Use of Sodium Thiosulfate as an Otoprotectant in Patients With Cancer Treated With Platinum Compounds: A Review of the Literature.

PURPOSE: Hearing loss occurs in 50%-70% of children treated with cisplatin. Scientific efforts have led to the recent approval of a pediatric formula of intravenous sodium thiosulfate (STS) for otoprotection by the US Food and Drug Administration, the European Medicines Agency, and the Medicines and Health Regulatory Authority in the United Kingdom. To inform stakeholders regarding the clinical utility of STS, the current review summarizes available literature on the efficacy, pharmacokinetics (PK), and safety of systemic STS to minimize cisplatin-induced hearing loss (CIHL). DESIGN: A comprehensive narrative review is presented. RESULTS: Thirty-one articles were summarized. Overall, systemic STS effectively reduces CIHL in the preclinical and controlled clinical study settings, in both adults and children with cancer. The extent of CIHL reduction depends on the timing and dosing of STS in relation to cisplatin. Both preclinical and clinical data suggest that systemic STS may affect plasma platinum levels, but studies are inconclusive. Delayed systemic administration of STS, at 6 hours after the cisplatin infusion, does not affect cisplatin-induced inhibition of tumor growth or cellular cytotoxicity in the preclinical setting, nor affect cisplatin efficacy and survival in children with localized disease in the clinical setting. CONCLUSION: Systemic administration of STS effectively reduces the development and degree of CIHL in both the preclinical and clinical settings. More studies are needed on the PK of STS and cisplatin drug combinations, the efficacy and safety of STS in patients with disseminated disease, and the ability of STS to prevent further deterioration of pre-established hearing loss.

Vorinostat, temozolomide or bevacizumab with irradiation and maintenance BEV/TMZ in pediatric high-grade glioma: A Children's Oncology Group Study.

Background: Outcomes for children with high-grade gliomas (HGG) remain poor. This multicenter phase II trial evaluated whether concurrent use of vorinostat or bevacizumab with focal radiotherapy (RT) improved 1-year event-free survival (EFS) compared to temozolomide in children with newly diagnosed HGG who received maintenance temozolomide and bevacizumab. Methods: Patients ≥ 3 and < 22 years with localized, non-brainstem HGG were randomized to receive RT (dose 54-59.4Gy) with vorinostat, temozolomide, or bevacizumab followed by 12 cycles of bevacizumab and temozolomide maintenance therapy. Results: Among 90 patients randomized, the 1-year EFS for concurrent bevacizumab, vorinostat, or temozolomide with RT was 43.8% (±8.8%), 41.4% (±9.2%), and 59.3% (±9.5%), respectively, with no significant difference among treatment arms. Three- and five-year EFS for the entire cohort was 14.8% and 13.4%, respectively, with no significant EFS difference among the chemoradiotherapy arms. IDH mutations were associated with more favorable EFS (P = .03), whereas H3.3 K27M mutations (P = .0045) and alterations in PIK3CA or PTEN (P = .025) were associated with worse outcomes. Patients with telomerase- and alternative lengthening of telomeres (ALT)-negative tumors (n = 4) had an EFS of 100%, significantly greater than those with ALT or telomerase, or both (P = .002). While there was no difference in outcomes based on TERT expression, high TERC expression was associated with inferior survival independent of the telomere maintenance mechanism (P = .0012). Conclusions: Chemoradiotherapy with vorinostat or bevacizumab is not superior to temozolomide in children with newly diagnosed HGG. Patients with telomerase- and ALT-negative tumors had higher EFS suggesting that, if reproduced, mechanism of telomere maintenance should be considered in molecular-risk stratification in future studies.

Bilateral Wilms tumor with anaplasia: A report from the Children's Oncology Group Study AREN0534.

INTRODUCTION: The purpose of this study is to examine the outcomes in children with anaplastic bilateral Wilms tumor (BWT) from study AREN0534 in order to define potential prognostic factors and areas to target in future clinical trials. METHODS: Demographic and clinical data from AREN0534 study patients with anaplasia (focal anaplasia [FA], or diffuse anaplasia [DA]) were compared. Event-free survival (EFS) and overall survival (OS) were reported using Kaplan-Meier estimation with 95% confidence bands, and differences in outcomes between FA and DA compared using log-rank tests. The impact of margin status was analyzed. RESULTS: Twenty-seven children who enrolled on AREN0534 had evidence of anaplasia (17 DA, 10 FA) in at least one kidney and were included in this analysis. Twenty-six (96%) had BWT. Nineteen percent had anaplastic histology in both kidneys (four of 17 DA, and one of 10 FA). Forty-six percent with BWT had bilateral nephron-sparing surgery (NSS); one child who went off protocol therapy, eventually required bilateral completion nephrectomies. Median follow-up for EFS and OS was 8.6 and 8.7 years from enrollment. Four- and 8-year EFS was 53% [95% confidence interval (CI): 34%-83%] for DA; 4-year EFS was 80% [95% CI: 59%-100%], and 8-year EFS 70% [95% CI: 47%-100%] for FA. Three out of 10 children with FA and eight out of 17 children with DA had events. EFS did not differ statistically by margin status (p = .79; HR = 0.88). Among the six children who died (five DA, one FA), all experienced prior relapse or progression within 18 months. CONCLUSION: Events in children with DA/FA in the setting of BWT occurred early. Caution should be taken about interpreting the impact of margin status outcomes in the context of contemporary multimodal therapy. Future targeted investigations in children with BWT and DA/FA are needed.

The RELIVE consortium for relapsed or refractory pediatric hepatoblastoma and hepatocellular carcinoma: a scoping review of the problem and a proposed solution.

Liver tumors account for approximately 2% of all pediatric malignancies. Children with advanced stages of hepatoblastoma (HB) are cured only 50-70% of the time while children with advanced hepatocellular carcinoma (HCC) have a <20% 5-year overall survival. This scoping review was performed to highlight the paucity of rigorous, reliable data guiding the management of relapsed pediatric HB or HCC. When these patients are enrolled on prospective trials, the trials are often histology-agnostic, exclude patients less than a year of age, lack a liquid formulary of the drug under study, exclude recipients of a solid organ transplant, and enroll only 1-2 patients limiting the ability to deduce efficacious regimens for current use or future study. We highlight the creation of a global pediatric consortium intended to source retrospective relapse data from over 100 institutions spanning 4 continents. The data collected from this effort will inform future relapse trials.

Treatment and outcomes of clear cell sarcoma of the kidney: A report from the Children's Oncology Group studies AREN0321 and AREN03B2.

BACKGROUND: On the fifth National Wilms Tumor Study, treatment for clear cell sarcoma of the kidney (CCSK) included combined vincristine, doxorubicin, cyclophosphamide, and etoposide (regimen I) plus radiation therapy (RT), yielding 5-year event-free survival (EFS) rates of 100%, 88%, 73%, and 29% for patients who had with stage I, II, III, and IV disease, respectively. In the Children's Oncology Group study AREN0321 of risk-adapted therapy, RT was omitted for stage I disease if lymph nodes were sampled, and carboplatin was added for stage IV disease (regimen UH-1). Patients who had stage II/III disease received regimen I with RT. METHODS: Four-year EFS was analyzed for patients enrolled on AREN0321 and on those enrolled on AREN03B2 who received AREN0321 stage-appropriate chemotherapy. RESULTS: Eighty-two patients with CCSK enrolled on AREN0321, 50 enrolled on AREN03B2 only. The 4-year EFS rate was 82.7% (95% confidence interval [CI], 74.8%-91.4%) for AREN0321 and 89.6% (95% CI, 81.3%-98.7%) for AREN03B2 only (p = .28). When combining studies, the 4-year EFS rates for patients who had stage I (n = 10), II (n = 47), III (n = 65), and IV (n = 10) disease were 90% (95% CI, 73.2%-100.0%), 93.4% (95% CI, 86.4%-100.0%), 82.8% (95% CI, 74.1%-92.6%), and 58.3% (95% CI, 34%-100.0%), respectively. There were no local recurrences among seven patients with stage I disease who were treated without RT. One stage I recurrence occurred in the brain, which was the most common site of relapse overall. Among patients with local stage III tumors, neither initial procedure type, margin status, nor lymph node involvement were prognostic. CONCLUSIONS: Patients with stage I CCSK had excellent outcomes without local recurrences when treated without RT. Patients with stage IV disease appeared to benefit from a carboplatin-containing regimen, although their outcomes remained unsatisfactory. Further research is needed to improve outcomes for patients with advanced-stage disease (ClinicalTrials.gov identifiers NCT00335556 and NCT00898365).

Race and Ethnic Group Enrollment and Outcomes for Wilms Tumor: Analysis of the Current Era Children's Oncology Group Study, AREN03B2.

BACKGROUND: To review race and ethnic group enrollment and outcomes for Wilms tumor (WT) across all 4 risk-assigned therapeutic trials from the current era Children's Oncology Group Renal Tumor Biology and Risk Stratification Protocol, AREN03B2. STUDY DESIGN: For patients with WT enrolled in AREN03B2 (2006 to 2019), disease and biologic features, therapeutic study-specific enrollment, and event-free (EFS) and overall (OS) 4-year survival were compared between institutionally reported race and ethnic groups. RESULTS: Among 5,146 patients with WT, no statistically significant differences were detected between race and ethnic groups regarding subsequent risk-assigned therapeutic study enrollment, disease stage, histology, biologic factors, or overall EFS or OS, except the following variables: Black children were older and had larger tumors at enrollment, whereas Hispanic children had lower rates of diffuse anaplasia WT and loss of heterozygosity at 1p. The only significant difference in EFS or OS between race and ethnic groups was observed among the few children treated for diffuse anaplasia WT with regimen UH-1 and -2 on high-risk protocol, AREN0321. On this therapeutic arm only, Black children showed worse EFS (hazard ratio = 3.18) and OS (hazard ratio = 3.42). However, this finding was not replicated for patients treated with regimen UH-1 and -2 under AREN03B2 but not on AREN0321. CONCLUSIONS: Race and ethnic group enrollment appeared constant across AREN03B2 risk-assigned therapeutic trials. EFS and OS on these therapeutic trials when analyzed together were comparable regarding race and ethnicity. Black children may have experienced worse stage-specific survival when treated with regimen UH-1 and -2 on AREN0321, but this survival gap was not confirmed when analyzing additional high-risk AREN03B2 patients.

Cellular origin and molecular mechanisms of lung metastases in patients with aggressive hepatoblastoma.

BACKGROUND AND AIMS: Lung metastases are the most threatening signs for patients with aggressive hepatoblastoma (HBL). Despite intensive studies, the cellular origin and molecular mechanisms of lung metastases in patients with aggressive HBL are not known. The aims of these studies were to identify metastasis-initiating cells in primary liver tumors and to determine if these cells are secreted in the blood, reach the lung, and form lung metastases. APPROACH: We have examined mechanisms of activation of key oncogenes in primary liver tumors and lung metastases and the role of these mechanisms in the appearance of metastasis-initiating cells in patients with aggressive HBL by RNA-Seq, immunostaining, chromatin immunoprecipitation, Real-Time Quantitative Reverse Transcription PCR and western blot approaches. Using a protocol that mimics the exit of metastasis-initiating cells from tumors, we generated 16 cell lines from liver tumors and 2 lines from lung metastases of patients with HBL. RESULTS: We found that primary HBL liver tumors have a dramatic elevation of neuron-like cells and cancer-associated fibroblasts and that these cells are released into the bloodstream of patients with HBL and found in lung metastases. In the primary liver tumors, the ph-S675-ß-catenin pathway activates the expression of markers of cancer-associated fibroblasts; while the ZBTB3-SRCAP pathway activates the expression of markers of neurons via cancer-enhancing genomic regions/aggressive liver cancer domains leading to a dramatic increase of cancer-associated fibroblasts and neuron-like cells. Studies of generated metastasis-initiating cells showed that these cells proliferate rapidly, engage in intense cell-cell interactions, and form tumor clusters. The inhibition of ß-catenin in HBL/lung metastases-released cells suppresses the formation of tumor clusters. CONCLUSIONS: The inhibition of the ß-catenin-cancer-enhancing genomic regions/aggressive liver cancer domains axis could be considered as a therapeutic approach to treat/prevent lung metastases in patients with HBL.

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.

Prognostic impact of lymph node involvement and loss of heterozygosity of 1p or 16q in stage III favorable histology Wilms tumor: A report from Children's Oncology Group Studies AREN03B2 and AREN0532.

INTRODUCTION: The prognostic impact of positive lymph nodes (LN+) and/or singular loss of heterozygosity (LOH) of 1p or 16q were assessed in children with stage III favorable histology Wilms tumor (FHWT) enrolled on AREN0532 or AREN03B2 alone. PATIENTS AND METHODS: A total of 635 stage III FHWT vincristine/dactinomycin/doxorubicin (DD4A)-treated patients met inclusion criteria. Event-free survival (EFS) and overall survival are reported overall and by LN sampling, LN status, LOH 1p, LOH 16q, and a combination of LN status and singular LOH. Patients with unknown or positive combined LOH of 1p and 16q status and AREN03B2-only patients with unknown outcomes or treatment other than DD4A were excluded. RESULTS: EFS did not differ by study, supporting pooling. Lack of LN sampling (hazard ratio [HR], 2.12; p = .0037), LN positivity (HR, 2.78; p = .0002), LOH 1p (HR, 2.18; p = .0067), and LOH 16q (HR, 1.72; p = .042) were associated with worse EFS. Compared with patients with both LN- and LOH-, those with negative nodes but positive LOH 1p or 16q and those with LN+ but LOH- for 1p or 16q had significantly worse EFS (HR, 3.05 and 3.57, respectively). Patients positive for both LN and LOH had the worst EFS (HR, 6.33; overall group factor, p < .0001). CONCLUSION: Findings confirm LN+ status as an adverse prognostic factor amplified by presence of singular LOH 1p or 16q, supporting study of intensified therapy for patients with LN+ in combination with singular LOH in a prospective clinical trial.

EZH2 is a key component of hepatoblastoma tumor cell growth.

BACKGROUND: Enhancer of zeste homolog 2 (EZH2) catalyzes the trimethylation of histone H3 at lysine 27 via the polycomb recessive complex 2 (PRC2) and plays a time-specific role in normal fetal liver development. EZH2 is overexpressed in hepatoblastoma (HB), an embryonal tumor. EZH2 can also promote tumorigenesis via a noncanonical, PRC2-independent mechanism via proto-oncogenic, direct protein interaction, including ß-catenin. We hypothesize that the pathological activation of EZH2 contributes to HB propagation in a PRC2-independent manner. METHODS AND RESULTS: We demonstrate that EZH2 promotes proliferation in HB tumor-derived cell lines through interaction with ß-catenin. Although aberrant EZH2 expression occurs, we determine that both canonical and noncanonical EZH2 signaling occurs based on specific gene-expression patterns and interaction with SUZ12, a PRC2 component, and ß-catenin. Silencing and inhibition of EZH2 reduce primary HB cell proliferation. CONCLUSIONS: EZH2 overexpression promotes HB cell proliferation, with both canonical and noncanonical function detected. However, because EZH2 directly interacts with ß-catenin in human tumors and EZH2 overexpression is not equal to SUZ12, it seems that a noncanonical mechanism is contributing to HB pathogenesis. Further mechanistic studies are necessary to elucidate potential pathogenic downstream mechanisms and translational potential of EZH2 inhibitors for the treatment of HB.

Treatment of children with favorable histology Wilms tumor with extrapulmonary metastases: A report from the COG studies AREN0533 and AREN03B2 and NWTSG study NWTS-5.

BACKGROUND: Patients with stage IV favorable histology Wilms tumor (FHWT) with extrapulmonary metastases (EPM) constitute a small subset of patients with FHWT. Because of their rarity and heterogeneity, optimal FHWT treatment is not well understood. Children's Oncology Group protocol AREN0533 assigned patients with FHWT and EPM to intensified chemotherapy, regimen M, after initial DD-4A chemotherapy. To improve understanding of prognostic factors and best therapies, experiences of patients with EPM on AREN0533, as well as on protocols AREN03B2 and NWTS-5, were reviewed. METHODS: Combined outcomes for patients with EPM from NWTS-5, AREN0533, and AREN03B2 were determined. Those treated on AREN0533 were compared with those treated on NWTS-5. Prognostic factors were explored in the pooled cohort. RESULTS: Forty-seven patients with FHWT with EPM enrolled on AREN0533, 37 enrolled on NWTS-5, and 64 were followed only on AREN03B2. The pooled cohort of all 148 patients demonstrated a 4-year event-free survival (EFS) of 77.3% (95% CI, 70.8-84.4) and 4-year overall survival of 88.9% (95% CI, 83.9-94.2). Four-year EFS of patients with EPM treated on AREN0533 was 76.0% (95% CI, 64.6-89.4) vs 64.9% (95% CI, 51.7-82.2) on NWTS-5; hazard ratio, 0.64, p = .26; no difference in overall survival was observed. Increasing linear age and slow incomplete lung response were associated with worse EFS in a pooled cohort. CONCLUSIONS: Outcomes for patients with EPM are among the lowest for children with FHWT. Further trials with standardized surgical and radiation treatment to metastatic sites, and prospectively collected biologic and treatment details are needed. CLINICAL TRIAL REGISTRATION: Clinical Trials.gov identifiers: NCT00379340, NCT00898365, and NCT00002611.

BRAF Exon 15 Mutations in the Evaluation of Well-Differentiated Epithelial Nephroblastic Neoplasms in Children: A Report From the Children's Oncology Group Study AREN03B2.

CONTEXT.­: The distinction between well-differentiated epithelial favorable-histology Wilms tumor (EFHWT) and metanephric adenoma (MA) in children has historically been determined by the required absence of both a fibrous pseudocapsule and mitotic activity in MA. More recently these features have been allowed in adult MA. Mutations in exon 15 of the BRAF gene are reported in up to 88% of MAs but have not been reported in EFHWTs. OBJECTIVE.­: To clarify the pathologic and molecular features used to distinguish between pediatric MA and EFHWT. DESIGN.­: Stage I epithelial tumors classified as EFHWT on central review (36 patients) were identified from the Children's Oncology Group AREN03B2 study. Thirteen tumors had morphologic features overlapping those of MA and 23 lacked such features; 35 of 36 had tissue available for sequencing of BRAF. RESULTS.­: Patients with EFHWTs with MA features (13) were older (mean, 8.4 versus 1.9 years; P < .001), had smaller tumor diameters (mean, 6.0 versus 9.7 cm; P < .001), and had fewer mitoses (mean, 1 versus 48 mitoses per 10 high-power fields; P < .001) than patients with EFHWT lacking MA features (23). All EFHWTs with MA features contained at least a partial fibrous pseudocapsule; 7 of 12 (58%) had BRAF exon 15 mutation. No BRAF exon 15 mutations were identified in 23 EFHWTs lacking MA features. None of the 13 EFHWT patients with MA features have experienced relapse (median follow-up 5.9 years). CONCLUSIONS.­: Pediatric epithelial neoplasms with features of MA that show partial encapsulation and/or modest mitotic activity may be classified as MAs. Although BRAF mutation supports the diagnosis of MA, it is not required for the diagnosis.

Genetic and epigenetic features of bilateral Wilms tumor predisposition in patients from the Children's Oncology Group AREN18B5-Q.

Developing synchronous bilateral Wilms tumor suggests an underlying (epi)genetic predisposition. Here, we evaluate this predisposition in 68 patients using whole exome or genome sequencing (n = 85 tumors from 61 patients with matched germline blood DNA), RNA-seq (n = 99 tumors), and DNA methylation analysis (n = 61 peripheral blood, n = 29 non-diseased kidney, n = 99 tumors). We determine the predominant events for bilateral Wilms tumor predisposition: 1)pre-zygotic germline genetic variants readily detectable in blood DNA [WT1 (14.8%), NYNRIN (6.6%), TRIM28 (5%), and BRCA-related genes (5%)] or 2)post-zygotic epigenetic hypermethylation at 11p15.5 H19/ICR1 that may require analysis of multiple tissue types for diagnosis. Of 99 total tumor specimens, 16 (16.1%) have 11p15.5 normal retention of imprinting, 25 (25.2%) have 11p15.5 copy neutral loss of heterozygosity, and 58 (58.6%) have 11p15.5 H19/ICR1 epigenetic hypermethylation (loss of imprinting). Here, we ascertain the epigenetic and genetic modes of bilateral Wilms tumor predisposition.

Retreatment with Cisplatin May Provide a Survival Advantage for Children with Relapsed/Refractory Hepatoblastoma: An Institutional Experience.

BACKGROUND: Hepatoblastoma (HB) is the most common liver malignancy in children. There is no standard of care for management of relapsed/refractory HB (rrHB) and reports in the literature are limited. OBJECTIVE: To describe presenting features, biology, treatment strategies, and outcomes for pediatric patients with relapsed/refractory hepatoblastoma. METHODS: An IRB-approved retrospective institutional review of patients with rrHB who presented for consultation and/or care from 2000-2019. Clinical, radiographic, and histologic data were collected from all patients. RESULTS: Thirty subjects were identified with a median age of 19.5 months (range 3-169 months) at initial diagnosis and 32.5 months (range 12-194 months) at time of first relapse. 63% of subjects were male, 70% Caucasian, and 13% were born premature. Three subjects had a known cancer predisposition syndrome. Eight patients had refractory disease while 22 patients had relapsed disease. Average time from initial diagnosis to relapse or progression was 12.5 months. Average alpha-fetoprotein (AFP) at initial diagnosis was 601,203 ng/mL (range 121-2,287,251 ng/mL). Average AFP at relapse was 12,261 ng/mL (range 2.8-201,000 ng/mL). For patients with tumor sequencing (n = 17), the most common mutations were in CTNNB1 (13) and NRF2 (4). First relapse sites were lungs (n = 12), liver (n = 11) and both (n = 6). More than one relapse/progression occurred in 47% of subjects; 6 had ≥3 relapses. Pathology in patients with multiply relapsed disease was less differentiated including descriptions of small cell undifferentiated (n = 3), pleomorphic (n = 1), transitional liver cell tumor (n = 2) and HB with carcinoma features (n = 1). All subjects underwent surgical resection of site of relapsed disease with 7 subjects requiring liver transplantation. Overall survival was 50%. Survival was associated with use of cisplatin at relapse (78.6% with vs. 25% without, p = 0.012). The most common late effect was ototoxicity with at least mild sensorineural hearing loss found in 80% of subjects; 54% required hearing aids. CONCLUSIONS: Retreatment with cisplatin at the time of relapse may provide an advantage for some patients with hepatoblastoma. Multiply relapsed disease was not uncommon and not associated with a worse prognosis. Careful attention should be paid to cumulative therapy-induced toxicity while concurrently aiming to improve cure.

Children's Oncology Group's 2023 blueprint for research: Liver tumors.

Liver tumors account for approximately 1%-2% of all pediatric malignancies, with the two most common tumors being hepatoblastoma (HB) and hepatocellular carcinoma (HCC). Previous Children's Oncology Group studies have meaningfully contributed to the current understanding of disease pathophysiology and treatment, laying groundwork for the ongoing prospective international study of both HB and HCC. Future work is focused on elucidating the biologic underpinnings of disease to support an evolution in risk categorization, advancements in the multidimensional care required to treat these patients, and the discovery of novel therapies.

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.

Severe Hepatopathy in National Wilms Tumor Studies 3-5: Prevalence, Clinical Features, and Outcomes After Reintroduction of Chemotherapy.

PURPOSE: The safety of reintroducing chemotherapy in the pediatric renal tumor setting after severe hepatopathy (SH), including sinusoidal obstruction syndrome (SOS), is uncertain. We describe the incidence, severity, outcomes, and impact on subsequent treatment for patients with SH from National Wilms Tumor Study (NWTS) protocols 3-5. PATIENTS AND METHODS: Archived charts for patients enrolled on NWTS 3-5 who met study inclusion criteria for SH by using established hepatopathy grading scales and clinical criteria were reviewed for demographics, tumor characteristics, radio- and chemotherapy details, SH-related dose modifications, and oncologic outcomes. Genomic analysis for candidate polymorphisms associated with SH was performed in 14 patients. RESULTS: Seventy-one of 8,862 patients (0.8%) met study inclusion criteria. The median time from therapy initiation to SH was 51 days (range, 2-293 days). Sixty percent received radiotherapy, and 56% had right-sided tumors. Grade 1-4 thrombocytopenia was noted in 70% at initial occurrence of SH (median 22,000/microliter). Among 69 of 71 children with SH occurring before the end of therapy (EOT) and post-SH treatment information available, chemotherapy was delayed posthepatopathy for 65% (69% of these at a reduced dose), continued without delay for 20% (57% of these at reduced dose), and stopped completely for 15% (4 of 10 of whom died of SH). Overall, 42% of patients with dose reductions achieved full dose by EOT. The five-year post-SH event-free survival for patients who continued therapy was 89% (95% CI, 81 to 98), with no significant differences by whether delay or dose reduction occurred. We identified no SH-associated pharmacogenomic polymorphism. CONCLUSION: The incidence of SH on NWTS 3-5 was low; many had associated severe thrombocytopenia. Careful reintroduction of chemotherapy appeared to be feasible for the majority of patients who developed severe chemotherapy- and/or radiotherapy-induced liver toxicity.

Quality of Life Outcomes for Patients Who Underwent Conventional Resection and Liver Transplantation for Locally Advanced Hepatoblastoma.

Hepatoblastoma is the most common malignant liver tumor of childhood, with liver transplant and extended resection used as surgical treatments for locally advanced tumors. Although each approach has well-described post-operative complications, quality-of-life outcomes have not been described following the two interventions. Long-term pediatric survivors of hepatoblastoma who underwent conventional liver resection or liver transplantation at a single institution from January 2000-December 2013 were recruited to complete quality-of-life surveys. Survey responses for the Pediatric Quality of Life Generic Core 4.0 (PedsQL, n = 30 patient and n = 31 parent surveys) and Pediatric Quality of Life Cancer Module 3.0 (PedsQL-Cancer, n = 29 patient and n = 31 parent surveys) were collected from patients and parents. The mean total patient-reported PedsQL score was 73.7, and the parent-reported score was 73.9. There were no significant differences in scores on the PedsQL between patients who underwent resection compared to those who underwent transplantation (p > 0.05 for all comparisons). On the PedsQL-Cancer module, procedural anxiety scores were significantly lower for patients who underwent resection as compared to transplant (M = 33.47 points less, CI [-60.41, -6.53], p-value 0.017). This cross-sectional study demonstrates that quality of life outcomes are overall similar among patients receiving transplants and resections. Patients who received a resection reported worse procedural anxiety.

The Genetic and Epigenetic Features of Bilateral Wilms Tumor Predisposition: A Report from the Children's Oncology Group AREN18B5-Q Study.

This study comprehensively evaluated the landscape of genetic and epigenetic events that predispose to synchronous bilateral Wilms tumor (BWT). We performed whole exome or whole genome sequencing, total-strand RNA-seq, and DNA methylation analysis using germline and/or tumor samples from 68 patients with BWT from St. Jude Children's Research Hospital and the Children's Oncology Group. We found that 25/61 (41%) of patients evaluated harbored pathogenic or likely pathogenic germline variants, with WT1 (14.8%), NYNRIN (6.6%), TRIM28 (5%) and the BRCA-related genes (5%) BRCA1, BRCA2, and PALB2 being most common. Germline WT1 variants were strongly associated with somatic paternal uniparental disomy encompassing the 11p15.5 and 11p13/WT1 loci and subsequent acquired pathogenic CTNNB1 variants. Somatic coding variants or genome-wide copy number alterations were almost never shared between paired synchronous BWT, suggesting that the acquisition of independent somatic variants leads to tumor formation in the context of germline or early embryonic, post-zygotic initiating events. In contrast, 11p15.5 status (loss of heterozygosity, loss or retention of imprinting) was shared among paired synchronous BWT in all but one case. The predominant molecular events for BWT predisposition include pathogenic germline variants or post-zygotic epigenetic hypermethylation at the 11p15.5 H19/ICR1 locus (loss of imprinting). This study demonstrates that post-zygotic somatic mosaicism for 11p15.5 hypermethylation/loss of imprinting is the single most common initiating molecular event predisposing to BWT. Evidence of somatic mosaicism for 11p15.5 loss of imprinting was detected in leukocytes of a cohort of BWT patients and long-term survivors, but not in unilateral Wilms tumor patients and long-term survivors or controls, further supporting the hypothesis that post-zygotic 11p15.5 alterations occurred in the mesoderm of patients who go on to develop BWT. Due to the preponderance of BWT patients with demonstrable germline or early embryonic tumor predisposition, BWT exhibits a unique biology when compared to unilateral Wilms tumor and therefore warrants continued refinement of its own treatment-relevant biomarkers which in turn may inform directed treatment strategies in the future.