Optimal duration of preoperative therapy in unilateral and nonmetastatic Wilms' tumor in children older than 6 months: results of the Ninth International Society of Pediatric Oncology Wilms' Tumor Trial and Study

Omission of adjuvant chemotherapy in patients with completely necrotic Wilms tumor stage I and radiotherapy in stage III: The 30-year SIOP-RTSG experience

BACKGROUND

Completely necrotic Wilms tumor (CN-WT) following preoperative chemotherapy has been regarded as low-risk WT since the International Society of Paediatric Oncology (SIOP) 93-01 study, and patients have been treated with reduced postoperative therapy. The aim of the study was to evaluate whether the omission of adjuvant chemotherapy in patients with localized CN-WT stage I and radiotherapy in stage III was safe.

PATIENTS AND METHODS

The retrospective observational study of outcomes of patients diagnosed with localized CN-WT on central pathology review and treated according to the SIOP 93-01 and SIOP-WT-2001 protocols (1993-2022).

RESULTS

There were 125 patients with localized CN-WT: 90 with stage I, 10 with stage II, and 25 with stage III. Sixty-two of 125 (49.6%) patients had a discrepant diagnosis and/or staging between the institutional pathologist and central pathology review. In the group of 90 patients with stage I, postoperative chemotherapy was not given to 41 (46%) patients, whereas 49 patients received postoperative chemotherapy-in the latter group, two patients relapsed, and one of them died. One stage I and one stage II patient developed chemotherapy-induced toxicity and died. Nineteen of 25 patients with stage III received no flank radiotherapy. No stage III patient relapsed or died. The overall 5-year event-free survival (EFS) estimate for the entire cohort (stages I-III) was 96.8% [95% confidence interval, CI: 93.6%-99.6%] and the overall survival (OS) was 97.6% [95% CI: 95.0-100%]. The EFS and OS were 97% and 98%, respectively, for stage I, and 100% for stage III.

CONCLUSION

Omission of postoperative chemotherapy for patients with CN-WT stage I, and radiotherapy for stage III is safe. Rapid central pathology review is required to assign appropriate treatment and avoid treatment-related side effects.

Bilateral Wilms Tumor in CLOVES Syndrome

Wilms tumor is the most common pediatric renal mass and occurs in up to 10% of predisposition syndromes. One such syndrome is CLOVES syndrome, an extremely rare disorder within the umbrella of PIK3CA-related overgrowth spectrum disorders. This case presents the management of a bilateral Wilms tumor in a patient with CLOVES syndrome and highlights the many intricacies in caring for complex oncology patients. Particularly highlighted in this case is the delicate line in balancing the risks of treatment-related morbidity against the risks of recurrence in predisposed patients, while still abiding by established treatment guidelines.

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.

WAGR, Sex Reversal, Bilateral Gonadoblastomas, and Intralobar Nephrogenic Rests: Uncertainties of Pre-Biopsy Chemotherapy in a High Risk Syndrome for Nephroblastoma

Background: WT1 deletions are associated with nephroblastomas, WT mutations are associated with 46, XY sex reversal. It is unclear why only a few WT1 deletions are associated with sex reversal. Case report. This 46, XY female had a 15.2 MB interstitial deletion of 11p14.1p11.2, which included WT1 and FSHB. No pathogenic abnormalities were identified in 156 other genes associated with disorders of sexual development. Bilateral gonadoblastomas were incidentally diagnosed at 17 months of age at the time of prophylactic gonadectomies. She was treated without biopsy for bilateral nephroblastomas radiologically identified at 18 months of age. Bilateral partial nephrectomies contained treated intralobular nephrogenic rests. Conclusion: It is unclear why WT1 deletions are less associated with 46, XY sex reversal than WT1 mutations. Treating suspected nephroblastomas without biopsy, even in patients with syndromes associated with bilateral nephroblastomas, may still lead to diagnostic and therapeutic uncertainties.

Similarities and controversies in imaging of pediatric renal tumors: A SIOP-RTSG and COG collaboration

Malignant renal tumors are rare in children, and Wilms tumors (WTs) are the most common subtype. Imaging plays an essential role in the diagnosis, staging, and follow-up of these patients. Initial workup for staging is mainly performed by cross-sectional imaging modalities such as computed tomography (CT) and magnetic resonance imaging (MRI). Imaging approach within the two core international groups, the Children's Oncology Group (COG, North America) and the International Society of Pediatric Oncology - Renal Tumor Study Group (SIOP-RTSG, Europe), differs. Whereas abdominal ultrasound (US) is used for the initial diagnosis of a suspected pediatric renal tumor globally, COG protocols support the use of CT or MRI for locoregional staging, contrary to the preference for MRI over CT for abdominopelvic evaluation within the SIOP-RTSG. The purpose of this manuscript is to summarize current imaging approaches, highlighting differences and similarities within these core international groups, while focusing on future innovative efforts and collaboration within the HARMONICA initiative.

A higher tumor volume and undernutrition at diagnosis adversely affect the survival of children with Wilms tumor: A study of 200 patients

BACKGROUND

Distinct prognostic factors for Wilms tumor (WT) in low- and middle-income countries need identification.

METHODS

Retrospective study of patients with WT managed by the International Society of Pediatric Oncology (SIOP) approach for over 11 years (2005-2016) at a single center in Chandigarh, India.

RESULTS

The study included 200 patients (median age: 33.5 months). The tumor stage (SIOP) distribution included stage I (30%), II (36%), III (14%), IV (17%), and V (3%). The histology-risk groups were low (8%), intermediate (84%), and high risk (9%). At diagnosis, 68 out of 190 (36%) patients were underweight. The median tumor volume at diagnosis was 481 ml (interquartile ratio [IQR]: 306.9, 686.8, n = 146). Following neoadjuvant chemotherapy, it reduced to 110 ml (IQR: 151.2, 222, n = 77). Treatment was abandoned in 20.5% of the patients. Treatment-related mortality occurred in 13 of 179 (7.2%) patients. Relapse occurred in 26 of 158 (16.5%) patients. The 3-year overall survival (OS) and event-free survival (EFS) of patients who completed therapy were 78.3 and 72%, respectively. The stage (p = .013) and histology (p = .023) influenced OS. A lower OS in stage II (75.4%) versus stage III disease (83.7%) suggested understaging. Patients with a higher tumor volume at diagnosis (p = .005; odds ratio [OR]: 0.99; 95% confidence interval [CI]: 0.99-1.00) or a lower weight-for-age z-score (p = .002; OR: 1.68; 95% CI: 1.21-2.33) had an increased risk of death or relapse.

CONCLUSIONS

The 3-year OS and EFS of children who completed therapy were 78.3 and 72%, respectively. A higher tumor volume and lower weight-for-age z-score at diagnosis were identified as distinct adverse prognostic factors. A likely suboptimal lymph node assessment (intraoperative and histopathology) contributed to the understaging of stage III to II disease and reduced survival.

Incidence patterns of childhood non-Wilms renal tumors: Comparing data of the Nationwide Registry of Childhood Hematological Malignancies and Solid Tumors (NARECHEM-ST), Greece, and the Surveillance, Epidemiology, and End Results Program (SEER), USA

BACKGROUND

We used, for the first time, data registered in the Nationwide Registry for Childhood Hematological Malignancies and Solid Tumors (NARECHEM-ST)-Greece to estimate incidence/time trends of the rare childhood (0-14 years) non-Wilms tumors (non-WT), and compared the results of malignant non-WT to those from the Surveillance, Epidemiology, and End Results Program (SEER)-USA.

METHODS

Fifty-five cases (n = 33 malignant-only) were extracted from NARECHEM-ST (2001-2020) and 332 malignant cases from SEER (1990-2017). To allow between-country comparisons, age-standardized incidence rates (AIR) of malignant-only non-WT were calculated, and temporal trends were evaluated using Poisson and joinpoint regressions.

RESULTS

In NARECHEM-ST, malignant and non-malignant non-WT accounted for 22.6% of all renal tumors. Among malignant tumors, the AIR was 1.0/106 children in Greece, similar to that calculated for SEER, USA (AIR=0.9/106). The proportion of infant malignant and non-malignant non-WT was 27% (20% before 6 months) in NARECHEM-ST. Most common non-WT in Greece were congenital mesoblastic nephromas (CMN) diagnosed mainly in infancy (CIR=7.2/106). The proportion of infant malignant non-WT was 20% in SEER (AIRinfancy=2.5/106), mainly attributed to rhabdoid tumors (CIR=1.6/106). The male-to-female (M:F) ratio of malignant non-WT was 0.9 in NARECHEM-ST vs. 1.2 in SEER, whereas boys outnumbered girls with clear cell sarcoma in NARECHEM-ST (M:F=4.0). Lastly, significantly increasing trends in incidence rates were noted in NARECHEM-ST [+ 6.8%, 95% confidence intervals (CI): 0.5, 13.3] and in SEER (+7.3%, 95%CI: 5.6, 9.0).

CONCLUSIONS

Observed incidence, time trends and sociodemographic variations of non-WT may reflect differential registration practices and healthcare delivery patterns including differences regarding surveillance, coding and treatment practices.

Fasting Intervention for Children With Unilateral Renal Tumors to Reduce Toxicity

Childhood renal tumors account for around 6% of all childhood cancers and 90% of these cases are Wilms tumor. In Europe, the SIOP-RTSG approach is considered standard of care and has resulted in five-year survival rates of over 90%. Efforts to decrease toxicity are now being pursued. Short-term fasting (STF), a short but strong reduction in calorie-intake, is associated with improved fitness, enhanced coping with acute physical stress and a lower risk of age-associated diseases. STF temporarily reduces growth to boost resilience, maintenance, and defense-mechanisms, by which toxic side-effects of (oxidative) damage and inflammation are largely prevented. Renal surgery for Wilms tumor carries a risk of acute kidney injury (AKI) and pediatric patients that had an episode of AKI are at increased risk for developing chronic renal disease. STF could mitigate surgery-induced stress and could further improve outcomes. We aim to investigate the effect of STF on renal function recovery after renal tumor surgery by conducting a single-center, prospective, randomized, non-blinded, intervention study. Children diagnosed with a unilateral renal tumor and opting for curative treatment are eligible for inclusion. The main study objective is to investigate the potential decrease in occurrence of AKI due to STF. Secondary objectives include renal function recovery, child's wellbeing, physical functioning, and feasibility of and adherence to STF in children with cancer.

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.

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.

Assessment of BCOR Internal Tandem Duplications in Pediatric Cancers by Targeted RNA Sequencing

Alterations in the BCOR gene, including internal tandem duplications (ITDs) of exon 15 have emerged as important oncogenic changes that define several diagnostic entities. In pediatric cancers, BCOR ITDs have recurrently been described in clear cell sarcoma of kidney (CCSK), primitive myxoid mesenchymal tumor of infancy (PMMTI), and central nervous system high-grade neuroepithelial tumor with BCOR ITD in exon 15 (HGNET-BCOR ITDex15). In adults, BCOR ITDs are also reported in endometrial and other sarcomas. The utility of multiplex targeted RNA sequencing for the identification of BCOR ITD in pediatric cancers was investigated. All available archival cases of CCSK, PMMTI, and HGNET-BCOR ITDex15 were collected. Each case underwent anchored multiplex PCR library preparation with a custom-designed panel, with BCOR targeted for both fusions and ITDs. BCOR ITD was detected in all cases across three histologic subtypes using the RNA panel, with no other fusions identified in any of the cases. All BCOR ITDs occurred in the final exon, within 16 codons from the stop sequence. Multiplex targeted RNA sequencing from formalin-fixed, paraffin-embedded tissue is successful at identifying BCOR internal tandem duplications. This analysis supports the use of anchored multiplex PCR targeted RNA next-generation sequencing panels for identification of BCOR ITDs in pediatric tumors. The use of post-analytic algorithms to improve the detection of BCOR ITD using DNA panels was also explored.

Wilms tumor

The objectives for the treatment of Wilms tumor in both the Children's Oncology Group (COG) and the International Society of Paediatric Oncology (SIOP) have focused on improving cure rates and minimizing toxicity by limiting the use of radiation and doxorubicin. Although the timing of surgery is different in COG (upfront surgery) and SIOP (upfront chemotherapy with delayed surgery), both are effective strategies and have the same survival. Fewer patients are treated with radiotherapy in the SIOP trials but with higher doses. The prognostic significance of biological markers such as 1q gain and clinical outcomes with novel radiation techniques such as intensity modulated radiation therapy will be determined in upcoming clinical trials. A closer collaboration between COG and SIOP could help promote research and improve the clinical outcomes of children with Wilms tumor.

Outcome of Stage IV Completely Necrotic Wilms Tumour and Local Stage III Treated According to the SIOP 2001 Protocol

Simple Summary

Around 15–20% of all Wilms tumour (WT) patients present with metastatic disease. Approximately 10% of these patients achieve complete necrosis after preoperative chemotherapy, which is associated with a favourable prognosis. The aim of this observational study is to describe the outcome of metastatic patients with completely necrotic (low-risk histology), local stage III WT treated according to the SIOP 2001 protocol, whether or not postoperative radiotherapy was applied.

Abstract

Objective: Wilms tumour (WT) patients with a localised completely necrotic nephroblastoma after preoperative chemotherapy are a favourable outcome group. Since the introduction of the SIOP 2001 protocol, the SIOP– Renal Tumour Study Group (SIOP–RTSG) has omitted radiotherapy for such patients with low-risk, local stage III in an attempt to reduce treatment burden. However, for metastatic patients with local stage III, completely necrotic WT, the recommendations led to ambiguous use. The purpose of this descriptive study is to demonstrate the outcomes of patients with metastatic, completely necrotic and local stage III WT in relation to the application of radiotherapy or not. Methods and materials: all metastatic patients with local stage III, completely necrotic WT after 6 weeks of preoperative chemotherapy who were registered in the SIOP 2001 study were included in this analysis. The pattern of recurrence according to the usage of radiation treatment and 5 year event-free survival (EFS) and overall survival (OS) was analysed. Results: seven hundred and three metastatic WT patients were registered in the SIOP 2001 database. Of them, 47 patients had a completely necrotic, local stage III WT: 45 lung metastases (11 combined localisations), 1 liver/peritoneal, and 1 tumour thrombus in the renal vein and the inferior vena cava with bilateral pulmonary arterial embolism. Abdominal radiotherapy was administered in 29 patients (62%; 29 flank/abdominal irradiation and 9 combined with lung irradiation). Eighteen patients did not receive radiotherapy. Median follow-up was 6.6 years (range 1–151 months). Two of the 47 patients (4%) developed disease recurrence in the lung (one combined with abdominal relapse) and eventually died of the disease. Both patients had received abdominal radiotherapy, one of them combined with lung irradiation. Five-year EFS and OS were 95% and 95%, respectively. Conclusions: the outcome of patients with stage IV, local stage III, completely necrotic Wilms tumours is excellent. Our results suggest that abdominal irradiation in this patient category may not be of added value in first-line treatment, consistent with the current recommendation in the SIOP–RTSG 2016 UMBRELLA protocol.

Clinical characteristics and outcomes of children with WAGR syndrome and Wilms tumor and/or nephroblastomatosis: The 30-year SIOP-RTSG experience

BACKGROUND

WAGR syndrome (Wilms tumor, aniridia, genitourinary anomalies, and range of developmental delays) is a rare contiguous gene deletion syndrome with a 45% to 60% risk of developing Wilms tumor (WT). Currently, surveillance and treatment recommendations are based on limited evidence.

METHODS

Clinical characteristics, treatments, and outcomes were analyzed for patients with WAGR and WT/nephroblastomatosis who were identified through International Society of Pediatric Oncology Renal Tumor Study Group (SIOP-RTSG) registries and the SIOP-RTSG network (1989-2019). Events were defined as relapse, metachronous tumors, or death.

RESULTS

Forty-three patients were identified. The median age at WT/nephroblastomatosis diagnosis was 22 months (range, 6-44 months). The overall stage was available for 40 patients, including 15 (37.5%) with bilateral disease and none with metastatic disease. Histology was available for 42 patients; 6 nephroblastomatosis without further WT and 36 WT, including 19 stromal WT (52.8%), 12 mixed WT (33.3%), 1 regressive WT (2.8%) and 2 other/indeterminable WT (5.6%). Blastemal type WT occurred in 2 patients (5.6%) after prolonged treatment for nephroblastomatosis; anaplasia was not reported. Nephrogenic rests were present in 78.9%. Among patients with WT, the 5-year event-free survival rate was 84.3% (95% confidence interval, 72.4%-98.1%), and the overall survival rate was 91.2% (95% confidence interval, 82.1%-100%). Events (n = 6) did not include relapse, but contralateral tumor development (n = 3) occurred up to 7 years after the initial diagnosis, and 3 deaths were related to hepatotoxicity (n = 2) and obstructive ileus (n = 1).

CONCLUSIONS

Patients with WAGR have a high rate of bilateral disease and no metastatic or anaplastic tumors. Although they can be treated according to existing WT protocols, intensive monitoring of toxicity and surveillance of the remaining kidney(s) are advised.

LAY SUMMARY

WAGR syndrome (Wilms tumor, aniridia, genitourinary anomalies, and range of developmental delays) is a rare genetic condition with an increased risk of developing Wilms tumor. In this study, 43 patients with WAGR and Wilms tumor (or Wilms tumor precursor lesions/nephroblastomatosis) were identified through the international registry of the International Society of Pediatric Oncology Renal Tumor Study Group (SIOP-RTSG) and the SIOP-RTSG network. In many patients (37.5%), both kidneys were affected. Disease spread to other organs (metastases) did not occur. Overall, this study demonstrates that patients with WAGR syndrome and Wilms tumor can be treated according to existing protocols. However, intensive monitoring of treatment complications and surveillance of the remaining kidney(s) are advised.

Preoperative Wilms tumor rupture in children

PURPOSE

According to the guidelines of International Society of Pediatric Oncology (SIOP) and National Wilms Tumor Study (NWTS), Wilms tumor with preoperative rupture should be classified as at least stage III. Few clinical reports can be found about preoperative Wilms tumor rupture. The purpose of this study was to investigate our experience on the diagnosis, treatment and prognosis of preoperative Wilms tumor rupture.

METHODS

Patients with Wilms tumor who underwent treatment according to the NWTS or SIOP protocol from January 2008 to September 2017 in Beijing Children's Hospital were reviewed retrospectively. The clinical signs of preoperative tumor rupture were acute abdominal pain, and/or fall of hemoglobin. The radiologic signs of preoperative tumor rupture are as follows: (1) retroperitoneal and/or intraperitoneal effusion; (2) acute hemorrhage located in the sub-capsular and/or perirenal space; (3) tumor fracture communicating with peritoneal effusion; (4) bloody ascites. Patients with clinical and radiologic signs of preoperative tumor rupture were selected. Patients having radiologic signs without clinical symptoms were also selected. The clinical data, treatments and outcomes were analyzed. Meanwhile, patients without preoperative Wilms tumor rupture during the same period were collected and analyzed.

RESULTS

565 Patients with Wilms tumor were registered in our hospital. Of these patients, 45 patients were diagnosed with preoperative ruptured Wilms tumor. All preoperative rupture were confirmed at surgery. Spontaneous tumor rupture occurred in 41 patients, the other 4 patients had traumatic history. Of the 45 patients, 41 were classified as stage III, 3 patients with pulmonary metastases were classified as stage IV, and one patient with bilateral tumors were classified as stage V. Of these patients with preoperative tumor rupture at stage III, 30 patients had clinical and radiologic signs of tumor rupture, the other 11 patients had radiologic signs without clinical symptoms. Among the 41 patients at stage III, 13 patients had immediate surgery without preoperative chemotherapy (immediate group), and 28 patients had delayed surgery after preoperative chemotherapy (delayed group). In immediate group, 12 patients had localized rupture, 1 patient underwent emergency surgery because of continuous bleeding. In delayed group, 4 had inferior vena cava tumor embolus (1 thrombus extended to inferior vena cava behind the liver, three thrombi got to the right atrium), 4 crossed the midline with large tumors, 20 had extensive rupture without localization. In immediate group, tumor recurrence and metastasis developed in 2 patients, and no death occurred. In the delayed group, tumor recurrence and metastasis developed in 8 patients, and 7 patients died. During the same period, 41 patients were classified as stage III without preoperative rupture. In the non-ruptured group, tumor recurrence and metastasis developed in 3 patients, and 4 patients died. The median survival time in the ruptured group (both immediate group and delayed group) and non-ruptured group were (85.1 ± 7.5) and (110.3 ± 5.6) months, and the 3-year cumulative survival rates were 75.1% and 89.6%, respectively. The overall survival rate between the ruptured and non-ruptured groups showed no statistic difference (P = 0.256). However, there was significant difference in recurrence or metastasis rate between the ruptured and non-ruptured groups (24.4% vs 7.3%; P = 0.031).

CONCLUSION

Contrast-enhanced computed tomography (CT) and ultrasonography (US) are of major value in the diagnosis of preoperative tumor rupture, and immediate surgery or delayed surgery are available therapeutic methods. The treatment plan was based on patients' general conditions, tumor size, position and impairment degree of tumor rupture, extent of invasion and experience of a multidisciplinary team (including surgeon and anesthesiologists). In our experience, for ruptured preoperative tumor diagnosed with stage III, the criteria for immediate surgery are as follows: tumor not acrossing the midline, tumor without inferior vena cava thrombus, localized rupture, being capable of complete resection. Selection criteria for delayed surgery after preoperative chemotherapy are as follows: large tumors, long inferior vena cava tumor thrombus, tumors infiltrating to surrounding organs, unlocalized rupture, tumors can not being resected completely. Additionally, patients with preoperative Wilms tumor rupture had an increased risk of postoperative recurrence or metastasis.

Investigating Wilms' Tumours Worldwide: A Report of the OxPLORE Collaboration-A Cross-Sectional Observational Study

BACKGROUND

Childhood cancer is neglected within global health. Oxford Pediatrics Linking Oncology Research with Electives describes early outcomes following collaboration between low- and high-income paediatric surgery and oncology centres. The aim of this paper is twofold: to describe the development of a medical student-led research collaboration; and to report on the experience of Wilms' tumour (WT).

METHODS

This cross-sectional observational study is reported as per STROBE guidelines. Collaborating centres included three tertiary hospitals in Tanzania, Rwanda and the UK. Data were submitted by medical students following retrospective patient note review of 2 years using a standardised data collection tool. Primary outcome was survival (point of discharge/death).

RESULTS

There were 104 patients with WT reported across all centres over the study period (Tanzania n = 71, Rwanda n = 26, UK n = 7). Survival was higher in the high-income institution [87% in Tanzania, 92% in Rwanda, 100% in the UK (X² 36.19, p < 0.0001)]. Given the short-term follow-up and retrospective study design, this likely underestimates the true discrepancy. Age at presentation was comparable at the two African sites but lower in the UK (one-way ANOVA, F = 0.2997, p = 0.74). Disease was more advanced in Tanzania at presentation (84% stage III-IV cf. 60% and 57% in Rwanda and UK, respectively, X² 7.57, p = 0.02). All patients had pre-operative chemotherapy, and a majority had nephrectomy. Post-operative morbidity was higher in lower resourced settings (X² 33.72, p < 0.0001). Methodology involving medical students and junior doctors proved time- and cost-effective. This collaboration was a valuable learning experience for students about global research networks.

CONCLUSIONS

This study demonstrates novel research methodology involving medical students collaborating across the global south and global north. The comparison of outcomes advocates, on an institutional level, for development in access to services and multidisciplinary treatment of WT.

Wilms tumor in patients with osteopathia striata with cranial sclerosis

Germline pathogenic variants in AMER1 cause osteopathia striata with cranial sclerosis (OSCS: OMIM 300373), an X-linked sclerosing bone disorder. Female heterozygotes exhibit metaphyseal striations in long bones, macrocephaly, cleft palate, and, occasionally, learning disability. Male hemizygotes typically manifest the condition as fetal or neonatal death. Somatically acquired variants in AMER1 are found in neoplastic tissue in 15-30% of patients with Wilms tumor; however, to date, only one individual with OSCS has been reported with a Wilms tumor. Here we present four cases of Wilms tumor in unrelated individuals with OSCS, including the single previously published case. We also report the first case of bilateral Wilms tumor in a patient with OSCS. Tumor tissue analysis showed no clear pattern of histological subtypes. In Beckwith-Wiedemann syndrome, which has a known predisposition to Wilms tumor development, clinical protocols have been developed for tumor surveillance. In the absence of further evidence, we propose a similar protocol for patients with OSCS to be instituted as an initial precautionary approach to tumor surveillance. Further evidence is needed to refine this protocol and to evaluate the possibility of development of other neoplasms later in life, in patients with OSCS.

Is it always Wilms' tumor? Localized cystic disease of the kidney in an infant: An extremely rare case report and review of the literature

Localized Cystic Disease of the Kidney (LCDK) is an extremely rare benign disease in pediatric population. Although its management is conservative and generally requires no treatment, the unfamiliarity with the disease can expose such patients to misdiagnosis as renal malignancies or uncertainty for proper treatment. We report such a case in an infant and review the current literature.

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.

Relapsed Wilms' tumor in pediatric patients: challenges in low- to middle-income countries-a single-center experience

BACKGROUND

Wilms' tumor (WT) affects one in 10,000 children and accounts for 5% of all childhood cancers. Although the overall relapse rate for children with WT has decreased to less than 15 %, the overall survival for patients with recurrent disease remains poor at approximately 50 %. The aim of the study to evaluate the outcome of relapsed Wilms' tumor pediatric patients treated at the National Cancer Institute (NCI), Egypt, between January 2008 and December 2015.

RESULTS

One hundred thirty (130) patients diagnosed with WT during the study period, thirty (23%) patients had relapsed. The median follow up period was 22.3 months (range 3.6-140 months). The Overall Survival (OS) was 30.9% while the event-free survival (EFS) was 29.8% at a 5-year follow up period. Median time from diagnosis to relapse was 14.4 months. A second complete remission was attained in 18/30 patients (60%). The outcome of the 30 patients; 11 are alive and 19 had died. Three factors in our univariate analysis were prognostically significant for survival after relapse. The first was radiotherapy given after relapse (p = 0.012). The 5-year EFS and OS for the group that received radiotherapy were 41.9% versus 16.7% and 11.1% respectively for those that did not. The second was the state of lymph nodes among patients with local stage III (p = 0.004). Lastly, when risk stratification has been applied retrospectively on our study group, it proved to be statistically significant (p = 0.029).

CONCLUSION

Among relapsed pediatric WT, radiotherapy improved survival at the time of relapse and local stage III with positive lymph nodes had the worst survival among other stage III patients.

Treatment of Wilms Tumor in Sub-Saharan Africa: Results of the Second French African Pediatric Oncology Group Study

PURPOSE

Multidisciplinary management of Wilms tumor has been defined through multicenter prospective studies and an average expected patient cure rate of 90%. In sub-Saharan Africa, such studies are uncommon. After the encouraging results of the first Groupe Franco-Africain d'Oncologie Pédiatrique (GFAOP) study, we report the results of the GFAOP-NEPHRO-02 study using an adaptation of the International Society of Paediatric Oncology 2001 protocol.

PATIENTS AND METHODS

From April 1, 2005, to March 31, 2011, seven African units participated in a nonrandomized prospective study. All patients who were referred with a clinical and radiologic diagnosis of renal tumor were screened. Those older than age 6 months and younger than 18 years with a unilateral tumor previously untreated were pre-included and received preoperative chemotherapy. Patients with unfavorable histology or with a tumor other than Wilms, or with a nonresponding stage IV tumor were excluded secondarily.

RESULTS

Three hundred thirteen patients were initially screened. Two hundred fifty-seven patients were pre-included and 169 with histologic confirmation of intermediate-risk nephroblastoma were registered in the study and administered postoperative treatment. Thirty-one percent of patients were classified as stage I, 38% stage II, 24% stage III, and 7% stage IV. Radiotherapy was not available for any stage III patients. Three-year overall survival rate was 72% for all study patients and 73% for those with localized disease.

CONCLUSION

It was possible to conduct sub-Saharan African multicenter therapeutic studies within the framework of GFAOP. Survival results were satisfactory. Improvements in procedure, data collection, and outcome are expected in a new study. Radiotherapy is needed to reduce the relapse rate in patients with stage III disease.

Agreement between clinicoradiological signs at diagnosis and radiohistological analysis after neoadjuvant chemotherapy of suspected Wilms tumor rupture: Consequences on therapeutic choices

INTRODUCTION

According to SIOP criteria, every patient presenting with preoperative Wilms tumor (WT) rupture must receive abdominal radiotherapy. Neoadjuvant chemotherapy reduces tumor volume and is responsible for the development of peritumoral capsule formation, which can mask tumor rupture on histological analysis, while it was clinically or radiologically obvious at diagnosis. Yet, there are no protocol recommendations for this particular presentation.

OBJECTIVES

Study the agreement between clinicoradiological signs and histological confirmation after neoadjuvant chemotherapy of suspected WT rupture and describe the therapeutic choices arising in consequence.

METHODS

Descriptive retrospective study on a monocentric series of patients with WT between June 1991 and August 2017.

RESULTS

Out of 71 patients, 28 presented with suspected tumor rupture. We observed good agreement between clinical and radiological signs of suspected rupture (κ coefficient: 0.67). However, we assessed poor agreement between these signs and histological conclusions after neoadjuvant chemotherapy (κ coefficient: 0.27). Only five patients with clinicoradiological signs were overtreated with radiotherapy while tumor rupture had been refuted after histological review. The notion of abdominal trauma and the presence of intraperitoneal effusion seemed to guide collegial decision to overtreat these patients. No statistical difference in survival between patients with and without suspicion of tumor rupture at diagnosis was observed.

CONCLUSION

This study highlights the need for recommendations in case of discrepancy between radiological and histological signs of rupture at diagnosis and after neoadjuvant chemotherapy. A study with stronger statistical power is necessary to define criteria that would lead to optimization of treatment in this context.

Indications and results of diagnostic biopsy in pediatric renal tumors: A retrospective analysis of 317 patients with critical review of SIOP guidelines

OBJECTIVES

According to the Renal Tumor Study Group (RTSG) of the International Society of Paediatric Oncology (SIOP), diagnostic biopsy of renal tumors prior to neoadjuvant chemotherapy is not mandatory unless the presentation is atypical for a Wilms tumor (WT). This study addresses the relevance of this strategy as well as the accuracy and safety of image-guided needle biopsy.

METHODS

Clinical, radiological, and pathological data from 317 children (141 males/176 females, mean age: 4 years, range, 0-17.6) consecutively treated in one SIOP-affiliated institution were retrospectively analyzed.

RESULTS

Presumptive chemotherapy for WT was decided for 182 patients (57% of the cohort), 24 (8%) were operated upfront, and 111 (35%) were biopsied at diagnosis. A non-WT was confirmed after surgery in 5/182 (3%), 11/24 (46%), and 28/111 (25%), respectively. Age at diagnosis was the most commonly (46%) used criterion to go for biopsy but a nine-year threshold should be retrospectively considered more relevant. Tumor volumes of clear cell sarcoma of the kidney and WT were significantly higher than those of other tumors (P = 0.002). The agreement between core-needle biopsy (CNB) and final histology was 99%. No significant morbidity was associated with CNB.

CONCLUSION

The use of SIOP criteria to identify patients eligible for presumptive WT neoadjuvant chemotherapy or upfront surgery avoided biopsy in 65% of children and led to a 97% rate of appropriate preoperative chemotherapy. Image-guided CNB is a safe and accurate diagnostic procedure. The relevance of SIOP biopsy criteria might be improved by using an older age threshold (9 years instead of 6 years) and by adding initial tumor volume.

Salidroside inhibits the growth, migration and invasion of Wilms' tumor cells through down-regulation of miR-891b

AIMS

Salidroside is a major functional component of Rhodiola rosea L. with a lot of pharmacological effects, including anti-tumor. The present work aimed to explore whether Salidroside could also exhibit anti-tumor functions in Wilms' tumor.

MAIN METHODS

WIT49 and RM1 cells were treated by various doses of Salidroside. CCK-8 assay, flow cytometry detection, colony formation assay, Transwell assay, RT-qPCR and Western blot analysis were conducted to measure WIT49 and RM1 cells proliferation, apoptosis, migration and invasion. The expression changes of miR-891b in response to Salidroside treatment were tested by RT-qPCR. Rescue assays were performed to test whether miR-891b was a downstream effector of Salidroside. Finally, the involvement of PI3K/AKT/mTOR and NF-κB signaling pathways was studied.

KEY FINDINGS

Salidroside with concentration of 80 μM significantly reduced WIT49 and RM1 cells viability, survival capacity, migration and invasion, and significantly induced apoptosis. Meanwhile, down-regulation of Cyclin D1, MMP-2 and Vimentin, up-regulations of p53 and p21, as well as cleavage of caspase-3 and -9 were observed in Salidroside-treated cell. miR-891b was down-regulated by Salidroside. And Salidroside did not suppress WIT49 and RM1 cells growth, migration and invasion when miR-891b was overexpressed. Also, the deactivation of PI3K/AKT/mTOR and NF-κB pathways induced by Salidroside was reversed by miR-891b overexpression.

SIGNIFICANCE

Salidroside inhibits Wilms' tumor cells growth, migration and invasion via down-regulating miR-891b, which leads to the deactivation of PI3K/AKT/mTOR and NF-κB signaling pathways.

Clear Cell Sarcoma of the Kidney

Clear cell sarcoma of the kidney is the second most common primary renal malignancy in childhood. It is histologically diverse, making accurate diagnosis challenging in some cases. Recent molecular studies have uncovered BCOR exon 15 internal tandem duplications in most cases, and YWHAE-NUTM2 fusion in a few cases, with the remaining cases having other genetic mutations, including BCOR-CCNB3 fusion and EGFR mutations. Although clear cell sarcoma of the kidney has no specific immunophenotype, several markers including cyclin D1, nerve growth factor receptor, and BCOR (BCL6 corepressor) have emerged as potential diagnostic aides. This review provides a concise account of recent advances in our understanding of clear cell sarcoma of the kidney to serve as a practical update for the practicing pathologist.

Clinical outcomes of children with Wilms tumor treated on a SIOP WT 2001 protocol in a tertiary care hospital in south India

INTRODUCTION

Wilms tumor is the most common pediatric renal malignancy. While developed countries have had excellent survival, it remains poorer by comparison in developing countries. The aim was to analyze the clinical outcome of children with Wilms tumor managed in a developing country from 2004 to 2014 by the SIOP WT 2001 protocol.

METHODS

Fifty-nine children with Wilms tumor managed by a SIOP WT 2001 regimen from 2004 to 2014 were analyzed.

RESULTS

The median age at presentation was 36 months, and 59% were boys. The average size of the tumor at presentation was 523 mL. Inferior vena cava thrombus was present in 11, distant metastases in 18, and bilateral tumors in six. Preoperative chemotherapy was given to all children after a diagnostic core needle biopsy. Preoperative chemotherapy reduced the tumor size to a mean of 208 mL and resolved venacaval thrombus in eight. Fifty-five children underwent definitive surgery while two children died during preoperative chemotherapy and two remained inoperable. All surviving children received adjuvant chemotherapy with 17 receiving radiotherapy as well. The overall survival (OS) was 80% and the event-free survival (EFS) was 73% after a mean follow up of 42 months after completion of therapy.

DISCUSSION

The tumor volumes at presentation and the incidence of venous tumor thrombosis in our cohort were much higher than those reported from developed countries. The incidence of metastatic disease at diagnosis (30.5%) was significantly higher than the 10-12% reported in Western data, but similar to that reported from various developing countries (14.1-31%). The OS in our cohort was 80% and the EFS was 73% with there being no events after 28 months. Although the survival rate for localized disease is similar to that in developed countries, the OS for metastatic disease was significantly less (50% vs. 75%). We also found that using an upfront posterior flank core biopsy was safe and beneficial for differentiating Wilms tumor from other pediatric renal tumors that are less chemosensitive.

CONCLUSION

In a resource-restricted environment such as ours, the SIOP WT 2001 protocol has been found to show excellent results.

Pediatric Solid Tumors in Resource-Constrained Settings: A Review of Available Evidence on Management, Outcomes, and Barriers to Care

International disparities in outcomes from pediatric solid tumors remain striking. Herein, we review the current literature regarding management, outcomes, and barriers to care for pediatric solid tumors in low- and middle-income countries (LMICs). In sub-Saharan Africa, Wilms Tumor represents the most commonly encountered solid tumor of childhood and has been the primary target of recent efforts to improve outcomes in low-resource settings. Aggressive and treatment-resistant tumor biology may play a role in poor outcomes within certain populations, but socioeconomic barriers remain the principal drivers of preventable mortality. Management protocols that include measures to address socioeconomic barriers have demonstrated early success in reducing abandonment of therapy. Further work is required to improve infrastructure and general pediatric care to address disparities.

The role of solute carrier (SLC) transporters in actinomycin D pharmacokinetics in paediatric cancer patients

BACKGROUND

Actinomycin D is used for treatment of paediatric cancers; however, a large inter-patient pharmacokinetic (PK) variability and hepatotoxicity are significant limitations to its use and warrant further investigation. Elimination of actinomycin D may be mediated by transporters, as the drug does not seem to undergo significant metabolism. We investigated the role of solute carrier (SLC) transporters in actinomycin D PK.

METHODS

Fourteen key SLCs were screened through probe substrate uptake inhibition by actinomycin D in HEK293 cells. Uptake of actinomycin D was further studied in candidate SLCs by measuring intracellular actinomycin D using a validated LCMS assay. Pharmacogenetic analysis was conducted for 60 patients (Clinical trial: NCT00900354), who were genotyped for SNPs for OAT4 and PEPT2.

RESULTS

OAT4, OCT2, OCT3 and PEPT2 showed significantly lower probe substrate uptake (mean ± SD 75.0 ± 3.5% (p < 0.0001), 74.8 ± 11.2% (p = 0.001), 81.2 ± 14.0% (p = 0.0083) and 70.7 ± 5.7% (p = 0.0188)) compared to that of control. Intracellular accumulation of actinomycin D was greater compared to vector control in OAT4-transfected cells by 1.5- and 1.4-fold at 10 min (p = 0.01) and 20 min (p = 0.03), and in PEPT2-transfected cells by 1.5- and 1.7-fold at 10 min (p = 0.047) and 20 min (p = 0.043), respectively. Subsequent clinical study did not find a significant association between OAT4 rs11231809 and PEPT2 rs2257212 genotypes, and actinomycin D PK parameters such as clearance (CL) and volume of distribution (V_d).

CONCLUSION

Transport of actinomycin D was mediated by OAT4 and PEPT2 in vitro. There was a lack of clinical significance of OAT4 and PEPT2 genotypes as predictors of actinomycin D disposition in paediatric cancer patients.

Evaluation of boost irradiation in patients with intermediate-risk stage III Wilms tumour with positive lymph nodes only: Results from the SIOP-WT-2001 Registry

OBJECTIVE

To evaluate the value of radiotherapy boost omission in patients with intermediate-risk, stage III Wilms tumours (WT) with positive lymph nodes (LN).

METHODS AND MATERIALS

All patients with intermediate-risk, stage III (LN positive) WT consecutively registered in the SIOP-WT-2001 study were included in this analysis. Endpoints were 5-year event-free survival (EFS), loco-regional control (LRC) and overall survival (OS).

RESULTS

Between June 2001 and May 2015, 2,569 patients with stage I to III WT after preoperative chemotherapy were registered in the SIOP-WT-2001 study. Five hundred and twenty-three (20%) had stage III disease, of which 113 patients had stage III due to positive LN only. Of those, 101 (89%) received radiotherapy, 36 of which (36%) received, apart from flank irradiation, a boost dose to the LN positive area. Four patients (4%) did not receive any adjuvant radiotherapy. In eight patients information on radiotherapy was not available. With a median follow-up of 71 months, no difference in 5-year EFS (84% vs. 83%, P = 0.77) and LRC (96% vs. 97%, P = 0.91) was observed between patients receiving a radiotherapy boost and those without boost, respectively. Five-year OS, including salvage therapy, was excellent (boost vs. no boost: 97% vs. 95%, P = 0.58).

CONCLUSIONS

Outcome data demonstrate that omission of the radiotherapy boost to the loco-regional positive lymph nodes in patients with intermediate-risk, stage III WT who receive preoperative chemotherapy and postoperative flank irradiation (14.4 Gy) can be considered a safe approach for future SIOP protocols.

Position paper: Rationale for the treatment of children with CCSK in the UMBRELLA SIOP-RTSG 2016 protocol

The International Society of Paediatric Oncology-Renal Tumour Study Group (SIOP-RTSG) has developed a new protocol for the diagnosis, treatment, and follow-up monitoring of childhood renal tumours - the UMBRELLA SIOP-RTSG 2016 protocol (the UMBRELLA protocol). This protocol has been designed to continue international collaboration in the treatment of childhood renal tumours and will be implemented in over 50 different countries. Clear cell sarcoma of the kidney, which is a rare paediatric renal tumour that most commonly occurs in children between 2 and 4 years of age, is specifically addressed in the UMBRELLA protocol.

HMGA2 overexpression predicts relapse susceptibility of blastemal Wilms tumor patients

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

Position paper: Rationale for the treatment of Wilms tumour in the UMBRELLA SIOP-RTSG 2016 protocol

The Renal Tumour Study Group of the International Society of Paediatric Oncology (SIOP-RTSG) has developed a new protocol for the diagnosis and treatment of childhood renal tumours, the UMBRELLA SIOP-RTSG 2016 (the UMBRELLA protocol), to continue international collaboration in the treatment of childhood renal tumours. This protocol will support integrated biomarker and imaging research, focussing on assessing the independent prognostic value of genomic changes within the tumour and the volume of the blastemal component that survives preoperative chemotherapy. Treatment guidelines for Wilms tumours in the UMBRELLA protocol include recommendations for localized, metastatic, and bilateral disease, for all age groups, and for relapsed disease. These recommendations have been established by a multidisciplinary panel of leading experts on renal tumours within the SIOP-RTSG. The UMBRELLA protocol should promote international collaboration and research and serve as the SIOP-RTSG best available treatment standard.

Results of the First Prospective Multi-institutional Treatment Study in Children With Bilateral Wilms Tumor (AREN0534): A Report From the Children's Oncology Group

OBJECTIVE

The Children's Oncology Group study AREN0534 aimed to improve event-free survival (EFS) and overall survival (OS) while preserving renal tissue by intensifying preoperative chemotherapy, completing definitive surgery by 12 weeks from diagnosis, and modifying postoperative chemotherapy based on histologic response.

BACKGROUND

No prospective therapeutic clinic trials in children with bilateral Wilms tumors (BWT) exist. Historical outcomes for this group were poor and often involved prolonged chemotherapy; on NWTS-5, 4-year EFS for all children with BWT was 56%.

METHODS

Patients were enrolled and imaging studies were centrally reviewed to assess for bilateral renal lesions. They were treated with 3-drug induction chemotherapy (vincristine, dactinomycin, and doxorubicin) for 6 or 12 weeks based on radiographic response followed by surgery and further chemotherapy determined by histology. Radiation therapy was provided for postchemotherapy stage III and IV disease.

RESULTS

One hundred eighty-nine of 208 patients were evaluable. Four-year EFS and OS were 82.1% (95% CI: 73.5%-90.8%) and 94.9% (95% CI: 90.1%-99.7%. Twenty-three patients relapsed and 7 had disease progression. After induction chemotherapy 163 of 189 (84.0%) underwent definitive surgical treatment in at least 1 kidney by 12 weeks and 39% retained parts of both kidneys. Surgical approaches included: unilateral total nephrectomy with contralateral partial nephrectomy (48%), bilateral partial nephrectomy (35%), unilateral total nephrectomy (10.5%), unilateral partial nephrectomy (4%), and bilateral total nephrectomies (2.5%).

CONCLUSION

This treatment approach including standardized 3-drug preoperative chemotherapy, surgical resection within 12 weeks of diagnosis and response and histology-based postoperative therapy improved EFS and OS and preservation of renal parenchyma compared with historical outcomes for children with BWT.

Is Pre-operative Chemotherapy Desirable in all Patients of Wilms' Tumor?

The timing and role of chemotherapy in the management of Wilms' tumor has long been the matter of debate, with different groups showing equally comparable and encouraging results. Over the last decade, however, both the ideol-ogies seem to be converging and the attempt has been to identify groups benefitting with pre-operative chemotherapy, as well as those, where upfront resection should be attempted. In this article authors intend to discuss pros and cons of both the strategies and their applicability in a resource poor setting in developing countries like India.

Functional KRAS mutations and a potential role for PI3K/AKT activation in Wilms tumors

Wilms tumor (WT) is the most common renal neoplasm of childhood and affects 1 in 10 000 children aged less than 15 years. These embryonal tumors are thought to arise from primitive nephrogenic rests that derive from the metanephric mesenchyme during kidney development and are characterized partly by increased Wnt/β-catenin signaling. We previously showed that coordinate activation of Ras and β-catenin accelerates the growth and metastatic progression of a murine WT model. Here, we show that activating KRAS mutations can be found in human WT. In addition, high levels of phosphorylated AKT are present in the majority of WT. We further show in a mouse model and in renal epithelial cells that Ras cooperates with β-catenin to drive metastatic disease progression and promotes in vitro tumor cell growth, migration, and colony formation in soft agar. Cellular transformation and metastatic disease progression of WT cells are in part dependent on PI3K/AKT activation and are inhibited via pharmacological inhibition of this pathway. Our studies suggest both KRAS mutations and AKT activation are present in WT and may represent novel therapeutic targets for this disease.

Pencil beam scanning proton therapy for treatment of the retroperitoneum after nephrectomy for Wilms tumor: A dosimetric comparison study

BACKGROUND

Multimodality treatment for patients with Wilms tumor has improved patient survival, but is associated with acute and long-term toxicity, partially due to irradiation. Proton therapy using pencil beam scanning (PBS) is a promising technique to reduce dose to organs at risk (OAR). In this study, we evaluate PBS plans for postoperative irradiation in patients with Wilms tumor.

PROCEDURE

Patients were treated with anterior-posterior-posterior-anterior (AP-PA) photon fields encompassing the preoperative tumor volume. Patients requiring whole lung irradiation were treated with AP-PA photon fields covering the bilateral lungs. Prescription doses were generally 1,080 and 1,200 cGy, respectively. Flank PBS plans encompassing the ipsilateral retroperitoneum and para-arotic nodes were generated for dosimetric evaluation.

RESULTS

Treatment records and comparison plans of 11 patients were reviewed. Mean dose and median dose to 50% or more of the contralateral kidney (D50) were 135 cGy and 139 cGy with photons and 52 cGy relative biological effectiveness (RBE) (P = 0.009) and 5 cGy RBE (P = 0.000001) with PBS. Mean dose and median D50 to bowel was 639 cGy and 979 cGy with photons and 379 cGy RBE (P = 0.001) and 47 cGy RBE (P = 0.004) with PBS. Mean dose and median D50 to the liver were 755 cGy and 1,013 cGy with photons and 411 cGy RBE (P = 0.02) and 132 cGy RBE (P = 0.02) with PBS. For patients with right-sided tumors, mean liver dose following sequential whole lung irradiation was 1,252 cGy with photons and 845 cGy RBE (P = 0.04) with PBS.

DISCUSSIONS

PBS proton therapy is a feasible method for irradiating the retroperitoneum and provides significant sparing of dose to critical OAR. This may translate to improved long-term health outcomes for patients and warrants further clinical investigation.

Predictive factor for intraoperative tumor rupture of Wilms tumor

PURPOSE

For Wilms tumor, intraoperative tumor rupture with wide tumor spillage during surgical manipulation raises the classification to stage 3. Then, postoperative chemotherapy must be more intensive, and abdominal radiotherapy is added. Therefore, intraoperative tumor rupture should be avoided if possible. However, predictive factors for intraoperative tumor rupture have not been sufficiently described. Here we examined the risk factors for intraoperative tumor rupture.

METHODS

Patients with Wilms tumor who underwent treatment according to the National Wilms Tumor Study or the Japanese Wilms Tumor Study protocol at our institution were reviewed retrospectively. Collected cases were categorized into two groups: the ruptured group and the non-ruptured group. Risk factors for intraoperative tumor rupture, including the ratio of the tumor area to the abdominal area in a preoperative single horizontal computed tomography slice (T/A ratio), were investigated in both groups.

RESULTS

The two groups were not different in age, body weight, tumor laterality, sex, or histological distribution. The T/A ratio in the ruptured group was significantly higher than that in the non-ruptured group. Receiver operating characteristic curve analysis identified a discriminative value for a T/A ratio >0.5.

CONCLUSION

The T/A ratio can be a predictive factor for intraoperative tumor rupture of Wilms tumor.

Synovial sarcoma of kidney in a child: A rare presentation

There are no reported cases in the literature of primary renal synovial sarcoma in pediatric patients. The management of renal synovial sarcoma has been extrapolated from the management of soft tissue sarcomas at other sites. We present a 4-year-old female who was suspected to have Wilms’ tumor. The patient underwent guided biopsy as she did not respond to neoadjuvant chemotherapy for Wilms’ tumor. The biopsy was consistent with primary renal synovial sarcoma. The child was treated with change in her neoadjuvant chemotherapy regimen and surgery. The diagnosis of synovial sarcoma was confirmed by demonstrating the t (X, 18) translocation using polymerase chain reaction.

Considerations in the Diagnosis and Management of Pediatric Patients With Favorable Histology Wilms Tumor Who Present With Only Pulmonary Nodules

More than 70% of children with stage IV, favorable histology (FH) Wilms tumor will be relapse-free survivors 16 years after diagnosis. Successful treatment generally includes whole lung radiation therapy and doxorubicin. Such therapy is associated with adverse, long-term effects, including impaired pulmonary function, congestive heart failure, and second malignant neoplasms, especially breast cancer. Cooperative groups have adopted a risk-based approach to the treatment of these patients. It is important to recall the good overall prognosis for this group before recommendations for intensification are made based on preliminary data and in the absence of histological confirmation of persistent malignant disease.

[Clear cell sarcoma of kidney in children]

Clear cell sarcoma of the kidney (CCSK) is a rare tumor that is diagnosed most often in children between 2- and 4-years-old of age. Usually, patients with CCSK are treated in international study for intrarenal tumors, preferentially Wilms tumor, according to bad histopronostic group. The purpose of this paper is to review the most important features in 2015 about epidemiology, radiology, anatomopathology and genetic of CCSK, and above all a synthesis about successive treatment strategies with their results. Second most common pediatric renal tumor in children less than 5-years-old, its prognosis has improved dramatically in recent years with the use of anthracyclines.

Development of a physiologically based pharmacokinetic model of actinomycin D in children with cancer

Aims

Use of the anti‐tumour antibiotic actinomycin D is associated with development of hepatotoxicity, particularly in young children. A paucity of actinomycin D pharmacokinetic data make it challenging to develop a sound rationale for defining dosing regimens in younger patients. The study aim was to develop a physiologically based pharmacokinetic (PBPK) model using a combination of data from the literature and generated from experimental analyses.

Methods

Assays to determine actinomycin D Log P, blood:plasma partition ratio and ABCB1 kinetics were conducted. These data were combined with physiochemical properties sourced from the literature to generate a compound file for use within the modelling‐simulation software Simcyp (version 14 release 1). For simulation, information was taken from two datasets, one from 117 patients under the age of 21 and one from 20 patients aged 16–48.

Results

The final model incorporated clinical renal and biliary clearance data and an additional systemic clearance value. The mean AUC_0‐26h of simulated subjects was within 1.25‐fold of the observed AUC_0‐26h (84 ng h ml⁻¹ simulated vs. 93 ng h ml⁻¹ observed). For the younger age ranges, AUC predictions were within two‐fold of observed values, with simulated data from six of the eight age/dose ranges falling within 15% of observed data. Simulated values for actinomycin D AUC_0‐26h and clearance in infants aged 0–12 months ranged from 104 to 115 ng h ml⁻¹ and 3.5–3.8 l h⁻¹, respectively.

Conclusions

The model has potential utility for prediction of actinomycin D exposure in younger patients and may help guide future dosing. However, additional independent data from neonates and infants is needed for further validation. Physiological differences between paediatric cancer patients and healthy children also need to be further characterized and incorporated into PBPK models.

Wilms tumor: Successes and challenges in management outside of cooperative clinical trials

OBJECTIVE/BACKGROUND

Management of Wilms tumor (WT) in children depends on a multidisciplinary approach to treatment, and outcomes have significantly improved as reported by cooperative group clinical trials. Here, we review the clinical outcomes of patients with WT and identify challenges and barriers encountered in multidisciplinary management outside of cooperative clinical trials.

METHODS

We retrospectively reviewed the clinical records of 35 children with WT treated between April 2002 and June 2013 at the Children's Cancer Institute in Lebanon.

RESULTS

Upfront resection was performed in 23 cases. Biopsies were performed for Stage V tumors (n=4), those with unresectable tumors or inferior vena caval thrombus (n=5), and patients who had partial surgery performed elsewhere prior to presentation (n=2). One patient died due to toxicity prior to surgery. The tumor was Stage I in eight patients, Stage II in five patients, Stages III and IV in nine patients each, and bilateral (Stage V) in four patients. Adherence to The National Wilms Tumor Study-5 recommendations was adequate. At the time of analysis, 30 patients were free of disease and four patients had relapse-all having metastatic disease initially.

CONCLUSION

The National Wilms Tumor Study-5 therapy resulted in favorable outcomes in children with nonmetastatic Wilms tumor in the setting of a multidisciplinary approach to therapy and resolution of financial barriers to medical care. Upstaging due to prior intervention and lung radiation therapy to all those with computed tomography-detected lung nodules may both have resulted in overtreatment of a subset of patients. Finally, the relatively high incidence of bilateral tumors suggests the need for further genetic and molecular studies in this patient population.

Risk stratification for wilms tumor: current approach and future directions

Wilms tumor, or nephroblastoma, has provided a paradigm for progressive improvement in clinical outcomes achieved through serial cooperative group studies. With modern surgery, chemotherapy, and radiation therapy approaches, the overall survival rate for patients with Wilms tumor has reached 90%. Remarkably, the increase in survival has been achieved with a reduction in therapy for most patient subgroups, leading not only to more survivors, but also to healthier survivors. A key contributor to improved outcomes has been the development of clinical and biologic prognostic markers that have enabled risk-directed therapy. Whereas the early cooperative group studies used only tumor stage for risk stratification, current Children's Oncology Group (COG) and International Society of Pediatric Oncology (SIOP) protocols employ a multitude of prognostic factors to guide therapy. Prognostic factors used in the current generation of COG studies include stage, histology, patient age, tumor weight, completeness of lung nodule response, and loss of heterozygosity at chromosomes 1p and 16q. Future COG studies seek to incorporate gain of chromosome 1q and methylation pattern of chromosome 11p15 into the risk classification schema. Prognostic factors used in the current SIOP studies include stage, histology, tumor volume, and responsiveness to therapy. Future SIOP studies seek to incorporate absolute blastemal volume and novel molecular markers for resistant blastema into the risk stratification approach.

Omission of doxorubicin from the treatment of stage II-III, intermediate-risk Wilms' tumour (SIOP WT 2001): an open-label, non-inferiority, randomised controlled trial

BACKGROUND

Before this study started, the standard postoperative chemotherapy regimen for stage II-III Wilms' tumour pretreated with chemotherapy was to include doxorubicin. However, avoidance of doxorubicin-related cardiotoxicity effects is important to improve long-term outcomes for childhood cancers that have excellent prognosis. We aimed to assess whether doxorubicin can be omitted safely from chemotherapy for stage II-III, histological intermediate-risk Wilms' tumour when a newly defined high-risk blastemal subtype was excluded from randomisation.

METHODS

For this international, multicentre, open-label, non-inferiority, phase 3, randomised SIOP WT 2001 trial, we recruited children aged 6 months to 18 years at the time of diagnosis of a primary renal tumour from 251 hospitals in 26 countries who had received 4 weeks of preoperative chemotherapy with vincristine and actinomycin D. Children with stage II-III intermediate-risk Wilms' tumours assessed after delayed nephrectomy were randomly assigned (1:1) by a minimisation technique to receive vincristine 1·5 mg/m(2) at weeks 1-8, 11, 12, 14, 15, 17, 18, 20, 21, 23, 24, 26, and 27, plus actinomycin D 45 μg/kg every 3 weeks from week 2, either with five doses of doxorubicin 50 mg/m(2) given every 6 weeks from week 2 (standard treatment) or without doxorubicin (experimental treatment). The primary endpoint was non-inferiority of event-free survival at 2 years, analysed by intention to treat and a margin of 10%. Assessment of safety and adverse events included systematic monitoring of hepatic toxicity and cardiotoxicity. This trial is registered with EudraCT, number 2007-004591-39, and is closed to new participants.

FINDINGS

Between Nov 1, 2001, and Dec 16, 2009, we recruited 583 patients, 341 with stage II and 242 with stage III tumours, and randomly assigned 291 children to treatment including doxorubicin, and 292 children to treatment excluding doxorubicin. Median follow-up was 60·8 months (IQR 40·8-79·8). 2 year event-free survival was 92·6% (95% CI 89·6-95·7) for treatment including doxorubicin and 88·2% (84·5-92·1) for treatment excluding doxorubicin, a difference of 4·4% (95% CI 0·4-9·3) that did not exceed the predefined 10% margin. 5 year overall survival was 96·5% (94·3-98·8) for treatment including doxorubicin and 95·8% (93·3-98·4) for treatment excluding doxorubicin. Four children died from a treatment-related toxic effect; one (<1%) of 291 receiving treatment including doxorubicin died of sepsis, three (1%) of 292 receiving treatment excluding doxorubicin died of varicella, metabolic seizure, and sepsis during treatment for relapse. 17 patients (3%) had hepatic veno-occlusive disease. Cardiotoxic effects were reported in 15 (5%) of 291 children receiving treatment including doxorubicin. 12 children receiving treatment including doxorubicin, and ten children receiving treatment excluding doxorubicin, died, with the remaining deaths from tumour recurrence.

INTERPRETATION

Doxorubicin does not need to be included in treatment of stage II-III intermediate risk Wilms' tumour when the histological response to preoperative chemotherapy is incorporated into the risk stratification.

FUNDING

See Acknowledgments for funders.