End stage renal disease in patients with Wilms tumor: results from the National Wilms Tumor Study Group and the United States Renal Data System

WT1-related disorders: more than Denys-Drash syndrome

Historically, specific mutations in WT1 gene have been associated with distinct syndromes based on phenotypic characteristics, including Denys-Drash syndrome (DDS), Frasier syndrome (FS), Meacham syndrome, and WAGR syndrome. DDS is classically defined by the triad of steroid-resistant nephrotic syndrome (SRNS) onset in the first year of life, disorders of sex development (DSD), and a predisposition to Wilms tumor (WT). Currently, a paradigm shift acknowledges a diverse spectrum of presentations beyond traditional syndromic definitions. Consequently, the concept of WT1-related disorders becomes more precise. A genotype-phenotype correlation has been established, emphasizing that the location and type of WT1 mutations significantly influence the clinical presentation, the condition severity, and the chronology of patient manifestations. Individuals presenting with persistent proteinuria, with or without nephrotic syndrome, and varying degrees of kidney dysfunction accompanied by genital malformations should prompt suspicion of WT1 mutations. Recent genetic advances enable a more accurate estimation of malignancy risk in these patients, facilitating a conservative nephron-sparing surgery (NSS) approach in select cases, with a focus on preserving residual kidney function and delaying nephrectomies. Other key management strategies include kidney transplantation and addressing DSD and gonadoblastoma. In summary, recent genetic insights underscore the imperative to implement individualized, integrated, and multidisciplinary management strategies for WT1-related disorders. This approach is pivotal in optimizing patient outcomes and addressing the complexities associated with these diverse clinical manifestations.

Wilms tumor characteristics, surgical management, outcomes, and chronic kidney disease in children with WAGR syndrome: A report from the International WAGR Syndrome Association survey

INTRODUCTION

Children with WAGR (Wilms tumor, aniridia, genitourinary anomalies, and range of development delays) syndrome are predisposed to Wilms tumor (WT) and intrinsic kidney disease. Using the comprehensive International WAGR Syndrome Association (IWSA) survey of children with WAGR syndrome, we analyzed tumor characteristics, treatment and congenital risk factors, and kidney function in children with WAGR and WT.

METHODS

Descriptive statistics were utilized including demographics, treatment strategies, and patient outcomes. Comparisons were made between patients with WAGR and WT to those with WAGR alone. A multivariable logistic regression was completed for risk of developing WT and to identify predictors of chronic kidney disease (CKD).

RESULTS

Sixty-four of 145 children with WAGR developed WT (44.1%). Three relapsed and one died. CKD developed in five children with WAGR without WT (5/81, 6.2%), and in 34 with WAGR and WT (34/64, 28.3%). Children with WAGR and WT were younger (p = .017), and had a greater association with CKD than WAGR children without WT (p < .0001). Two children with WT required hemodialysis, and one underwent kidney transplantation. By univariate analysis, CKD at any stage was associated with complete nephrectomy for the WT surgery (p < .0001), chemotherapy duration greater than 12 months, and three-drug therapy. Upon multivariate analysis, prior nephrectomy was the only significant variable (p = .0002).

CONCLUSIONS

Epidemiological analysis of children with WAGR demonstrated favorable oncologic outcomes, but high rate of early CKD in those who developed WT. Further study of the use of nephron-sparing surgery in children with WAGR and strategies to delay or treat early CKD are needed.

Response of bilateral Wilms tumor to chemotherapy suggests histologic subtype and guides treatment

BACKGROUND

Patients with bilateral Wilms tumor initially receive neoadjuvant chemotherapy to shrink the tumors and increase the likelihood of successful nephron-sparing surgery. Biopsy of poorly responding tumors is often done to better understand therapy resistance. The purpose of this retrospective, single-institution study was to determine whether initial chemotherapy response is associated with tumor histology, potentially obviating the need for biopsy or change in chemotherapy.

METHODS

Patients with synchronous bilateral Wilms tumors who underwent surgery at St Jude Children's Research Hospital from January 2000 to March 2022 were considered for this study. A mixed-effects logistic regression model was used to evaluate the likelihood of the tumor being stromal predominant, as predicted by tumor response to neoadjuvant chemotherapy.

RESULTS

A total of 68 patients were eligible for this study. Tumors that increased in size had an odds ratio of 19.5 (95% confidence interval [CI] = 2.46 to 155.03) for being stromal predominant vs any other histologic subtype. Age at diagnosis was youngest in patients with stromal-predominant tumors, with a mean age of 18.8 (14.1) months compared with all other histologic subtypes (χ2 = 7.05, P = .07). The predictive value of a tumor growing combined with patient aged younger than 18 months for confirming stromal-predominant histology was 85.7% (95% CI = 57.18% to 93.5%).

CONCLUSIONS

Tumors that increased in size during neoadjuvant chemotherapy were most frequently stromal-predominant bilateral Wilms tumor, especially in younger patients. Therefore, nephron-sparing surgery, rather than biopsy, or extension or intensification of neoadjuvant chemotherapy, should be considered for bilateral Wilms tumors that increase in volume during neoadjuvant chemotherapy, particularly in patients aged younger than 18 months.

Hallmark discoveries in the biology of Wilms tumour

The modern study of Wilms tumour was prompted nearly 50 years ago, when Alfred Knudson proposed the 'two-hit' model of tumour development. Since then, the efforts of researchers worldwide have substantially expanded our knowledge of Wilms tumour biology, including major advances in genetics - from cloning the first Wilms tumour gene to high-throughput studies that have revealed the genetic landscape of this tumour. These discoveries improve understanding of the embryonal origin of Wilms tumour, familial occurrences and associated syndromic conditions. Many efforts have been made to find and clinically apply prognostic biomarkers to Wilms tumour, for which outcomes are generally favourable, but treatment of some affected individuals remains challenging. Challenges are also posed by the intratumoural heterogeneity of biomarkers. Furthermore, preclinical models of Wilms tumour, from cell lines to organoid cultures, have evolved. Despite these many achievements, much still remains to be discovered: further molecular understanding of relapse in Wilms tumour and of the multiple origins of bilateral Wilms tumour are two examples of areas under active investigation. International collaboration, especially when large tumour series are required to obtain robust data, will help to answer some of the remaining unresolved questions.

Pediatric Kidney Transplantation: Cancer and Cancer Risk

Children with end-stage kidney disease (ESKD) face a lifetime of complex medical care, alternating between maintenance chronic dialysis and kidney transplantation. Kidney transplantation has emerged as the optimal treatment of ESKD for children and provides important quality of life and survival advantages. Although transplantation is the preferred therapy, lifetime exposure to immunosuppression among children with ESKD is associated with increased morbidity, including an increased risk of cancer. Following pediatric kidney transplantation, cancer events occurring during childhood or young adulthood can be divided into two broad categories: post-transplant lymphoproliferative disorders and non-lymphoproliferative solid tumors. This review provides an overview of cancer incidence, types, outcomes, and preventive strategies in this population.

Wilms' tumor gene 1: lessons from the interface between kidney development and cancer

In 1990, mutations of the Wilms' tumor-1 gene (WT1), encoding a transcription factor in the embryonic kidney, were found in 10-15% of Wilms' tumors; germline WT1 mutations were associated with hereditary syndromes involving glomerular and reproductive tract dysplasia. For more than three decades, these discoveries prompted investigators to explore the embryonic role of WT1 and the mechanisms by which loss of WT1 leads to malignant transformation. Here, we discuss how alternative splicing of WT1 generates isoforms that act in a context-specific manner to activate or repress target gene transcription. WT1 also regulates posttranscriptional regulation, alters the epigenetic landscape, and activates miRNA expression. WT1 functions at multiple stages of kidney development, including the transition from resting stem cells to committed nephron progenitor, which it primes to respond to WNT9b signals from the ureteric bud. WT1 then drives nephrogenesis by activating WNT4 expression and directing the development of glomerular podocytes. We review the WT1 mutations that account for Denys-Drash syndrome, Frasier syndrome, and WAGR syndrome. Although the WT1 story began with Wilms' tumors, an understanding of the pathways that link aberrant kidney development to malignant transformation still has some important gaps. Loss of WT1 in nephrogenic rests may leave these premalignant clones with inadequate DNA repair enzymes and may disturb the epigenetic landscape. Yet none of these observations provide a complete picture of Wilms' tumor pathogenesis. It appears that the WT1 odyssey is unfinished and still holds a great deal of untilled ground to be explored.

Surgery in Bilateral Wilms Tumor-A Single-Center Experience

The treatment of bilateral Wilms tumors (BWT) involves curing the cancer, preserving long-term renal function, and maintaining a good quality of life. Established methods for achieving these goals include preoperative chemotherapy and nephron-sparing surgery (NSS). This study aimed to evaluate the experience of a single institution in treating patients with BWT. We analyzed cases of BWT treated at the Pediatric Oncology Institute-GRAACC-Federal University of São Paulo over a period of 35 years. Bleeding control was performed with manual compression of the renal parenchyma. Thirty-three patients were included in the study. Thirty cases were synchronous tumors. The mean age at diagnosis was 30.4 months (±22 m) and 66.7% were girls. The median follow-up period was 83 months. Neoadjuvant chemotherapy was the primary approach in most patients (87.9%), with a simultaneous upfront surgical approach performed in 84.8%. Most patients underwent bilateral NSS (70.4%). There were no early complications in this series, but 39.4% had clinical complications. The five-year survival rate was 76%. Therefore, it is clear that the surgical approach to BWT plays a crucial role in achieving good outcomes. However, it is difficult to standardize surgical techniques and technology may have the potential to enhance safety.

Long-term nephrotoxicity in irradiated pediatric kidney tumor survivors: A systematic review

OBJECTIVE

Nephrotoxicity can occur as a side effect after treatment for kidney tumor in childhood. The use of radiotherapy (RT) has a potential additional effect.

METHODS

A systematic electronic literature search that combined childhood kidney cancer with different treatments and nephrotoxicity terms was performed in EMBASE. Studies were included based on the reporting of nephrotoxicity occurrence after treatment for kidney tumor during pediatric age, with 75% of participants being under the age of 25 years at the time of diagnosis, and having been treated with any type of kidney surgery, chemotherapy, and/or RT.

RESULTS

A pooled analysis did not show significant difference in estimated glomerular filtration rate between the group of patients who received RT compared with the group treated without RT (SMD -0.11 [95% CI -1.07-0.84] p = .733).

CONCLUSION

The current literature suggests that the use of RT does not have a significant impact on the decline of kidney function as independent factor.

Children's Oncology Group's 2023 blueprint for research: Renal tumors

Every year, approximately 600 infants, children, and adolescents are diagnosed with renal cancer in the United States. In addition to Wilms tumor (WT), which accounts for about 80% of all pediatric renal cancers, clear cell sarcoma of the kidney, renal cell carcinoma, malignant rhabdoid tumor, as well as more rare cancers (other sarcomas, rare carcinomas, lymphoma) and benign tumors can originate within the kidney. WT itself can be divided into favorable histology (FHWT), with a 5-year overall survival (OS) exceeding 90%, and anaplastic histology, with 4-year OS of 73.7%. Outcomes of the other pediatric renal cancers include clear cell sarcoma (5-year OS: 90%), malignant rhabdoid tumor (5-year OS: 10% for stages 3 and 4), and renal cell carcinoma (4-year OS: 84.8%). Recent clinical trials have identified novel biological prognostic markers for FHWT, and a series of Children's Oncology Group (COG) trials have demonstrated improving outcomes with therapy modification, and opportunities for further care refinement.

Late Health Outcomes Among Survivors of Wilms Tumor Diagnosed Over Three Decades: A Report From the Childhood Cancer Survivor Study

PURPOSE

To evaluate long-term morbidity and mortality among unilateral, nonsyndromic Wilms tumor (WT) survivors according to conventional treatment regimens.

METHODS

Cumulative incidence of late mortality (≥ 5 years from diagnosis) and chronic health conditions (CHCs) were evaluated in WT survivors from the Childhood Cancer Survivor Study. Outcomes were evaluated by treatment, including nephrectomy combined with vincristine and actinomycin D (VA), VA + doxorubicin + abdominal radiotherapy (VAD + ART), VAD + ART + whole lung radiotherapy, or receipt of ≥ 4 chemotherapy agents.

RESULTS

Among 2,008 unilateral WT survivors, 142 deaths occurred (standardized mortality ratio, 2.9, 95% CI, 2.5 to 3.5; 35-year cumulative incidence of death, 7.8%, 95% CI, 6.3 to 9.2). The 35-year cumulative incidence of any grade 3-5 CHC was 34.1% (95% CI, 30.7 to 37.5; rate ratio [RR] compared with siblings 3.0, 95% CI, 2.6 to 3.5). Survivors treated with VA alone had comparable risk for all-cause late mortality relative to the general population (standardized mortality ratio, 1.0; 95% CI, 0.5 to 1.7) and modestly increased risk for grade 3-5 CHCs compared with siblings (RR, 1.5; 95% CI, 1.1 to 2.0), but remained at increased risk for intestinal obstruction (RR, 9.4; 95% CI, 3.9 to 22.2) and kidney failure (RR, 11.9; 95% CI, 4.2 to 33.6). Magnitudes of risk for grade 3-5 CHCs, including intestinal obstruction, kidney failure, premature ovarian insufficiency, and heart failure, increased by treatment group intensity.

CONCLUSION

With approximately 40% of patients with newly diagnosed WT currently treated with VA alone, the burden of late mortality/morbidity in future decades is projected to be lower than that for survivors from earlier eras. Nevertheless, the risk of late effects such as intestinal obstruction and kidney failure was elevated across all treatment groups, and there was a dose-dependent increase in risk for all grade 3-5 CHCs by treatment group intensity.

Development and Validation of a Prediction Model for Kidney Failure in Long-Term Survivors of Childhood Cancer

PURPOSE

Kidney failure is a rare but serious late effect following treatment for childhood cancer. We developed a model using demographic and treatment characteristics to predict individual risk of kidney failure among 5-year survivors of childhood cancer.

METHODS

Five-year survivors from the Childhood Cancer Survivor Study (CCSS) without history of kidney failure (n = 25,483) were assessed for subsequent kidney failure (ie, dialysis, kidney transplantation, or kidney-related death) by age 40 years. Outcomes were identified by self-report and linkage with the Organ Procurement and Transplantation Network and the National Death Index. A sibling cohort (n = 5,045) served as a comparator. Piecewise exponential models accounting for race/ethnicity, age at diagnosis, nephrectomy, chemotherapy, radiotherapy, congenital genitourinary anomalies, and early-onset hypertension estimated the relationships between potential predictors and kidney failure, using area under the curve (AUC) and concordance (C) statistic to evaluate predictive power. Regression coefficient estimates were converted to integer risk scores. The St Jude Lifetime Cohort Study and the National Wilms Tumor Study served as validation cohorts.

RESULTS

Among CCSS survivors, 204 developed late kidney failure. Prediction models achieved an AUC of 0.65-0.67 and a C-statistic of 0.68-0.69 for kidney failure by age 40 years. Validation cohort AUC and C-statistics were 0.88/0.88 for the St Jude Lifetime Cohort Study (n = 8) and 0.67/0.64 for the National Wilms Tumor Study (n = 91). Risk scores were collapsed to form statistically distinct low- (n = 17,762), moderate- (n = 3,784), and high-risk (n = 716) groups, corresponding to cumulative incidences in CCSS of kidney failure by age 40 years of 0.6% (95% CI, 0.4 to 0.7), 2.1% (95% CI, 1.5 to 2.9), and 7.5% (95% CI, 4.3 to 11.6), respectively, compared with 0.2% (95% CI, 0.1 to 0.5) among siblings.

CONCLUSION

Prediction models accurately identify childhood cancer survivors at low, moderate, and high risk for late kidney failure and may inform screening and interventional strategies.

Impact of Time to Surgery on Outcome in Wilms Tumor Treated with Preoperative Chemotherapy

(1) Background: Wilms tumor (WT) treated preoperatively is cured in over 90% of cases. However, how long preoperative chemotherapy can be given is unknown. (2) Methods: 2561/3030 patients with WT (age < 18 years) treated between 1989 and 2022 according to SIOP-9/GPOH, SIOP-93-01/GPOH, and SIOP-2001/GPOH are retrospectively analyzed to assess the risk of time to surgery (TTS) for relapse-free survival (RFS) and overall survival (OS). (3) Results: TTS was calculated for all surgeries, with the mean being 39 days (38.5 ± 12.5) for unilateral tumors (UWT) and 70 days (69.9 ± 32.7) for bilateral disease (BWT). Relapse occurred in 347 patients, of which 63 (2.5%) were local, 199 (7.8%) were metastatic, and 85 (3.3%) were combined. Moreover, 184 patients (7.2%) died, 152 (5.9%) due to tumor progression. In UWT, recurrences and mortality are independent of TTS. For BWT without metastases at diagnosis, the incidence of recurrence is less than 18% up to 120 days and increases to 29% after 120 days, and to 60% after 150 days. The risk of relapse (Hazard Ratio) adjusted for age, local stage, and histological risk group increases to 2.87 after 120 days (CI 1.19-7.95, p = 0.022) and to 4.62 after 150 days (CI 1.17-18.26, p = 0.029). In metastatic BWT, no influence of TTS is detected. (4) Conclusions: The length of preoperative chemotherapy has no negative impact on RFS or OS in UWT. In BWT without metastatic disease, surgery should be performed before day 120, as the risk of recurrence increases significantly thereafter.

Meta-Analysis on Long-Term Outcomes of Pediatric Renal Cancer Survivors Following COG and SIOP Protocols

BACKGROUND

 Pediatric renal cancer survivors have higher rate of chronic renal disease and hypertension. These patients have similar survival rates when treated according to either Children's Oncology Group (COG) or International Society of Pediatric Oncology (SIOP) protocols. We aimed to compare the late outcome of these two approaches.

METHODS

 We performed a meta-analysis of all studies from 2000 to 2021; database search using keywords: long-term outcomes OR late effects, nephrectomy, pediatric renal cancer. For each protocol, data were collected, and the "pooled" outcomes were compared. Continuous and dichotomous variables were obtained with a 95% odds ratio.

RESULTS

 Sixteen studies with a total of 715 pediatric renal cancer survivors were analyzed. The mean follow-up time was 17.4 (standard deviation 5.6) years. Reduced renal function and hypertension were the most encountered long-term complications. The mean estimated glomerular filtration rate was similar in both protocols (101.62 vs. 101.70 mL/min/1.73 m²), while the prevalence of hypertension was 23% in COG and 10% in SIOP. The prevalence of secondary malignancy was 1.1% in COG and 6.7% in SIOP (1.1% vs. 6.7%, p ≤ 0.001). Chronic kidney disease was similar in both groups.

CONCLUSION

 A high prevalence of hypertension was observed among pediatric renal cancer survivors, as well as an increased risk of a secondary tumor. These results emphasize the importance of long-term follow-up into adulthood, to promptly diagnose any long-term side effects of the treatment. Thanks to the increased overall survival, future protocols will pay attention to the reduction of long-term sequelae.

Ex vivo tumor dissection followed by kidney autotransplantation in bilateral wilms tumor

INTRODUCTION

Successful management of bilateral Wilm's tumor (BWT) involves a radical resection while preserving enough normal kidney tissue. Nephron-sparing surgery often results in an R1/R2 resection with a high recurrence rate in children with huge or multiple tumors, or tumors proximity to the renal hilum. In contrast, kidney autotransplantation can completely resect the tumor while maintaining homeostasis and preserving the patient's healthy kidney tissues.

METHODS

We summarized the clinical data of 8 synchronous BWT patients who underwent kidney autotransplantation at the First Affiliated Hospital of Sun Yat-sen University from 2018 to 2020. Ex vivo tumor resection and kidney autotransplantions were performed on 11 kidneys. The baseline characteristics, perioperative management, and survival status were reported.

RESULTS

Nephron-sparing surgeries were performed on 5 kidneys in vivo. Among all the 8 patients, six of them (75%) received staged operation and the other 2 patients (25%) received single-stage operation. No residual tumors were found on the postoperative imaging in all the 8 patients. In total, 6 (75%) patients occurred complications after the autotransplantation, among which, 2 (33.3%) patients had complication of Clavien-Dindo grade IIIa, and 4 (66.7%) patients had complication of grade < 3. During the 38 months of follow-up, 87.5% (7/8) of patients were tumor-free survival with normal renal function. One patient died from renal failure without tumor recurrence.

DISCUSSION

Therefore, our study indicated that autologous kidney transplantation can be an option for patients with complex BWT if the hospital's surgical technique and perioperative management conditions are feasible.

Bench surgery with autotransplantation for bilateral Wilms tumor-A feasible technique for renal sinus invasion

Purpose

Bilateral Wilms tumor (BWT) with renal sinus invasion requires extremely difficult surgical care. This study presents an alternative strategy for tumor removal while at the same time preserving the renal parenchyma.

Materials and methods

In total, 9 cases of synchronous BWT were admitted to our hospital between May 2016 to Aug 2020. We retrospectively reviewed the clinical data, surgical technique, and functional and oncological outcomes of these cases.

Results

The 9 cases included 3 males and 6 females, with a median age of 12 months at surgery (range 7-40). A total of 14 kidney units had renal sinus invasion (77.8%), whereas multifocal neoplasms were observed in 7 units (38.9%). The local stage distribution revealed 1 kidney with stage I, 10 kidneys with stage II, and 7 kidneys with stage III. Nephron-sparing surgery was performed on 15 kidney units (83.3%), among which 13 (72.2%) underwent bench surgery with autotransplantation (BS-AT), whereas 2 (11.1%) were subjected to tumor enucleation in vivo. Urinary leakage was the most prevalent postoperative complication. We observed negative margins. During the mean follow-up of 28.4 months, 2 patients (22.2%) succumbed from sepsis and renal failure, respectively, whereas the other 7 (77.8%) survived without recurrence. Survivors experienced an estimated glomerular filtration rate of 81 ± 15.4 ml/(min × 1.73 m²). The endpoint renal volume of 9 renal units receiving BS-AT significantly increased (P = 0.02).

Conclusions

In summary, the surgical management of bilateral Wilms tumor requires meticulous operative approach and technique. Besides, BS-AT provides a viable alternative to nephron-sparing surgery for BWT patients with renal sinus invasion.

[Tumor predisposition syndromes and nephroblastoma : Early diagnosis with imaging]

CLINICAL/METHODICAL ISSUE

The Beckwith-Wiedemann spectrum (BWSp) as well as the WT1-related syndromes, Denys-Drash syndrome (DDS) and WAGR spectrum (Wilms tumor, Aniridia, genitourinary anomalies and a range of developmental delays) are tumor predisposition syndromes (TPS) of Wilms tumor (WT). Patients with associated TPS are at higher risk of developing chronic kidney disease and bilateral and metachronous tumors as well as nephrogenic rests.

STANDARD RADIOLOGICAL METHODS

Standard imaging diagnostics for WT include renal ultrasound and magnetic resonance imaging (MRI). In the current renal tumor studies Umbrella SIOP-RTSG 2016 and Randomet 2017, thoracic computed tomography (CT) is also recommended as standard. Positron emission tomography (PET)-CT and whole-body MRI, on the other hand, are not part of routine diagnostics.

METHODOLOGICAL INNOVATIONS

In recent publications, renal ultrasound is recommended every 3 months until the age of 7 years in cases of clinical suspicion or molecularly proven TPS.

PERFORMANCE

Patients with TPS and regular renal ultrasounds have smaller tumor volumes and lower tumor stages at WT diagnosis than patients without such a screening. This allows a reduction of therapy intensity and facilitates the performance of nephron sparing surgery, which is prognostically relevant especially in bilateral WT.

ACHIEVEMENTS

Early diagnosis of WT in the context of TPS ensures the greatest possible preservation of healthy and functional renal tissue. Standardized screening by regular renal ultrasounds should therefore be firmly established in clinical practice.

PRACTICAL RECOMMENDATIONS

The initial diagnosis of TPS is clinical and requires a skilled and attentive examiner in the presence of sometimes subtle clinical manifestations, especially in the case of BWSp. Clinical diagnosis should be followed by genetic testing, which should then be followed by sonographic screening.

Increased risk for kidney sequelae surrogates in survivors of Wilms tumor

BACKGROUND

There is evidence of increased risk of hypertension, albuminuria, and development of chronic kidney disease (CKD) in long-term follow-up of survivors of Wilms tumor (WT). However, most studies were conducted in heterogeneous groups, including patients with solitary kidney. In addition, little is known about tubular dysfunction. This study aimed to investigate kidney sequelae, including CKD development, hypertension, and glomerular and tubular damage in WT survivors.

METHODS

This cross-sectional, single-center study included 61 patients treated for WT. Surrogates for kidney sequelae were defined as presence of at least one of the following: decrease in GFR for CKD, hypertension detected by ambulatory blood pressure monitoring, albuminuria (albumin-to-creatinine ratio [ACR] > 30 mg/g), or increase in at least one tubular biomarker (beta-2-microglobulin, neutrophil gelatinase-associated lipocalin, kidney injury marker-1, and liver fatty acid-binding protein) in 24-h urine.

RESULTS

Median age of patients was 11.7 years, with median follow-up of 8.8 years. Thirty-eight patients (62%) had at least one surrogate for kidney sequelae. Twenty-four patients (39%) had CKD, 14 patients (23%) had albuminuria, 12 patients (21%) had hypertension, and 11 patients (18%) had tubular damage. Urine ACR was significantly higher in patients with advanced tumor stage and patients with nephrotoxic therapy than their counterparts (p < 0.05), but neither eGFR nor tubular biomarkers showed any association with tumor- or treatment-related factors.

CONCLUSIONS

A considerable number of patients with WT have kidney sequelae, especially early-stage CKD with a high prevalence. Albuminuria emerges as a marker associated with tumor stages and nephrotoxic treatment. A higher resolution version of the Graphical abstract is available as Supplementary information.

Photodynamic Therapy in Complex Therapy of Retroperitoneal Tumors in Children

During the period from 2009 to 2021, 93 patients aged 0–11 years (48 boys and 45 girls) with retroperitoneal tumors were treated. There were 66 patients with nephroblastoma and 27 patients with adrenal neuroblastoma among them. As per treatment strategies, the patients were separated into two groups: the control group and the study group. The control group (comparison) received therapy according to the protocols, whereas the study group consisted of patients who received photodynamic therapy (PDT) in addition to the standard treatment. The control group consists of 47 patients with retroperitoneal tumors, including 35 patients with nephroblastoma and 12 patients with adrenal neuroblastoma. The study group included 46 children: 31 patients with nephroblastoma and 15 patients with adrenal neuroblastoma. The 5-year survival rate in the control group was 74.5%, and it was 91.3% in the study group (p = 0.030). Recurrent tumors developed in 14.9% of the patients in the control group, while in the study group, relapse occurred in 8.7% of the patients (p = 0.357). The PDT used in this study for treatment of retroperitoneal tumors improves the results of surgical treatment. It also appreciably increases the survival rate of patients with retroperitoneal tumors. Overall, PDT is a hopeful antitumor approach and can be effectively used in the complex therapy of retroperitoneal tumors in children.

Kidney disease in very long-term survivors of Wilms tumor: A nationwide cohort study with sibling controls

BACKGROUND

Survival after Wilms tumor has significantly increased and focus on late effects has become increasingly important. However, knowledge about long-term renal function in survivors of Wilms tumor is missing. Our aim was to investigate evidence of kidney disease in 20- or more-year survivors of Wilms tumor in a clinical setting, with siblings as comparisons.

METHODS

In this cross-sectional study, we established a cohort of Danish 20-plus-year survivors of Wilms tumor and siblings as controls. Participants answered a comprehensive health questionnaire supplemented by measurements of estimated glomerular filtration rate (eGFR), urine albumin-to-creatinine ratio, and blood pressure and were categorized according to the chronic kidney disease classification. Multiple linear regression analysis, taking family membership into account, was used to describe the differences in eGFR. Logistic regression analysis was performed to describe risk factors for the development of kidney disease.

RESULTS

We included 99 survivors of Wilms tumor and 38 sibling controls with a median of 37 years of follow-up. The eGFR of Wilms tumor survivors was 13 ml/min/1.73 m² (95% CI -20; -5) lower when compared to sibling control. Evidence of kidney disease, with risk factors as hypertension and diabetes, was found in 19% of the Wilms tumor survivors and 2% developed end-stage renal disease. Ninety-two percent of the Wilms tumor survivors had an eGFR >60 ml/min/1.73² .

CONCLUSION

Long-term Wilms tumor survivors have on average a significantly decreased renal function along with the increased prevalence of kidney disease and end-stage renal disease when compared to sibling controls. Still, most survivors had kidney function within the normal range.

Long-term kidney function in children with Wilms tumour and constitutional WT1 pathogenic variant

BACKGROUND

Wilms tumour (WT) survivors, especially patients with associated syndromes or genitourinary anomalies due to constitutional WT1 pathogenic variant, have increased risk of kidney failure. We describe the long-term kidney function in children with WT and WT1 pathogenic variant to inform the surgical strategy and oncological management of such complex children.

METHODS

Retrospective analysis of patients with WT and constitutional WT1 pathogenic variant treated at a single centre between 1993 and 2016, reviewing genotype, phenotype, tumour histology, laterality, treatment, patient survival, and kidney outcome.

RESULTS

We identified 25 patients (60% male, median age at diagnosis 14 months, range 4-74 months) with WT1 deletion (4), missense (2), nonsense (8), frameshift (7), or splice site (4) pathogenic variant. Thirteen (52%) had bilateral disease, 3 (12%) had WT-aniridia, 1 had incomplete Denys-Drash syndrome, 11 (44%) had genitourinary malformation, and 10 (40%) had no phenotypic anomalies. Patient survival was 100% and 3 patients were in remission after relapse at median follow-up of 9 years. Seven patients (28%) commenced chronic dialysis of which 3 were after bilateral nephrectomies. The overall kidney survival for this cohort as mean time to start of dialysis was 13.38 years (95% CI: 10.3-16.4), where 7 patients experienced kidney failure at a median of 5.6 years. All of these 7 patients were subsequently transplanted. In addition, 2 patients have stage III and stage IV chronic kidney disease and 12 patients have albuminuria and/or treatment with ACE inhibitors. Four patients (3 frameshift; 1 WT1 deletion) had normal blood pressure and kidney function without proteinuria at follow-up from 1.5 to 12 years.

CONCLUSIONS

Despite the known high risk of kidney disease in patients with WT and constitutional WT1 pathogenic variant, nearly two-thirds of patients had sustained native kidney function, suggesting that nephron-sparing surgery (NSS) should be attempted when possible without compromising oncological risk. Larger international studies are needed for accurate assessment of WT1genotype-kidney function phenotype correlation.

Virtual Resection: A New Tool for Preparing for Nephron-Sparing Surgery in Wilms Tumor Patients

Nephron-sparing surgery (NSS) in Wilms tumor (WT) patients is a surgically challenging procedure used in highly selective cases only. Virtual resections can be used for preoperative planning of NSS to estimate the remnant renal volume (RRV) and to virtually mimic radical tumor resection. In this single-center evaluation study, virtual resection for NSS planning and the user experience were evaluated. Virtual resection was performed in nine WT patient cases by two pediatric surgeons and one pediatric urologist. Pre- and postoperative MRI scans were used for 3D visualization. The virtual RRV was acquired after performing virtual resection and a questionnaire was used to assess the ease of use. The actual RRV was derived from the postoperative 3D visualization and compared with the derived virtual RRV. Virtual resection resulted in virtual RRVs that matched nearly perfectly with the actual RRVs. According to the questionnaire, virtual resection appeared to be straightforward and was not considered to be difficult. This study demonstrated the potential of virtual resection as a new planning tool to estimate the RRV after NSS in WT patients. Future research should further evaluate the clinical relevance of virtual resection by relating it to surgical outcome.

Dimethylarginines in Children after Anti-Neoplastic Treatment

Background and Objectives: According to a recent Cochrane systematic review, renal impairment can develop in 0–84% of childhood cancer survivors in the future. The renal function impairment in this patient group can be related to nephrectomy, nephrotoxic agents therapy, abdominal radiotherapy, and combinations of these treatment methods. In this study, in a population of patients after anti-neoplastic therapy, with particular emphasis on patients after Wilms’ tumour treatment, we compared new substances which play role in the chronic kidney disease (CKD) pathogenesis (asymmetric dimethylarginine—ADMA, symmetric dimethylarginine—SDMA) with standard renal function markers (e.g., creatinine and cystatin C in serum, creatinine in urine, etc.) to assess the usefulness of the former. Materials and Methods: Eighty-four children, without CKD, bilateral kidney tumours, congenital kidney defects, or urinary tract infections, with a minimum time of 1 year after ending anti-neoplastic treatment, aged between 17 and 215 months, were divided into three groups: group 1—patients after nephroblastoma treatment (n = 21), group 2—after other solid tumours treatment (n = 44), and group 3—after lymphoproliferative neoplasms treatment (n = 19). The patients’ medical histories were taken and physical examinations were performed. Concentrations of blood urea nitrogen (BUN), creatinine, cystatin C, C-reactive protein (CRP), ADMA, and SDMA in blood and albumin in urine were measured, and a general urine analysis was performed. The SDMA/ADMA ratio, albumin–creatine ratio, and estimated glomerular filtration rate (eGFR) were calculated. eGFR was estimated by three equations recommended to the paediatric population by the KDIGO from 2012: the Schwartz equation (eGFR1), equation with creatinine and urea nitrogen (eGFR2), and equation with cystatin C (eGFR3). Results: Both the eGFR1 and eGFR2 values were significantly lower in group 1 than in group 3 (eGFR1: 93.3 (83.1–102.3) vs. 116.5 (96.8–126.9) mL/min/1.73 m², p = 0.02; eGFR2: 82.7 (±14.4) vs. 94.4 (±11.9) mL/min/1.73 m², p = 0.02). Additionally, there were weak positive correlations between SDMA and creatinine (p < 0.05, r = 0.24), and cystatin C (p < 0.05, r = 0.32) and weak negative correlations between SDMA and eGFR1 (p < 0.05, r = −0.25), eGFR2 (p < 0.05, r = −0.24), and eGFR3 (p < 0.05, r = −0.32). Conclusions: The usefulness of ADMA and SDMA in the diagnosis of renal functional impairment should be assessed in further studies. eGFR, calculated according to equations recommended for children, should be used in routine paediatric practice.

Multidisciplinary Treatment Strategies for Wilms Tumor: Recent Advances, Technical Innovations and Future Directions

Significant progress has been made in the management of Wilms tumor (WT) in recent years, mostly as a result of collaborative efforts and the implementation of protocol-driven, multimodal therapy. This article offers a comprehensive overview of current multidisciplinary treatment strategies for WT, whilst also addressing recent technical innovations including nephron-sparing surgery (NSS) and minimally invasive approaches. In addition, surgical concepts for the treatment of metastatic disease, advances in tumor imaging technology and potentially prognostic biomarkers will be discussed. Current evidence suggests that, in experienced hands and selected cases, laparoscopic radical nephrectomy and laparoscopic-assisted partial nephrectomy for WT may offer the same outcome as the traditional open approach. While NSS is the standard procedure for bilateral WT, NSS has evolved as an alternative technique in patients with smaller unilateral WT and in cases with imminent renal failure. Metastatic disease of the lung or liver that is associated with WT is preferably treated with a three-drug chemotherapy and local radiation therapy. However, surgical sampling of lung nodules may be advisable in persistent nodules before whole lung irradiation is commenced. Several tumor markers such as loss of heterozygosity of chromosomes 1p/16q, 11p15 and gain of function at 1q are associated with an increased risk of recurrence or a decreased risk of overall survival in patients with WT. In summary, complete resection with tumor-free margins remains the primary surgical aim in WT, while NSS and minimally invasive approaches are only suitable in a subset of patients with smaller WT and low-risk disease. In the future, advances in tumor imaging technology may assist the surgeon in defining surgical resection margins and additional biomarkers may emerge as targets for development of new diagnostic tests and potential therapies.

Spectrum of Clinical Manifestations in Children With WT1 Mutation: Case Series and Literature Review

BACKGROUND

Mutations of the Wilms tumor suppressor-1 gene (WT1) are associated with life-threatening glomerulopathy, disorders of sexual development, Wilm's tumor, and gonadal malignancies. Our objectives were to describe the clinical presentations, age of progression, and onset of complications of WT1 mutation through a case series and literature review.

METHODS

A retrospective study included all patients followed at the University of Miami/Holtz Children's Hospital from January 2000 to December 2020 with a diagnosis of WT1 mutation. A literature review of WT1 mutation cases was analyzed for clinical manifestations, karyotype, and long-term outcomes.

RESULTS

The WT1 mutation was identified in 9 children, median age at presentation of 0.9 years (range 1 week to 7 years). A total of four had female phenotypes, and 5 had abnormalities of male external genitalia, while all had XY karyotypes. All progressed to end-stage kidney disease (ESKD) and received a kidney transplant at a median age of 5 years (1.5-15 years). During a median time of follow-up of 9 years (range 2-28 years), there were 2 allograft losses after 7 and 10 years and no evidence of post-transplant malignancy. From 333 cases identified from the literature review, the majority had female phenotype 66% (219/333), but the predominant karyotype was XY (55%, 183/333). Of the female phenotypes, 32% (69/219) had XY sex reversal. Wilm's tumor occurred in 24%, predominantly in males with gonadal anomalies.

CONCLUSIONS

Early recognition of WT1 mutation is essential for comprehensive surveillance of potential malignancy, avoidance of immunosuppressants for glomerulopathy, and establishing long-term multidisciplinary management.

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

Objectives

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

Materials and Methods

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

Results

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

Conclusions

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

Bilateral Renal Tumors in Children: The First 5 Years' Experience of National Centralization in The Netherlands and a Narrative Review of the Literature

Survival of unilateral Wilms tumors (WTs) is exceeding 90%, whereas bilateral WTs have an inferior outcome. We evaluated all Dutch patients with bilateral kidney tumors, treated in the first five years of national centralization and reviewed relevant literature. We identified 24 patients in our center (2015–2020), 23 patients had WT/nephroblastomatosis and one renal cell carcinoma. Patients were treated according to SIOP-RTSG protocols. Chemotherapy response was observed in 26/34 WTs. Nephroblastomatosis lesions were stable (n = 7) or showed response (n = 18). Nephron-sparing surgery was performed in 11/22 patients undergoing surgery (n = 2 kidneys positive margins). Local stage in 20 patients with ≥1 WT revealed stage I (n = 7), II (n = 4) and III (n = 9). Histology was intermediate risk in 15 patients and high risk in 5. Three patients developed a WT in a treated nephroblastomatosis lesion. Two of 24 patients died following toxicity and renal failure, i.e., respectively dialysis-related invasive fungal infection and septic shock. Genetic predisposition was confirmed in 18/24 patients. Our literature review revealed that knowledge is scarce on bilateral renal tumor patients with metastases and that radiotherapy seems important for local stage III patients. Bilateral renal tumors are a therapeutic challenge. We describe management and outcome in a national expert center and summarized available literature, serving as baseline for further improvement of care.

Wilms tumour

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

Systematic review of the immunological landscape of Wilms tumors

Results of immunotherapy in childhood solid cancer have been so far, with the exception of neuroblastoma, quite disappointing. Lack of knowledge of the immune contexture of these tumors may have contributed to the failure of immunotherapies so far. Here, we systematically reviewed the literature regarding the immunology of Wilms tumor (WT), one of the most frequent pediatric solid tumors of the abdomen. In Wilms tumor patients the high cure rate of >90%, achieved by the combination of surgery and radio-chemotherapy, is at the expense of a high early and late toxicity. Moreover, treatment-resistant entities, such as diffuse anaplastic tumors or recurrent disease, still pose unsolved clinical problems. Successful immunotherapy could represent a novel and possibly less-toxic treatment option. Employing the PRISMA (Preferred Reporting Items for Systematic Review and Meta-Analysis) method of literature search, we analyzed the current knowledge of the immunological landscape of Wilms tumors in terms of tumor microenvironment, prognostic implications of single biomarkers, and immunotherapy response.

Outcomes of kidney injury including dialysis and kidney transplantation in pediatric oncology and hematopoietic cell transplant patients

Pediatric oncology and hematopoietic cell transplant (HCT) patients are susceptible to both acute kidney injury (AKI) and chronic kidney disease (CKD). The etiologies of AKI vary but include tumor infiltration, radiation, drug-induced toxicity, and fluid and electrolyte abnormalities including tumor lysis syndrome. HCT patients can also have additional complications such as sinusoidal obstructive syndrome, graft-versus-host disease, or thrombotic microangiopathy. For patients with severe AKI requiring dialysis, multiple modalities can be used successfully, although continuous kidney replacement therapy (CKRT) is often the principal modality for critically ill patients. While increasing numbers of pediatric cancer and HCT patients are now surviving long term, they remain at risk for a number of chronic medical conditions, including CKD. Certain high-risk patients, due to underlying risk factors or treatment-related complications, eventually develop kidney failure and may require kidney replacement therapies. Management of co-morbidities and complications associated with kidney failure, including use of erythropoietin for anemia and potential need for ongoing cancer-related treatment while on dialysis, is an additional consideration in this patient population. Kidney transplantation can be successfully performed in pediatric cancer survivors, although additional features such as specific cancer diagnosis and duration of remission should be considered.

Late-onset kidney failure in survivors of childhood cancer: a report from the Childhood Cancer Survivor Study

BACKGROUND

The incidence of and risk factors for late-onset kidney failure among survivors over the very long term remains understudied.

MATERIALS AND METHODS

A total of 25,530 childhood cancer survivors (median follow-up 22.3 years, interquartile range 17.4-28.8) diagnosed between 1970 and 1999, and 5045 siblings from the Childhood Cancer Survivor Study were assessed for self-reported late-onset kidney failure, defined as dialysis, renal transplantation, or death attributable to kidney disease. Piecewise exponential models evaluated associations between risk factors and the rate of late-onset kidney failure.

RESULTS

A total of 206 survivors and 10 siblings developed late-onset kidney failure, a 35-year cumulative incidence of 1.7% (95% confidence interval [CI] = 1.4-1.9) and 0.2% (95% confidence interval [CI] = 0.1-0.4), respectively, corresponding to an adjusted rate ratio (RR) of 4.9 (95% CI = 2.6-9.2). High kidney dose from radiotherapy (≥15Gy; RR = 4.0, 95% CI = 2.1-7.4), exposure to high-dose anthracycline (≥250 mg/m2; RR = 1.6, 95% CI = 1.0-2.6) or any ifosfamide chemotherapy (RR = 2.6, 95% CI = 1.2-5.7), and nephrectomy (RR = 1.9, 95% CI = 1.0-3.4) were independently associated with elevated risk for late-onset kidney failure among survivors. Survivors who developed hypertension, particularly in the context of prior nephrectomy (RR = 14.4, 95% CI = 7.1-29.4 hypertension with prior nephrectomy; RR = 5.9, 95% CI = 3.3-10.5 hypertension without prior nephrectomy), or diabetes (RR = 2.2, 95%CI = 1.2-4.2) were also at elevated risk for late-onset kidney failure.

CONCLUSIONS

Survivors of childhood cancer are at increased risk for late-onset kidney failure. Kidney dose from radiotherapy ≥15 Gy, high-dose anthracycline, any ifosfamide, and nephrectomy were associated with increased risk of late-onset kidney failure among survivors. Successful diagnosis and management of modifiable risk factors such as diabetes and hypertension may mitigate the risk for late-onset kidney failure. The association of late-onset kidney failure with anthracycline chemotherapy represents a novel finding that warrants further study.

WT1 Pathogenic Variants are Associated with a Broad Spectrum of Differences in Sex Development Phenotypes and Heterogeneous Progression of Renal Disease

Wilms' tumor suppressor gene 1 (WT1) plays an essential role in urogenital and kidney development. Heterozygous germline pathogenic allelic variants of WT1 have been classically associated with Denys-Drash syndrome (DDS) and Frasier syndrome (FS). Usually, exonic pathogenic missense variants in the zinc finger region are the cause of DDS, whereas pathogenic variants affecting the canonic donor lysine-threonine-serine splice site in intron 9 cause FS. Phenotypic overlap between WT1 disorders has been frequently observed. New WT1 variant-associated phenotypes, such as 46,XX testicular/ovarian-testicular disorders of sex development (DSD) and primary ovarian insufficiency, have been reported. In this report, we describe the phenotypes and genotypes of 7 Brazilian patients with pathogenic WT1 variants. The molecular study involved Sanger sequencing and massively parallel targeted sequencing using a DSD-associated gene panel. Six patients (5 with a 46,XY karyotype and 1 with a 46,XX karyotype) were initially evaluated for atypical genitalia, and a 46,XY patient with normal female genitalia sought medical attention for primary amenorrhea. Germ cell tumors were identified in 2 patients, both with variants affecting alternative splicing of WT1 between exons 9 and 10. Two pathogenic missense WT1 variants were identified in two 46,XY individuals with Wilms' tumors; both patients were <1 year of age at the time of diagnosis. A novel WT1 variant, c.1453_1456 (p.Arg485Glyfs*14), was identified in a 46,XX patient with testicular DSD. Nephrotic proteinuria was diagnosed in all patients, including 3 who underwent renal transplantation after progressing to end-stage kidney disease. The expanding phenotypic spectrum associated with WT1 variants in XY and XX individuals confirms their pivotal role in gonadal and renal development as well as in tumorigenesis, emphasizing the clinical implications of these variants in genetic diagnosis.

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.

Disease-specific hospitalizations among 5-year survivors of Wilms tumor: A Nordic population-based cohort study

BACKGROUND

With modern therapy, over 90% of Wilms tumor patients can expect to become long-term survivors, and focus on morbidity and late effects become increasingly important. We provide a novel evaluation and insight to subsequent hospitalizations in 5-year survivors of Wilms tumor.

METHODS

As part of the Adult Life after Childhood Cancer in Scandinavia (ALiCCS) study, we identified 5-year survivors of Wilms tumor. Based on stratified random sampling, we constructed a population comparison cohort. Outcomes of interest were overall hospitalizations; hospitalizations for specific organ systems and disease-specific categories. Standardized hospitalization rate ratios (SHRR) and absolute excess risks (AER) were calculated.

RESULTS

We included 913, 5-year survivors of Wilms tumor and 152 231 population comparisons. Survivors of Wilms tumor had an increased overall risk of being hospitalized (SHRR 1.8; 95% confidence interval (CI) 1.7-2.0). The hospitalization risk was increased within all major organ systems: urinary and genital organs (SHRR 2.5; 95% CI 2.1-3.0), endocrine (SHRR 2.5; 95% CI 1.9-3.3), cardiovascular (SHRR 2.2; 95% CI 1.7-2.9), and gastrointestinal (SHRR 1.5; 95% CI 1.3-1.8). Risks for specific diseases are reported in the study.

CONCLUSIONS

Survivors of Wilms tumor had higher risks than population comparisons for a wide range of diseases, with the highest risks seen for urinary, endocrine, and cardiovascular disorders. Five to 20 years after the Wilms tumor diagnosis, 43% of survivors had been hospitalized at least once versus 29% of population comparisons. The overall AER was 2.3, which translates into 0.2 extra hospitalizations in 10 years for every Wilms tumor survivor.

Results From the WAGR Syndrome Patient Registry: Characterization of WAGR Spectrum and Recommendations for Care Management

WAGR syndrome is a rare genetic disorder characterized by Wilms tumor, Aniridia, Genitourinary anomalies, and Range of developmental delays. In addition to the classic features, patients affected by WAGR syndrome can develop obesity and kidney failure, and a wide variety of non-classical manifestations have also been described. This suggests that a broader phenotypic spectrum beyond the classic syndrome exists and here we demonstrate that spectrum using data from the WAGR Syndrome Patient Registry. In the present study, we collected information from 91 individuals enrolled in the registry to explore self-reported health issues in this patient population. A wide variety of common clinical issues not classically associated with the disorder were found, prompting the redefinition from WAGR syndrome to WAGR spectrum disorder to incorporate the phenotypic variations that occur. A comprehensive care management approach is needed to address the wide range of clinical issues and we propose a care model for patients affected by WAGR spectrum disorder. Further research is needed to solidify the breath of the phenotype and confirm the observations in this study to advance individualized patient care in this population.

The SIOP-Renal Tumour Study Group consensus statement on flank target volume delineation for highly conformal radiotherapy

For decades, radiotherapy with two opposing photon beams has been the standard technique used to cover the flank target volume in paediatric patients with renal tumours. Nowadays, many institutes are implementing advanced radiotherapy techniques that spare healthy tissue. To decrease the radiotherapy dose to healthy structures while preserving oncological efficacy, the conventional approach of flank irradiation has been adapted into a guideline for highly conformal flank target-volume delineation by paediatric radiation oncologists and representatives of the International Society of Paediatric Oncology's Renal Tumour Study Group (SIOP-RTSG) board during four live international consensus meetings. The consensus was refined by delineation exercises and videoconferences by ten collaborating paediatric radiation oncologists. The final guideline includes eight chronological steps to generate the tumour bed and clinical, internal, and planning target volumes, and it describes the optional use of surgical clips to optimise treatment planning. This guideline will be added into the radiotherapy guideline of the UMBRELLA SIOP-RTSG protocol for paediatric renal tumours to improve international consistency of highly conformal flank target-volume delineation.

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.

Long-term renal function after treatment for unilateral, nonsyndromic Wilms tumor. A report from the St. Jude Lifetime Cohort Study

BACKGROUND

The impact of specific treatment modalities on long-term renal function and blood pressure among adult survivors of Wilms tumor (WT) has not been well documented.

METHODS

Among 40 WT survivors and 35 noncancer controls, we estimated the glomerular filtration rate (eGFR) using the Chronic Kidney Disease-Epidemiology (CKD-EPI) equations with and without cystatin C, obtained 24-hour ambulatory blood pressure readings, and, among survivors only, measured ^99m Tc diethylenetriamine pentaacetic acid (DTPA) plasma clearance. Survivors were treated with unilateral nephrectomy and nonnephrotoxic chemotherapy. Twenty received whole abdomen radiation therapy (WART) [median -16.5 Gray (Gy)], and 20 received no radiation therapy. Pairwise comparisons between survivors treated with and without WART, and each group to controls were performed using two-sample t tests.

RESULTS

Twenty-six (65%) WT survivors were female, and 33 (83%) were non-Hispanic white. GFR estimated with creatinine or creatinine + cystatin C was decreased among irradiated survivors compared with controls. No irradiated or unirradiated participant had an eGFR (creatinine + cystatin C) < 60 mL/min/1.73 m² . The prevalence of hypertension was significantly increased among unirradiated (25%) and irradiated survivors (35%) compared with controls (0%). Of the 24-hour ambulatory blood pressure monitoring parameters evaluated, only mean sleep period diastolic blood pressure load of those who received WART was significantly different from that of controls.

CONCLUSIONS

Chronic kidney disease was infrequent in long-term survivors of unilateral nonsyndromic WT, whether treated with WART or no radiation. The prevalence of hypertension was increased in both groups compared with controls, emphasizing the need for ongoing monitoring of renal and cardiovascular health.

Syndromic Wilms tumor: a review of predisposing conditions, surveillance and treatment

Predisposing syndromes associated with an increased risk of Wilms tumor (WT) are responsible for 9–17% of all cases of the malignancy. Due to an earlier age at WT diagnosis and an increased incidence of bilateral and metachronous disease, management of syndromic WT warrants a distinct approach from that of non-syndromic WT. This review of English-language manuscripts about WT focuses on the most common syndromes, surveillance protocols and current treatment strategies. Highlighted syndromes include those associated with WT1, such as WAGR (Wilms-Aniridia-Genitourinary-mental Retardation), Denys-Drash syndrome (DDS), and Frasier syndrome, 11p15 defects, such as Beckwith-Wiedemann syndrome (BWS), among others. General surveillance guidelines include screening renal or abdominal ultrasound every 3–4 months until the age of 5 or 7, depending on the syndrome. Further, some of the predisposing conditions also increase the risk of other malignancies, such as gonadoblastoma and hepatoblastoma. With promising results for nephron-sparing surgery in bilateral non-syndromic WT, there are increasing reports and recommendations to pursue nephron-sparing for these patients who are at greater risk of bilateral, metachronous lesions. In addition to the loss of renal parenchyma from malignancy, many patients are at risk of developing renal insufficiency as part of their syndrome. Although there may be some increase in the complication rate, recurrence free survival seems equivalent. Some conditions require specialized approaches to adjuvant therapy, as their syndrome may make them especially susceptible to side effects.

Bilateral primary renal diffuse large B-cell lymphoma: a rare presentation of paediatric renal disease mimicking juvenile nephronophthisis

A 12-year-old boy presented with a prolonged history of headache, fatigue and hypertension. Initial investigations were consistent with presumed non-oliguric end-stage renal disease, leading to a provisional diagnosis of juvenile nephronophthisis. Subsequent imaging demonstrated bilaterally enlarged kidneys without cystic change. Mutation analysis was negative for nephronophthisis, causing diagnostic uncertainty which prompted renal biopsy. Histology revealed a primary renal diffuse large B-cell lymphoma which was highly responsive to chemotherapy, including the anti-CD20 monoclonal agent, rituximab. Renal function improved during lymphoma treatment, with residual chronic kidney disease stage 3a once chemotherapy was completed. Atypical diagnostic features should always prompt re-evaluation of a patient. In this case, the delayed malignancy diagnosis did not have an adverse effect on patient survival or morbidity. The outcome for primary renal lymphoma (PRL) has improved markedly following the introduction of rituximab.

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.

Surgery for the complex Wilms tumour

The prognosis of children with Wilms tumour has greatly improved since the introduction of adjuvant radiotherapy and chemotherapy more than 70 years ago with a current overall long-term survival approaching 90%. Before this, surgery was the only option with around 20% survival, even in low-risk categories. The focus is now on management options for those patients in specific subgroups, who continue to have lower event-free survival and who suffer from the long-term effects of treatment. These include those with anaplastic histology, bilateral Wilms, biologically high-risk tumours and those that relapse (Aldrink et al. in J Pediatr Surg 54(3):390-397, 2019). The major advances that have already been made in risk assessment and tailoring the chemotherapy/radiotherapy to achieve maximum advantage with minimum toxicity and long-term morbidity have been predicated on safe and complete resection and staging of the tumour. There are, however, still surgical challenges faced with respect to resection of 'complex' tumours; thus, surgeons need to understand their role and advance their expertise in the overall treatment of children with Wilms tumour. These include very large tumours not responding to chemotherapy, ruptured tumours, tumours with intravascular invasion into the inferior vena cava (± 10%), heart and hepatic veins (± 4%) and Wilms tumours in horseshoe kidneys (< 1%) (Kieran and Ehrlich in Urol Oncol https://doi.org/10.1016/j.urolonc.2015.05.029, 2015). This review describes surgical strategies and techniques used in these situations, gleaned from the authors' experience in the surgical management of over 300 children with Wilms tumours in our centres over the last 30 years.

Prevalence, risk factors and disease knowledge of polycystic kidney disease in Pakistan

Polycystic kidneys disease refers to cyst(s) formation in kidneys with severe consequences of end stage renal disease thus have higher mortality. It is a common genetic disease occurring either as autosomal dominant polycystic kidney (ADPKD) or autosomal recessive polycystic kidney disease (ARPKD) with prevalence rates of 1/1000 and 1/40,000 respectively. Dominant forms presenting in later (>30) while recessive in earlier ages (infancy) and affecting both sexes and almost all race. The patient experiences many renal as well as extra-renal manifestations with marked hypertension and cyst formation in other organs predominantly in liver. Due to genetic basis, positive family history is considered as major risk factor. Ultrasonography remains the main stay of diagnosis along with family history, by indicating increased renal size and architectural modifications. Initially disease remains asymptomatic, later on symptomatic treatment is suggested with surgical interventions like cyst decortications or drainage. Dialysis proved to be beneficial in end stage renal disease. However renal transplantation is the treatment of choice.

Complications Following Nephron-Sparing Surgery for Wilms Tumor

PURPOSE

Because of the increasing use of nephron-sparing surgery (NSS) in bilateral Wilms tumor, we sought to review the early postoperative complications associated with NSS.

METHODS

A retrospective review of patients who underwent NSS at our institution from 2000 to 2017 was performed. For comparison, a cohort of patients who underwent radical nephrectomy (RN) was also reviewed. Early (30-day) postoperative complications and oncologic outcomes were assessed.

RESULTS

Fifty-five patients underwent either bilateral (46) NSS or unilateral (9) NSS owing to prior resection or congenital solitary kidney. Fifty-four patients who underwent unilateral RN were also evaluated. Twenty NSS patients (36.4%) experienced 21 postoperative complications, including prolonged urine leak (9), infection (8), transient renal insufficiency (1), and intussusception (3). Seven RN patients (13.0%) experienced surgical complications, including infection (4) and intussusception (3). Average intraoperative blood loss was significantly greater in NSS as compared to RN (483.51 ± 337.92 mL and 278.15 mL ± 390.25, respectively, p < 0.001), as was the incidence of positive tumor resection margins (20 [36.4%] and 12 [22.2%], respectively, (p = 0.037).

CONCLUSIONS

In our experience, prolonged urine leak, intraoperative blood loss, and positive margins were more frequent in patients undergoing NSS as compared to RN. However, the complications were successfully managed, suggesting that an aggressive approach to NSS in patients with bilateral Wilms tumor is safe and appropriate.

LEVEL OF EVIDENCE

Level III TYPE OF STUDY: Treatment study.

Imaging of Wilms tumor: an update

Wilms tumor is the most common pediatric renal tumor, accounting for approximately 7% of all childhood cancers. Imaging plays an important role in the detection, staging, post-therapy evaluation and surveillance of Wilms tumor. Wilms tumor can be detected during surveillance of a known cancer predisposition or after a child presents with symptoms. In this manuscript we describe an evidence-based approach to the initial evaluation of Wilms tumor using current guidelines from the Children's Oncology Group (COG). We illustrate the COG staging system for pediatric renal tumors and highlight key imaging findings that are critical for surgical management. We also discuss the controversies regarding detection and significance of <5-mm pulmonary nodules at initial staging. And finally, we present some thoughts regarding surveillance of Wilms tumor, where overall survival has now approached 90%.

Solid organ transplantation after treatment for childhood cancer: a retrospective cohort analysis from the Childhood Cancer Survivor Study

BACKGROUND

Serious chronic medical conditions occur in childhood cancer survivors. We aimed to investigate incidence of and risk factors for end-organ damage resulting in registration on a waiting list for or receiving a solid organ transplantation and 5-year survival following these procedures.

METHODS

The Childhood Cancer Survivor Study (CCSS) is a retrospective cohort of individuals who survived at least 5 years after childhood cancer diagnosed at younger than 21 years of age, between Jan 1, 1970, and Dec 31, 1986, at one of 25 institutions in the USA. We linked data from CCSS participants treated in the USA diagnosed between Jan 1, 1970, and Dec 31, 1986 (without solid organ transplantation before cohort entry) to the Organ Procurement and Transplantation Network-a database of all US organ transplants. Eligible participants had been diagnosed with leukaemia, lymphoma, malignant CNS tumours, neuroblastoma, Wilms' tumours, and bone and soft tissue sarcomas. The two primary endpoints for each type of organ transplant were date of first registration of a transplant candidate on the waiting list for an organ and the date of the first transplant received. We also calculated the cumulative incidence of being placed on a waiting list or receiving a solid organ transplantation, hazard ratios (HRs) for identified risk factors, and 5-year survival following transplantation.

FINDINGS

Of 13 318 eligible survivors, 100 had 103 solid organ transplantations (50 kidney, 37 heart, nine liver, seven lung) and 67 were registered on a waiting list without receiving a transplant (21 kidney, 25 heart, 15 liver, six lung). At 35 years after cancer diagnosis, the cumulative incidence of transplantation or being on a waiting list was 0·54% (95% CI 0·40-0·67) for kidney transplantation, 0·49% (0·36-0·62) for heart, 0·19% (0·10-0·27) for liver, and 0·10% (0·04-0·16) for lung. Risk factors for kidney transplantation were unilateral nephrectomy (HR 4·2, 95% CI 2·3-7·7), ifosfamide (24·9, 7·4-83·5), total body irradiation (6·9, 2·3-21·1), and mean kidney radiation of greater than 15 Gy (>15-20 Gy, 3·6 [1·5-8·5]; >20 Gy 4·6 [1·1-19·6]); for heart transplantation, anthracycline and mean heart radiation of greater than 20 Gy (dose-dependent, both p<0·0001); for liver transplantation, dactinomycin (3·8, 1·3-11·3) and methotrexate (3·3, 1·0-10·2); for lung transplantation, carmustine (12·3, 3·1-48·9) and mean lung radiation of greater than 10 Gy (15·6, 2·6-92·7). 5-year overall survival after solid organ transplantation was 93·5% (95% CI 81·0-97·9) for kidney transplantation, 80·6% (63·6-90·3) for heart, 27·8% (4·4-59·1) for liver, and 34·3% (4·8-68·6) for lung.

INTERPRETATION

Solid organ transplantation is uncommon in ageing childhood cancer survivors. Organ-specific exposures were associated with increased solid organ transplantation incidence. Survival outcomes showed that solid organ transplantation should be considered for 5-year childhood cancer survivors with severe end-organ failure.

FUNDING

US National Institute of Health, American Lebanese Syrian Associated Charities, US Health Resources and Services Administration.

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

OBJECTIVES

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

KEY POINTS

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