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.

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

Pediatric Blood & CancerVolume 67, Issue 11 e28411 LETTER TO THE EDITOR Summary of COVID-19 clinical practice adjustments across select institutions Liora Schultz, Corresponding Author Liora Schultz [email protected] orcid.org/0000-0001-9512-7597 Department of Pediatrics, Stanford University School of Medicine, Stanford, California Correspondence Liora Schultz, Stanford University, 1000 Welch Rd., Suite 300, Palo Alto, CA 94304, USA. Email: [email protected]Search for more papers by this authorMichael P. Link, Michael P. Link Department of Pediatrics, Stanford University School of Medicine, Stanford, CaliforniaSearch for more papers by this authorSusan Rheingold, Susan Rheingold orcid.org/0000-0001-8025-6767 Children's Hospital of Philadelphia, Philadelphia, PennsylvaniaSearch for more papers by this authorDouglas S. Hawkins, Douglas S. Hawkins Seattle Children's Hospital, Seattle, WashingtonSearch for more papers by this authorJeffrey S. Dome, Jeffrey S. Dome Children's National Hospital, George Washington University School of Medicine and Health Sciences, Washington, District of ColumbiaSearch for more papers by this authorJonathan Wickiser, Jonathan Wickiser UT Southwestern, Dallas, TexasSearch for more papers by this authorAndrew L. Kung, Andrew L. Kung orcid.org/0000-0002-9091-488X Memorial Sloan Kettering Cancer Center, New York, New YorkSearch for more papers by this authorTara O. Henderson, Tara O. Henderson University of Chicago Comer Children's Hospital, Chicago, IllinoisSearch for more papers by this authorCatherine Aftandilian, Catherine Aftandilian orcid.org/0000-0001-9775-2839 Department of Pediatrics, Stanford University School of Medicine, Stanford, CaliforniaSearch for more papers by this author Liora Schultz, Corresponding Author Liora Schultz [email protected] orcid.org/0000-0001-9512-7597 Department of Pediatrics, Stanford University School of Medicine, Stanford, California Correspondence Liora Schultz, Stanford University, 1000 Welch Rd., Suite 300, Palo Alto, CA 94304, USA. Email: [email protected]Search for more papers by this authorMichael P. Link, Michael P. Link Department of Pediatrics, Stanford University School of Medicine, Stanford, CaliforniaSearch for more papers by this authorSusan Rheingold, Susan Rheingold orcid.org/0000-0001-8025-6767 Children's Hospital of Philadelphia, Philadelphia, PennsylvaniaSearch for more papers by this authorDouglas S. Hawkins, Douglas S. Hawkins Seattle Children's Hospital, Seattle, WashingtonSearch for more papers by this authorJeffrey S. Dome, Jeffrey S. Dome Children's National Hospital, George Washington University School of Medicine and Health Sciences, Washington, District of ColumbiaSearch for more papers by this authorJonathan Wickiser, Jonathan Wickiser UT Southwestern, Dallas, TexasSearch for more papers by this authorAndrew L. Kung, Andrew L. Kung orcid.org/0000-0002-9091-488X Memorial Sloan Kettering Cancer Center, New York, New YorkSearch for more papers by this authorTara O. Henderson, Tara O. Henderson University of Chicago Comer Children's Hospital, Chicago, IllinoisSearch for more papers by this authorCatherine Aftandilian, Catherine Aftandilian orcid.org/0000-0001-9775-2839 Department of Pediatrics, Stanford University School of Medicine, Stanford, CaliforniaSearch for more papers by this author First published: 19 July 2020 https://doi.org/10.1002/pbc.28411Citations: 3Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onEmailFacebookTwitterLinkedInRedditWechat No abstract is available for this article.Citing Literature Volume67, Issue11November 2020e28411 RelatedInformation

A 14-year-old male presented with abdominal pain. Imaging illustrated a left-sided adrenal mass; he underwent a left nephrectomy, confirming an extra-adrenal PGL. Germline genetic testing revealed a heterozygous, likely pathogenic mutation in the SDHB gene. The patient’s family subsequently underwent genetic testing; his mother and sister were both positive for the familial SDHB mutation. Cascade testing for the proband’s maternal aunt and maternal grandparents was negative for the familial mutation. SNP genotyping was used to confirm relationships. This is the second reported case of a de novo SDHB gene mutation and the first reported case of a confirmed de novo mutation in a patient who was not the initial proband. As SDHB -associated PGLs and PCCs are expected to be more aggressive and malignant, it is imperative to identify patients with SDHB mutations early. Given that many patients with germline mutations have no family history of PGL of PCC, the possibility of de novo mutations must be considered. Further studies are needed to determine the rate of de novo mutation in SDHB and other SDH -complex genes. Up to 41% of patients with paragangliomas (PGL) or pheochromocytomas (PCC) have an identifiable hereditary cancer predisposition syndrome. Mutations in 12 genes are known to increase the risk of PGL and/or PCC; however, the de novo rate is mostly unknown. Only one case report exists of a de novo SDHB mutation. We present the second case of a family with a de novo SDHB mutation.

Children with metastatic hepatoblastoma have a poor prognosis, even with dose intensification of cisplatin and doxorubicin. Vincristine and irinotecan have demonstrated activity in high risk disease. This report describes a 3-year-old girl with metastatic hepatoblastoma with unresectable disease after 5 cycles of cisplatin, 5-fluorouracil, vincristine, and doxorubicin who had a complete response of her metastatic disease to vincristine and irinotecan (intravenous and oral forms), allowing surgical resection of her liver disease. She remains in remission 48 months since therapy completion.

A 2.2-kg female infant is born at 28 4/7 weeks’ gestation to a 21-year-old gravida 1, para 0 woman with adequate prenatal care. During pregnancy, the mother is treated for Chlamydia with repeat negative cultures. She has negative serologies and a normal fetal ultrasonographic scan at 20 weeks’ gestation. Delivery is via cesarean section due to premature labor and frank breech presentation. At delivery, the infant is noted to have no respiratory effort and a large sacrococcygeal mass (Fig 1) . Positive pressure ventilation is started and the infant undergoes intubation 3 minutes after birth. Figure 1. Infant at delivery noted to have large sacrococcygeal teratoma. The admission physical examination findings are significant for a sacrococcygeal nodular, firm and nonpulsatile 20×30–cm mass, with minimal ulceration that is displacing the lower limbs anteriorly. Magnetic resonance imaging (MRI) of the pelvis shows a presacral mass with a large external component and relatively small internal component; the cephalad portion of the mass occurs at the level of L5, splaying the aortic bifurcation (Fig 2) . The infant’s vital signs are stable with minimal ventilatory support. Laboratory studies are positive for anemia (hemoglobin 11.4 g/dL [114 g/L]), a normal α-fetoprotein (AFP) level for gestational age (60,500 ng/mL [60,500 μg/L]), and a slightly elevated aspartate aminotransferase level (141 IU/L [2.35 μkat/L]). Figure 2. Magnetic resonance imaging scan of the pelvis showed a presacral mass (red arrow) with a large external component and relatively small internal component. On day 2 after birth, the infant develops hypotension and worsening respiratory failure; she is started on inotropes and high-frequency oscillation. The lesion becomes more tense and darker in color, concerning for intralesional hemorrhage. The infant also develops thrombocytopenia (platelets 66,000/μL [60×109/L]) and receives multiple platelet and red blood cell transfusions in preparation for surgery. Resection of the mass …

Background: Sacrococcygeal teratoma (SCT) is the most common germ cell tumor (GCT) of infancy. Up to 35% of infants may have malignant elements. The standard of care for SCT with malignant elements (SCT-ME) has been surgery and chemotherapy. However, cases where lowstage SCT-ME have been successfully observed following resection have been reported.Procedure: To better understand the outcomes of low-stage SCT-ME that do not receive chemotherapy, we reviewed SCT pathology reports from five children's hospitals from 1999 to 2009. Information regarding staging workup, tumor markers, treatment, and outcome was collected for patients with stage I or II SCT-ME. An English language literature review was also performed.Results: Seventy-four SCT were identified: 51 stage I and 23 stage II; 13 (18%) were SCT-ME: 5 stage I and 8 stage II; four stage I and four stage II tumors were not treated with chemotherapy. No stage I tumors recurred; all of the stage II tumors recurred and were successfully salvaged, two had no ME at recurrence. We identified another 10 stage I SCT-ME in the literature managed with active surveillance-two recurred and were successfully treated with surgery and chemotherapy.Conclusions: Overall, of the 14 cases of stage I SCT-ME, 12 survived with no recurrence and the two who did recur were successfully treated with platinum-based chemotherapy (EFS = 86%, overall survival [OS] = 100%); this suggests that patients with stage I SCT-ME could be observed after surgery and treated only upon recurrence. Stage II SCT-ME require further study in a clinical trial setting.

This study aims to identify novel therapeutic targets for nonseminomatous pediatric germ cell tumors (GCTs). GCTs are the most common cancer in young men, and affect both children and adolescents. They are histologically classified into two types: seminomatous GCTs (SGCTs), which are undifferentiated, and non-seminomatous GCTs (NSGCTs), which exhibit differentiation. Although cisplatin treatment is effective for many types of GCTs, cisplatin resistance, which is especially common in NSGCTs, confers poor prognosis for affected patients. However, because the signaling pathways and genes responsible for the development of different types of GCTs are not well-understood, few targeted therapies exist for GCTs, and no specific therapies exist for NSGCTs. Therefore, novel therapies to specifically target NSGCTs are needed. To determine a targetable pathway that is activated in GCTs, we used quantitative RT-PCR to measure the expression of growth factor receptors in pediatric GCTs, immunohistochemistry (IHC) on a panel of clinically annotated germ cell tumors, and Western blot as well as cell viability assays on NSGCT cell lines (NCCIT and NTERA-2) to determine the effect of inhibition of two signaling pathways on cell viability. Our RT-PCR results showed that multiple members of the EGF and FGF receptor families are expressed at higher levels in NSGCTs than SGCTs. In addition, we found that EGF and FGF2 stimulate Ras-MAPK as well as PI3K/mTOR signaling in NSGCT cell lines. Based on IHC staining of phosphorylated ERK1/2, mTOR, and S6 ribosomal protein, we showed that both the Ras-MAPK and PI3K-mTOR pathways are activated at higher levels in NSGCTs than SGCTs. The results suggested that inhibiting EGFR as well as mTORC1 may be effective in impairing the growth and survival of NSGCT cell lines. To test this hypothesis, we examined the effects of two small molecule inhibitors of EGFR and mTOR signaling, erlotinib and rapamycin, respectively, on the survival of NCCIT and NTERA-2 cell lines. We verified by Western blot that erlotinib inhibits components of the Ras-MAPK pathway in NSGCT cell lines, while rapamycin inhibits components of the PI3K-mTOR pathway. Cell survival experiments showed that while treatment with rapamycin or erlotinib alone decreased cell viability, sufficient reduction of survival could only be achieved with high concentrations that are not clinically feasible. However, a combination treatment of erlotinib and rapamycin synergistically inhibited the growth of the two NSGCT cell lines at clinically achievable concentrations. Our findings showed that NSGCTs are dependent on EGFR and mTOR signaling in vitro, and suggest that targeting these signaling pathways may be a promising therapy to specifically target chemoresistant NSGCTs. Citation Format: Albert Budhipramono, Dinesh Rakheja, Kenneth S. Chen, Nicholas Fustino, Abhay Shukla, Jonathan Wickiser, Theodore Laetsch, James F. Amatruda. EGFR and mTORC1 are novel therapeutic targets in nonseminomatous germ cell tumors. [abstract]. In: Proceedings of the AACR Special Conference on Advances in Pediatric Cancer Research: From Mechanisms and Models to Treatment and Survivorship; 2015 Nov 9-12; Fort Lauderdale, FL. Philadelphia (PA): AACR; Cancer Res 2016;76(5 Suppl):Abstract nr B03.

This study aims to identify novel therapeutic targets for nonseminomatous pediatric germ cell tumors (GCTs). GCTs are the most common cancer in young men, and affect both children and adolescents. They are histologically classified into two types: seminomatous GCTs (SGCTs), which are undifferentiated, and non-seminomatous GCTs (NSGCTs), which exhibit differentiation. Although cisplatin treatment is effective for many types of GCTs, cisplatin resistance, which is especially common in NSGCTs, confers poor prognosis for affected patients. However, because the signaling pathways and genes responsible for the development of different types of GCTs are not well-understood, few targeted therapies exist for GCTs, and no specific therapies exist for NSGCTs. Therefore, novel therapies to specifically target NSGCTs are needed. To determine a targetable pathway that is activated in GCTs, we used quantitative RT-PCR to measure the expression of growth factor receptors in pediatric GCTs, immunohistochemistry (IHC) on a panel of clinically annotated germ cell tumors, and Western blot as well as cell viability assays on NSGCT cell lines (NCCIT and NTERA-2) to determine the effect of inhibition of two signaling pathways on cell viability. Our RT-PCR results showed that multiple members of the EGF and FGF receptor families are expressed at higher levels in NSGCTs than SGCTs. In addition, we found that EGF and FGF2 stimulate Ras-MAPK as well as PI3K/mTOR signaling in NSGCT cell lines. Based on IHC staining of phosphorylated ERK1/2, mTOR, and S6 ribosomal protein, we showed that both the Ras-MAPK and PI3K-mTOR pathways are activated at higher levels in NSGCTs than SGCTs. The results suggested that inhibiting EGFR as well as mTORC1 may be effective in impairing the growth and survival of NSGCT cell lines. To test this hypothesis, we examined the effects of two small molecule inhibitors of EGFR and mTOR signaling, erlotinib and rapamycin, respectively, on the survival of NCCIT and NTERA-2 cell lines. We verified by Western blot that erlotinib inhibits components of the Ras-MAPK pathway in NSGCT cell lines, while rapamycin inhibits components of the PI3K-mTOR pathway. Cell survival experiments showed that while treatment with rapamycin or erlotinib alone decreased cell viability, sufficient reduction of survival could only be achieved with high concentrations that are not clinically feasible. However, a combination treatment of erlotinib and rapamycin synergistically inhibited the growth of the two NSGCT cell lines at clinically achievable concentrations. Our findings showed that NSGCTs are dependent on EGFR and mTOR signaling in vitro, and suggest that targeting these signaling pathways may be a promising therapy to specifically target chemoresistant NSGCTs. Citation Format: Albert Budhipramono, Dinesh Rakheja, Kenneth S. Chen, Nicholas Fustino, Abhay Shukla, Jonathan Wickiser, Theodore Laetsch, James F. Amatruda. EGFR and mTORC1 are novel therapeutic targets in nonseminomatous germ cell tumors. [abstract]. In: Proceedings of the AACR Special Conference on Advances in Pediatric Cancer Research: From Mechanisms and Models to Treatment and Survivorship; 2015 Nov 9-12; Fort Lauderdale, FL. Philadelphia (PA): AACR; Cancer Res 2016;76(5 Suppl):Abstract nr B03.

TPS2638 Background: Germ cell tumors (GCTs) affect children and young adults, with testicular germ cell tumor the most common cancer in young men. While platinum-based treatment has been successful for many GCTs, patients whose tumors are platinum-refractory have a poor prognosis. We have previously shown that non-seminomatous germ cell tumor cell lines are dependent on EGFR and mTOR signaling for survival and that the combined inhibition of these two targets in the same pathway results in >1000-fold sensitization to drug in vitro (Rakheja, AACR Peds Cancer 2013). The combination of the EGFR inhibitor erlotinib and the mTOR inhibitor sirolimus has been studied in other tumors, but never in germ cell tumors. Previous studies have not included assessment of pharmacodynamic inhibition of the targets in patients. Recently, flow cytometry based methods for detection of intracellular phosphorylated forms of S6 (downstream of mTOR), and ERK and AKT (downstream of EFGR) in peripheral blood mononuclear cells (PBMC) have been developed. This is the first pediatric trial to determine target inhibition in patients treated with the combination of EGFR and mTOR inhibitors. Methods: Eligible patients are those aged 1-50 years with relapsed or refractory germ cell tumors who have failed at least two prior platinum containing regimens. Patients with CNS disease are excluded. Patients receive daily sirolimus adjusted to a trough of 10-15 ng/mL and daily erlotinib at a starting dose of 120 mg/m2. As the development of rash may be a biomarker of response to erlotinib, patients who don’t develop grade II or worse rash during cycle 1 receive 150mg/m2 for subsequent cycles. Pharmacokinetics and target inhibition in PBMCs using phospho-flow cytometry are measured during cycles 1 and 2 and correlated with response. The primary endpoint is progression free response (PFR) after 16 weeks of therapy. Using a Simon 2-stage design, 11 patients will be enrolled in the first cohort and an additional 16 patients in the second if 2 or more of the initial 11 patients have PFR. This regimen will be considered beneficial if greater than or equal to 6 of the 27 evaluable patients have PFR (response rate of 20%). This study began enrollment in January 2014 and no results are yet available. Clinical trial information: NCT01962896.

PURPOSE:The COG (Children's Oncology Group) currently recommends surveillance for all children and adolescents with clinical stage I testicular germ cell tumors. However, up to 30% of adults with clinical stage I testicular germ cell tumors harbor occult metastatic disease. In adults with clinical stage I nonseminoma some groups advocate a risk stratified approach. Occult metastases were noted in 50% of patients with features such as lymphovascular invasion or embryonal carcinoma predominance in the orchiectomy. However, to our knowledge there are no data on the impact of high risk features in such pubertal children and postpubertal adolescents.MATERIALS AND METHODS:We reviewed an institutional testis cancer database for pubertal children and postpubertal adolescents younger than 21 years. We tested the hypothesis that lymphovascular invasion, or 40% or greater embryonal carcinoma in the orchiectomy specimen, would increase the risk of occult metastases, ie relapse during surveillance or positive nodes on retroperitoneal lymph node dissection.RESULTS:We identified 23 patients with a median age of 18.6 years (range 7.1 to 20.9) at diagnosis. Of these patients 14 (60.9%) were on surveillance, 9 (39.1%) underwent primary retroperitoneal lymph node dissection and none received initial chemotherapy. Seven patients (30.4%) had occult metastatic disease. High risk pathological features were found in the orchiectomy specimen in 12 patients (52.2%), including all 12 (52.2%) with 40% or greater embryonal carcinoma and 3 (13.0%) with lymphovascular invasion. Seven patients (58.3%) with high risk features had occult metastatic disease vs none (0%) without high risk features (log rank p = 0.031).CONCLUSIONS:Approximately half of pubertal children and postpubertal adolescents with high risk clinical stage I testicular germ cell tumors harbor occult metastatic disease. These results may be useful when discussing prognosis and treatment with patients and families.

BackgroundTesticular germ cell tumors (T-GCTs) occur from infancy to adulthood, and are the most common solid tumor in adolescent and young adult males. Traditionally, pediatric T-GCTs were perceived as more indolent than adult T-GCTs. However, there are few studies comparing these groups and none that specifically evaluate adolescents.MethodsAn institutional database of T-GCT patients was reviewed and patients were categorized into Pediatric, aged 0-12 years, Adolescent, aged 13-19 years, and Adult, older than 20 years, cohorts. Demographics, tumor characteristics, disease stage, treatment, event-free survival (EFS), and overall survival (OS) were compared between groups.ResultsOverall, 413 patients (20 pediatric, 39 adolescent, 354 adult) met study criteria and were followed for a median of 2.0 years (0.1-23.6). Adolescents presented with more advanced stage than children (P=0.018) or adults (P=0.008). There was a higher rate of events in Adolescents (13, 33.3%) than in Adults (61, 17.2%) or Children (2, 10.0%). Three-year EFS was 87.2% in the Pediatric group, 59.9% in Adolescents and 80.0% in Adults (P=0.011). In a multivariate analysis, controlling for stage, IGCCCG risk, and histology, the hazard ratio (HR) for an event was: 1 (Reference) for Adults, HR=0.82 (95% CI 0.19-3.46; P=0.33) for the Pediatric group, and HR=2.22 (95% CI 1.21-4.07; P=0.01) for Adolescents. Five-year OS was 100% in the Pediatric group, 84.8% in Adolescents, and 92.8% in Adults (P=0.388).ConclusionLower EFS in adolescent T-GCT patients was observed than in either children or adults. Elucidating factors associated with inferior outcomes in adolescents is an important focus of future research. Pediatr Blood Cancer 2014;61:446-451. (c) 2013 Wiley Periodicals, Inc.

Wilms tumour is the most common childhood kidney cancer. Here we report the whole-exome sequencing of 44 Wilms tumours, identifying missense mutations in the microRNA (miRNA)-processing enzymes DROSHA and DICER1, and novel mutations in MYCN, SMARCA4 and ARID1A. Examination of tumour miRNA expression, in vitro processing assays and genomic editing in human cells demonstrates that DICER1 and DROSHA mutations influence miRNA processing through distinct mechanisms. DICER1 RNase IIIB mutations preferentially impair processing of miRNAs deriving from the 5'-arm of pre-miRNA hairpins, while DROSHA RNase IIIB mutations globally inhibit miRNA biogenesis through a dominant-negative mechanism. Both DROSHA and DICER1 mutations impair expression of tumour-suppressing miRNAs, including the let-7 family, important regulators of MYCN, LIN28 and other Wilms tumour oncogenes. These results provide new insights into the mechanisms through which mutations in miRNA biogenesis components reprogramme miRNA expression in human cancer and suggest that these defects define a distinct subclass of Wilms tumours.

PURPOSE:To evaluate the efficacy of needle biopsy for diagnosing Wilms tumor (WT) before chemotherapy.MATERIALS AND METHODS:We reviewed our institutional experience with Tru-Cut biopsy of pediatric renal masses in patients who subsequently underwent nephrectomy. We compared biopsy pathology with nephrectomy specimens to determine if biopsy accurately predicted final pathology.RESULTS:Seven children underwent Tru-Cut renal mass biopsy followed by surgical resection. In 4 patients, the final biopsy pathology was definitively read as WT and in 3 subjects, the pathology was read as WT versus hyperplastic nephrogenic rest. In all 7 patients, the nephrectomy pathology confirmed a diagnosis of WT. There were no complications after biopsy, and no patients have had local or regional recurrence.CONCLUSION:In our experience, pre-therapy Tru-Cut biopsy safely provides an adequate specimen for pathologic review in diagnosing WT.

PURPOSE:Nephron sparing surgery is accepted as standard of care for children with bilateral Wilms tumor or Wilms tumor in a solitary kidney and some study protocols allow nephron sparing surgery in select cases of unilateral Wilms tumor. With the increasing use of nephron sparing surgery in Wilms tumor, we reviewed pathological features from Wilms tumor radical nephrectomy specimens to determine the potential efficacy of a nephron sparing approach.MATERIALS AND METHODS:Medical records of children undergoing pre-chemotherapy radical nephrectomy for unilateral Wilms tumor at our institution were reviewed. Ideal candidates for nephron sparing surgery were defined as those having a unifocal mass outside the renal hilum, sparing a third or more of the kidney, favorable histology, no signs of renal sinus or segmental vascular invasion, no metastatic lymph nodes or gross regional disease, and a distinct interface on pathological review between tumor and remaining parenchyma.RESULTS:A total of 78 children at a median age of 3.2 years (range 0.3 to 16.2) underwent pre-chemotherapy radical nephrectomy for unilateral Wilms tumor. Median tumor diameter was 11 cm (range 2.5 to 22). Of these children 36 (46.2%) had tumors sparing a third or more of the kidney and 70 (89.7%) had unifocal tumors. There were 73 specimens (94.6%) that showed favorable histology, and 56 (71.8%) of the specimens had a distinct border between tumor and remaining parenchyma. In total, 19 (24.4%) of the patients reviewed met all of our strict pathological criteria as ideal partial nephrectomy candidates.CONCLUSIONS:In a post hoc analysis using strict pathological criteria and accepted surgical oncologic principles, as many as 1 in 4 children undergoing pre-chemotherapy surgery for nonmetastatic, unilateral Wilms tumor have post-resection pathological tumor characteristics favorable for nephron sparing surgery.

Radical nephrectomy (RN) is the recommended surgical management as part of multi‐modality therapy for unilateral Wilms tumor (UWT). Based on recent data demonstrating that renal preserving surgery decreases the likelihood of chronic renal disease and associated co‐morbidities, we analyzed oncologic outcomes of patients after partial nephrectomy (PN) for UWT.