lymphoma). Twenty of the 42 syndrome diagnoses were not recognized in the patients prior to this study, indicating that these diagnoses are commonly missed. We propose that all children with a malignancy should be examined by a clinical geneticist or a pediatrician skilled in clinical morphology to determine if the patients have a malformation syndrome.

Current challenges in Wilms' tumor management

Wilms' tumor is a renal cancer that predominantly affects children during the first 2 years of life. The continuing success of clinical trials in Wilms' tumor patients over the past 30 years has led to an overall survival of 85%, and treatment-related morbidity has been reduced. Less-aggressive chemotherapeutic regimes are available for patients with validated good prognostic factors, such as low stage and favorable histology. It is becoming increasingly apparent that treatment can be optimized through stratification of patients according to tumor stage and histology. Established treatments for Wilms' tumor include perioperative vincristine and actinomycin, with or without doxorubicin or radiotherapy. Relapsed patients have the option of salvage chemotherapy with ifosfamide, carboplatin and etoposide, as well as high-dose chemotherapy regimes and autologous hemopoietic stem-cell rescue. Further research is required to refine these regimes and identify further the role of additional prognostic factors in this childhood disease. In this article we discuss the most-debated issues and advances that have been made in the management of Wilms' tumor.

Hemihypertrophy, renal dysplasia and benign nephromegaly

Hemihypertrophy is associated with malignant visceral abdominal neoplasms in childhood. Benign nephromegaly and nephroblastomas are both known to occur with hemihypertrophy; however, association with renal dysplasia has not previously reported. We describe an infant presenting with recurrent haematuria who had segmental hemihypertrophy, ipsilateral renal dysplasia and contralateral benign nephromegaly. Although debated, renal dysplasia may predispose to and predate malignant change. Rational management and optimal surveillance of renal dysplasia and benign nephromegaly in hemihypertrophy is discussed.

[Kidney tumors in childhood]

Types of renal tumors arising in children are different from those occurring in adults. Nephroblastoma is the most common (85%) with a clinical outcome which has dramatically improved in the last 30 years. Current classifications are aimed at better adaptation of treatment to each individual case, reducing iatrogenic complications without impairing total cure. Amongst entities which have been recently described or are better known we can find juvenile carcinoma associated with Xp11.2 translocation, renal medullary carcinoma, metanephric tumors, etc. Role of molecular cytogenetics is increasing for classification (and treatment) and this should always be kept in mind when dealing a fresh specimen of childhood renal tumor.

Three patients with hallucal polydactyly and WAGR syndrome, including discordant expression of Wilms tumor in MZ twins

The WAGR contiguous gene deletion syndrome is a combination of Wilms tumor, Aniridia, Genito-urinary abnormalities, and growth and mental retardation which is invariably associated with an 11p13 deletion. We report two monozygotic twins and a third, unrelated patient with WAGR syndrome and additional clinical features not usually associated with WAGR. Both twins had developmental delay, growth deficiency, severe ocular involvement (nystagmus, aniridia, cataracts), atrial septal defect and two uncommon findings: agenesis of the corpus callosum and duplication of the halluces. One twin developed Wilms tumors aged 19 months while her sister remained tumor free by the age of 6.5 years. The singleton patient showed typical WAGR syndrome and preaxial hallucal polydactyly. Molecular cytogenetic studies refined the identification of the extent of the deleted segments, which were not identical in the two families. The two deletions included the PAX6 and WT1 genes as previously reported in typical WAGR patients. The unusual anomalies described in this report, may represent the expression of low penetrant traits associated with haploinsufficency of one or more of the genes present in the deletion (PAX6 is expressed in CNS) or may indicate epistatic influences of modifier genes on the expression of gene(s) present in the WAGR region.

Tumor risk in Beckwith-Wiedemann syndrome: A review and meta-analysis

Beckwith-Wiedemann syndrome (BWS) is an overgrowth syndrome associated with macroglossia, abdominal wall defects, ear anomalies, and an increased risk for embryonic tumors. Reported tumor risk estimates vary between 4% and 21%. It has been hypothesized that tumor predisposition in BWS is related to the imprinting status of the H19 and LIT1 genes on chromosome 11p15. A loss of imprinting (LOI) of H19 implies a higher tumor risk. However, a systematic analysis of available data is lacking. Therefore, we performed a review and meta-analysis of reported associations between the imprinting status of the LIT1 and H19 genes and the risk for tumor development in BWS. Five publications suitable for meta-analysis were identified by electronic database searches. Sufficient data were available for 402 out of 520 patients. Patients were divided into four groups based on the imprinting status of H19 and LIT1: group I with LOI of LIT1 (45%); group II with LOI of H19 (9%); group III with LOI of LIT1 and LOI of H19 (21%); and group IV with normal imprinting patterns (26%). Differences in tumor risk between groups were studied with random effects meta-analysis. Tumors occurred in 55 patients. The odds of tumor development was significantly lower in group I when compared to group II (OR=0.06; 95% CI: 0.02-0.21) and group III (OR=0.12; 95% CI: 0.04-0.37). Tumor risk did not differ significantly between groups II and III (OR=1.40; 95% CI: 0.56-3.50). Compared to group IV, tumor risk was significantly lower in group I (OR=0.33; 95% CI: 0.12-0.87) and higher in groups II (OR=4.0; 95% CI: 1.5-10.4) and III (OR=2.6; 95% CI: 1.2-5.7). Tumor incidence rate for group IV was 10.6% (95% CI: 3.6-17.7). Calculated absolute risks were 3% for group I, 43% for group II, and 28% for group III, respectively. No Wilms tumor was seen in group I. In total, other tumors were seen with comparable frequencies in groups I-III. The results show a strong association between a LOI of H19 and especially Wilms tumor development in BWS.

Characteristics and outcomes of children with the Wilms tumor-Aniridia syndrome: a report from the National Wilms Tumor Study Group

PURPOSE

Children with the rare Wilms tumor (WT)-aniridia (WAGR) syndrome have not had systematic evaluation of their clinical and pathologic features. We compared demographics, disease characteristics, and treatment outcomes in a large cohort of WT patients who did or did not have the WAGR syndrome.

PATIENTS AND METHODS

Clinical and pathology records were reviewed for 8,533 patients enrolled between 1969 and 2002 by the National Wilms Tumor Study Group.

RESULTS

Sixty-four patients (0.75%) had the WAGR syndrome. For WAGR and non-WAGR patients, respectively, the average birth weights (2.94 and 3.45 kg), median ages at diagnosis (22 and 39 months), and the percentages with bilateral disease (17% and 6%), metastatic disease (2% and 13%), favorable histology (FH) tumors (100% and 92%), and intralobar nephrogenic rests (ILNR; 77% and 22%) all differed. Survival estimates for WAGR and non-WAGR patients were 95% +/- 3% and 92% +/- 0.3% at 4 years but 48% +/- 17% and 86% +/- 1.0%, respectively, at 27 years from diagnosis. Five late deaths in WAGR patients were from end-stage renal disease (ESRD).

CONCLUSION

The excess of bilateral disease, ILNR-associated FH tumors of mixed cell type, and early ages at diagnosis in WAGR patients all fit the known phenotypic spectrum of constitutional deletion of chromosome 11p13. Despite a favorable response of their WT to treatment, WAGR patients have a high risk of ESRD as they approach adulthood. The renal pathology associated with this apparent late manifestation of WT1 deletion, and the explanation for the abnormally low birth weights in patients with del 11p13, have yet to be determined.

Wilms' tumor and horseshoe kidneys: a case report and review of the literature

The presence of Wilms' tumor with a horseshoe kidney is an unusual combined clinical presentation. It has been reported that the incidence of Wilms' tumor in patients with horseshoe kidneys is higher than that seen in the general population. The current report describes a 5-year-old boy who presented with a stage III Wilms' tumor in a horseshoe kidney. The patient was treated with neoadjuvant chemotherapy followed by surgical resection, adjuvant chemotherapy, and radiation. The patient is disease free 40 months after diagnosis. A review of all reported cases of Wilms' tumor with horseshoe kidneys in the English-language literature before July 2002 is presented.

Controversies and advances in the management of Wilms' tumour

Wilms tumour is one of the success stories of paediatric oncology with long term survival approaching 90% in localised disease and over 70% for metastatic disease. Although appearing relatively simple compared to other cancer treatment regimens, successful treatment of Wilms tumour requires meticulous attention to correct staging of the tumour and good communication between the paediatric surgeon, pathologist and oncologist. The controversy of whether pre-operative chemotherapy results in a reduced overall burden of treatment compared to immediate nephrectomy has been addressed by the recently closed UKW3 randomised trial. Challenges remain in identification of histological and molecular risk factors for stratification of treatment intensity to allow safe reduction in therapy and avoidance of late sequelae for the majority while leading to increased biological insights and ultimately novel therapies for the minority of high risk tumours. Genetic predisposition to Wilms tumour is conferred by several genes, some of which cause malformation rather than cancer and may be of low penetrance. The proportion of children with heritable disease is uncertain and there remains a need to collect data on the need for screening in this susceptible population.

The occurrence of Wilms tumor in horseshoe kidneys: a report from the National Wilms Tumor Study Group (NWTSG)

BACKGROUND/PURPOSE

An increased incidence of Wilms tumor has been noted in patients with a horseshoe kidney. These represent a difficult diagnostic and therapeutic challenge. The charts of all National Wilms Tumor Study Group (NWTSG) patients with Wilms tumor occurring in a horseshoe kidney were reviewed.

METHODS

From 1969 to 1998, 8,617 patients were enrolled in the NWTSG. Forty-one patients were found to have a Wilms tumor arising in a horseshoe kidney for an incidence of 0.48%. Their records were reviewed retrospectively.

RESULTS

Horseshoe kidney was not recognized preoperatively in 13 patients, 10 of whom were evaluated with computed tomography (CT). Four of the 10 also had renal ultrasonography and one an intravenous pyelogram (IVP). Two of the 13 were evaluated with an IVP only, and the last had no preoperative imaging studies performed. Stage at presentation was stage I, 10 pts; stage II, 10; stage III, 12; stage IV, 6; stage V, 3. Primary surgical resection was performed in 26 patients, including 23 nephrectomies and 3 partial nephrectomies. Fifteen children were treated with preoperative chemotherapy after initial biopsy of the tumor. The mean total remaining renal parenchyma after all operations (excluding treatment of relapses) was approximately 75%. Surgical complications occurred in 14.6% of patients, including 2 urine leaks, 2 ureteral obstructions, and 1 ureteral injury. Two patients had transient renal failure.

CONCLUSIONS

The diagnosis of horseshoe kidney often was missed on preoperative imaging. Accurate preoperative diagnosis is important in planning the operative approach and may help to decrease complications related to transection of the urinary collecting system. Although 37% of patients with Wilms tumor arising in a horseshoe kidney were judged inoperable at initial exploration, all were amenable to resection after chemotherapy.

Screening for Wilms tumor and hepatoblastoma in children with Beckwith-Wiedemann syndromes: a cost-effective model

BACKGROUND

We undertook a cost-benefit analysis of screening for Wilms tumor and hepatoblastoma in children with Beckwith-Wiedemann syndrome (BWS), a known cancer predisposition syndrome. The purpose of this analysis was twofold: first, to assess whether screening in children with BWS has the potential to be cost-effective; second, if screening appears to be cost-effective, to determine which parameters would be most important to assess if a screening trial were initiated.

PROCEDURES

We used data from the BWS registry at the National Cancer Institute, the National Wilms Tumor Study (NWTS), and large published series to model events for two hypothetical cohorts of 1,000 infants born with BWS. One hypothetical cohort was screened for cancer until a predetermined age, representing the base case. The other cohort was unscreened. For our base case, we assumed: (a) sonography examinations three times yearly (triannually) from birth until 7 years of age; (b) screening would result in one stage shift downward at diagnosis for Wilms tumor and hepatoblastoma; (c) 100% sensitivity and 95% specificity for detecting clinical stage I Wilms tumor and hepatoblastoma; (d) a 3% discount rate; (e) a false positive result cost of $402. We estimated mortality rates based on published Wilms tumor and hepatoblastoma stage specific survival.

RESULTS

Using the base case, screening a child with BWS from birth until 4 years of age results in a cost per life year saved of $9,642 while continuing until 7 years of age results in a cost per life-year saved of $14,740. When variables such as cost of screening examination, discount rate, and effectiveness of screening were varied based on high and low estimates, the incremental cost per life-year saved for screening up until age four remained comparable to acceptable population based cancer screening ranges (< $50,000 per life year saved).

CONCLUSIONS

Under our model's assumptions, abdominal sonography examinations in children with BWS represent a reasonable strategy for a cancer screening program. A cancer screening trial is warranted to determine if, when, and how often children with BWS should be screened and to determine cost-effectiveness in clinical practice.

Sudden death in an 8-week-old infant with Beckwith-Wiedemann syndrome

The authors report a case of a 2-month-old girl diagnosed with Beckwith-Wiedemann syndrome (BWS) who was born prematurely and died suddenly in the hospital just before being discharged. BWS is a malformation syndrome associated with an increased risk of childhood tumors. The major features of BWS are macroglossia, abdominal wall defects, and visceromegaly, frequently leading to premature birth. Due to complex inheritance patterns, a predominance of nonfamilial cases, and the variability in expression of the features (termed incomplete penetrance), the risk of delayed diagnosis is evident. Secondary to hyperplastic pancreatic islands, hypoglycemia occurs frequently, and if not anticipated, adequate measures for prevention of hypoglycemic episodes may be delayed, resulting in possible intellectual deficits. The infant presented here died of natural causes: immaturity of the lungs resulting in marginal respiratory function and compounded by increased risk for asphyxia secondary to the enlarged tongue. The clinical history and findings in this infant are discussed in respect to the genetic syndrome with their relevance to medicolegal examination and the causes and manner of death.

Wilms' tumor. Overview of National Wilms' Tumor Study Group results

Since its inception in 1969, the NWTSG has performed successful studies that are now the model for the management of pediatric malignancies. Future studies may use genetic markers to stratify high-risk patients beyond the traditional staging system. Therapy will continue to be evaluated to determine the minimal therapy necessary to achieve the best outcome for children with Wilms' tumor.

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

PURPOSE

Children with Beckwith-Wiedemann syndrome (BWS) are at increased risk for developing Wilms' tumor (WT). We reviewed the National Wilms Tumor Study Group (NWTSG) records to assess clinical characteristics and outcome of patients with WT and BWS.

METHODS

In the NWTSG, treating clinicians were asked to report, for each enrolled patient, whether the patient had BWS. Between 1980 and 1995, 4,669 patients were treated on two consecutive NWTSG protocols (NWTS 3 and NWTS 4). We retrospectively reviewed the clinical characteristics and treatment outcomes of BWS patients compared with patients with WT without BWS.

RESULTS

Fifty-three children enrolled onto NWTS 3 and 4 were reported to have BWS. BWS patients were more likely to present with lower-stage tumors (P =.0001), with more than half (27 of 53) presenting with stage I disease. The overall treatment outcomes for the BWS patients were nearly identical to those without BWS, with overall survival at 4 years from diagnosis at 89% and 90%, respectively. Overall, 21% of the patients with BWS had bilateral disease, either at diagnosis (nine of 53) or as metachronous contralateral recurrence (two of 53). BWS patients enrolled onto NWTS 4 had smaller tumors than those enrolled onto NWTS 3 (P =.02), a trend not seen in the non-BWS patients.

CONCLUSION

Like children without BWS, children with BWS and WT have an excellent prognosis with modern treatment regimens. There is a high risk of bilateral disease, and increasingly smaller tumors are being detected. This suggests that a national trial assessing the role of ultrasound screening followed by nephron-sparing surgery for some patients may be appropriate.

Wilms tumor in a child with trisomy 13

A 4-year-old black boy with trisomy 13, a history of frequent urinary tract infections, and a horseshoe kidney with painless gross hematuria was examined. An abdominal mass was detected and surgically resected. Examination of the surgical specimen revealed a Wilms tumor. Given the concurrence of trisomy 13 and Wilms tumor and the presence of another such case in the literature, there may be just cause to suspect a locus on chromosome 13 that affects the probability of developing Wilms tumor. Given the increasingly longer survival of patients with trisomy 13, clinicians may need to be aware of the possibility of renal malignant disease in this population of patients.

Risk-based management: current concepts of treating malignant solid tumors of childhood

BACKGROUND

Improved survival with pediatric malignancies has been positively influenced by multidisciplinary cooperative studies using surgery, chemotherapy, and radiation therapy, but one-third of all children with cancer succumb to their condition. The identification of biologic and genetic characteristics as risk factors for the various tumors has led to changes in treatment using risk-based management as the template for care.

STUDY DESIGN

The purpose of this report is fourfold: (1) to review survival data concerning three solid malignant tumors of childhood (Wilms' tumor, rhabdomyosarcoma, and neuroblastoma), (2) to describe important prognostic genetic and biologic risk factors for each tumor, (3) to update changes in staging criteria, and (4) to familiarize the reader with the concept of risk-based management, which individualizes treatment in an attempt to maximize survival and minimize longterm morbidity.

RESULTS

The overall survival rates for Wilms' tumor, rhabdomyosarcoma, and neuroblastoma are currently 90%, 70%, and 40%, respectively. Most patients with Wilms' tumor have favorable histology and survive after nephrectomy and chemotherapy, but 10% have poor prognostic variables, including unfavorable (anaplastic) histology, chromosomal loss on 1p and 16q, and diploidy. Instances of lung or liver metastases, major tumor spillage during resection, remote lymph node involvement, and bilateral tumors have worse outcomes. Rhabdomyosarcoma is associated with chromosomal translocation of t(2:13) in alveolar types, the p53 tumor suppressor gene, and 11p15. Survival is dependent on the tumor site and pretreatment clinical group. Orbit, paratesticular, vulvar, and vaginal tumors have a good prognosis, but other genitourinary tumors, extremity and trunk lesions, and parameningeal head and neck tumors have a worse prognosis. Survival rates by clinical group are stage I, 93%; II, 81%; III, 73%; and IV, 30%. Resectability, lymph node involvement, DNA ploidy, and pretreatment TNM staging affect outcomes. Neuroblastoma is an embryonal tumor with bizarre behavior and can regress, mature, or rapidly progress. Most patients have advanced disease at diagnosis. Neuroblastoma is associated with loss of heterozygosity on chromosome 1p36 and occasionally deletions on 14q and 17q. Survival is affected by age and stage (at less than 1 year, stages I [95% to 100%], II [85% to 90%], and IV-S [more than 80%] do better) and other risk factors. Patients with advanced disease (older than 1 year, stage III [70%], and stage IV [12%]) often have amplification of the N-myc oncogene, diploid tumors, 1p36 deletion, and unfavorable histology and fare worse.

CONCLUSIONS

On the basis of these data, children with solid tumors are currently categorized into low-, intermediate-, and high-risk groups. Newer protocols individualize treatment using risk factors as predictors of outcomes. Risk-based management allows the clinician to weigh the risks and benefits of treatment for each patient to maximize survival, minimize longterm morbidity, and improve the quality of life.

Pediatric renal tumors

A broad spectrum of renal tumors occurs in infants and children ranging from the benign cystic nephroma to the extremely aggressive malignant rhabdoid tumor of the kidney. A thorough understanding of these tumors is crucial to the optimal diagnosis and management of children with renal masses. The common renal tumors in infants and children are discussed and an orderly method for their evaluation is presented. Recent developments in the molecular biology of Wilms' tumor are outlined to provide insight into the origin of this tumor.

Screening for Wilms tumor in children with Beckwith-Wiedemann syndrome or idiopathic hemihypertrophy

BACKGROUND

Children with Beckwith-Wiedemann syndrome and idiopathic hemihypertrophy (BWS/HH) are at increased risk for developing Wilms tumor and screening with abdominal sonography is frequently recommended. However, there is a paucity of published data supporting this strategy. The purpose of this study was to determine whether sonographic screening at intervals of 4 months or less reduced the proportion of late-stage Wilms Tumor (WT) in children with BWS/HH.

PROCEDURE

A case series analysis was employed to compare the proportion of late-stage (stage III or IV) Wilms tumor in patients with BWS/HH who were screened with sonography (n = 15) to the proportion of late-stage Wilms tumor in unscreened patients with BWS/HH (n = 59). Patients were identified from the BWS Registry and from previously published studies. Screened patients had sonograms at intervals of 4 months or less.

RESULTS

None of the 12 screened children with Wilms tumor had late-stage disease, whereas 25 of 59 (42%) of unscreened children had late-stage Wilms tumor, a difference that was statistically significant (P < 0.003). Three children had false positive screening studies. They were operated on for suspected Wilms tumor but the lesions proved to be complicated renal cysts (n = 2) or nephroblastomatosis (n = 1).

CONCLUSIONS

This study suggests that children with BWS/HH may benefit from screening sonograms at intervals of 4 months or less. However, false positive screening exams may result in unnecessary surgery. Given the rarity of BWS/HH, a larger, prospective international screening study is necessary to determine if the benefits of screening outweigh the risks.