Long-term outcomes for infants with very low risk Wilms tumor treated with surgery alone in National Wilms Tumor Study-5

Current surgical approaches to pediatric renal tumors

Pediatric renal tumors are among the most common pediatric solid malignancies. Surgical resection is a key component in the multidisciplinary therapy for children with kidney tumors. Therefore, it is imperative that surgeons caring for children with renal tumors fully understand the current standards of care in order to provide appropriate surgical expertise within this multimodal framework. Fortunately, the last 60 years of international, multidisciplinary pediatric cancer cooperative group studies have enabled high rates of cure for these patients. This review will highlight the international surgical approaches to pediatric patients with kidney cancer to help surgeons understand the key differences and similarities between the European (International Society of Pediatric Oncology) and North American (Children's Oncology Group) recommendations.

Nephroblastoma in Older Adult: Case Report and Review of Literature

Introduction

Nephroblastoma, or Wilms' tumor, is a malignant renal neoplasm commonly found in children, is extremely rare in adults representing only 0.5% of all renal neoplasms. Adult Wilms tumor is rare, to our knowledge fewer than 300 cases have been reported in the English literature to date. However, in older adults after 60 years of age, only less than 45 cases have been reported. For this reason, treatment guidelines in adults still are lacking. Prognosis in nephroblastoma for adult patients is found to be worse than in children.

Case Presentation

We report the case of a 65-year-old female with lumbar fossa mass, flank pain and hematuria, and pathologic diagnosis of Wilms tumor. We performed nephrectomy. No adjuvant treatment was given. Our patient remains asymptomatic and without evidence of recurrence 12 months after the surgery.

Conclusion

Nephroblastoma in the elderly presents different clinical behavior and prognosis compared to nephroblastoma in children.

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

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSION

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

Stage I epithelial or stromal type Wilms tumors are low risk tumors: An analysis of patients treated on the SIOP-WT-2001 protocol in the UK-CCLG and GPOH studies (2001-2020)

BACKGROUND

Patients treated with preoperative chemotherapy with stage I intermediate-risk Wilms tumor (IR-WT) represent the largest group of patients with Wilms tumor (WT), and they have excellent outcomes.

METHODS

The authors performed a retrospective analysis of patients with stage I epithelial (ET-WT) or stromal type WT (ST-WT) treated pre- and postoperatively according to the International Society of Paediatric Oncology-WT-2001 protocol in the UK Children's Cancer and Leukaemia Group and Gesellschaft für Pädiatrische Onkologie und Hämatologie groups' participation in the relevant WT trials and studies (2001-2020).

RESULTS

There were 880 patients with stage I IR-WT, including 124 with ET-WT, 156 with ST-WT, and 600 with other IR-WT (oIR-WT). Patients with stage I ET-WT or ST-WT were significantly younger than patients with oIR-WT, represented a large proportion of stage I WTs in their groups, and tumors showed poor histologic response to preoperative chemotherapy. The 5-year event-free survival (EFS) estimates for patients with stage I ET-WT (96.8% ± 1.8 SE) or ST-WT (96.8% ± 1.6 SE) were significantly better than for patients with oIR-WT (90.3% ± 1.3 SE) (p = .014 and p = .009, respectively). A multivariate analysis showed that histologic type (ET-WT or ST-WT) remained a significant factor for EFS when adjusted for age and gender (p = .032 and p = .022, respectively). In both groups, relapses occurred in 3.2% of patients, and the overall survival was 99.2%.

CONCLUSIONS

The results suggest that stage I ET-WT or ST-WT could be regarded as low-risk WT, for which omission of postoperative chemotherapy should be considered.

PLAIN LANGUAGE SUMMARY

Patients with pretreated intermediate-risk Wilms tumor (WT) represent the largest group of patients with WT. This study reports the outcomes of patients with stage I epithelial type (ET-WT) or stromal type WT (ST-WT). These patients were significantly younger and had a larger proportion of stage I cases than patients with other intermediate-risk WT (oIR-WT). The event-free survival for patients with stage I ET-WT and ST-WT was significantly better than for patients with oIR-WT. Rare relapses were curable resulting in 99.2% overall survival.

Evidence-based surgical guidelines for treating children with Wilms tumor in low-resource settings

BACKGROUND

Survival of Wilms tumor (WT) is > 90% in high-resource settings but < 30% in low-resource settings. Adapting a standardized surgical approach to WT is challenging in low-resource settings, but a local control strategy is crucial to improving outcomes.

OBJECTIVE

Provide resource-sensitive recommendations for the surgical management of WT.

METHODS

We performed a systematic review of PubMed and EMBASE through July 7, 2020, and used the GRADE approach to assess evidence and recommendations.

RECOMMENDATIONS

Initiation of treatment should be expedited, and surgery should be done in a high-volume setting. Cross-sectional imaging should be done to optimize preoperative planning. For patients with typical clinical features of WT, biopsy should not be done before chemotherapy, and neoadjuvant chemotherapy should precede surgical resection. Also, resection should include a large transperitoneal laparotomy, adequate lymph node sampling, and documentation of staging findings. For WT with tumor thrombus in the inferior vena cava, neoadjuvant chemotherapy should be given before en bloc resection of the tumor and thrombus and evaluation for viable tumor thrombus. For those with bilateral WT, neoadjuvant chemotherapy should be given for 6-12 weeks. Neither routine use of complex hilar control techniques during nephron-sparing surgery nor nephron-sparing resection for unilateral WT with a normal contralateral kidney is recommended. When indicated, postoperative radiotherapy should be administered within 14 days of surgery. Post-chemotherapy pulmonary oligometastasis should be resected when feasible, if local protocols allow omission of whole-lung irradiation in patients with nonanaplastic histology stage IV WT with pulmonary metastasis without evidence of extrapulmonary metastasis.

CONCLUSION

We provide evidence-based recommendations for the surgical management of WT, considering the benefits/risks associated with limited-resource settings.

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.

Impact of the First Generation of Children's Oncology Group Clinical Trials on Clinical Practice for Wilms Tumor

Refinements in surgery, radiation therapy, and chemotherapy since the mid-20th century have resulted in a survival rate exceeding 90% for patients with Wilms tumor (WT). Although this figure is remarkable, a significant proportion of patients continue to have event-free survival (EFS) estimates of <75%, and nearly 25% of survivors experience severe chronic medical conditions. The first-generation Children's Oncology Group (COG) renal tumor trials (AREN '0'), which opened to enrollment in 2006, focused on augmenting treatment regimens for WT subgroups with predicted EFS <75% to 80%, including those with the adverse prognostic marker of combined loss of heterozygosity (LOH) at chromosomes 1p/16q, pulmonary metastasis with incomplete lung nodule response after 6 weeks of chemotherapy, bilateral disease, and anaplastic histology. Conversely, therapy was reduced for patient subgroups with good outcomes and potential for long-term toxicity, such as those with lung metastasis with complete lung nodule response after 6 weeks of chemotherapy. This article summarizes the key findings of the first-generation COG renal tumor studies and their implications for clinical practice.

Stable Isotope Abundance and Fractionation in Human Diseases

The natural abundance of heavy stable isotopes (¹³C, ¹⁵N, ¹⁸O, etc.) is now of considerable importance in many research fields, including human physiology. In fact, it varies between tissues and metabolites due to isotope effects in biological processes, that is, isotope discriminations between heavy and light isotopic forms during enzyme or transporter activity. The metabolic deregulation associated with many diseases leads to alterations in metabolic fluxes, resulting in changes in isotope abundance that can be identified easily with current isotope ratio technologies. In this review, we summarize the current knowledge on changes in natural isotope composition in samples (including various tissues, hair, plasma, saliva) found in patients compared to controls, caused by human diseases. We discuss the metabolic origin of such isotope fractionations and highlight the potential of using isotopes at natural abundance for medical diagnosis and/or prognostic.

New approaches to risk stratification for Wilms tumor

PURPOSE OF REVIEW

The treatment of Wilms tumor is one of the great achievements in the field of oncology. One of the key success factors has been improved risk stratification, enabling augmentation or reduction of therapy depending on a patient's risk of relapse. This article highlights the evolution of clinical and biological prognostic markers that have been applied in the treatment of Wilms tumor.

RECENT FINDINGS

Historically, tumor stage and histology were the sole determinants of Wilms tumor treatment. Recent clinical trials conducted by the Children's Oncology Group (COG) and the International Society of Pediatric Oncology (SIOP) Renal Tumor Study Group have expanded the menu of prognostic factors to include histologic and volumetric response to therapy and tumor-specific loss of heterozygosity (LOH) at chromosomes 1p and 16q. Augmentation of therapy has been able to overcome the adverse risk factors. An emerging prognostic marker is chromosome 1q gain, will be incorporated into future clinical trials.

SUMMARY

The application of new clinical and biological prognostic factors has created unprecedented ability to tailor therapy for Wilms tumor, accompanied with improved outcomes. Current and future trials will continue to enhance precision medicine for Wilms tumor.

Long-term Outcome in Children with Wilms’ Tumor; Experience of a Single Center for Two Decades

Background: Wilms’ tumor (nephroblastoma) is the major renal cancer in children. Objectives: The aim of this study was to assess the individuality of Wilms’ tumor and the consequences of management attained in our referral subspecialty center. Methods: In this study, we composed the data of children with Wilms’ tumor in 2 decades; 55 cases between 1992 and 2002 and 49 patients between 2006 and 2016 were diagnosed with Wilms’ tumor. Demographic characters, a form of presentation, tumor stage, related underlying disease, histopathology consequences, type of management, and the survival rates were assessed. Results: In the first decade, 24 patients were females and 31 were males (M/F = 1.2); in the other groups, 30 were females and 19 were males (M/F = 0.61). The mean age was 45.2 months at the time of diagnosis for the first group and the mean age was 36 months for the other group. In the first decade, the surgical stage after the operation was as follows: stage I (32.7%), stage II (16.36%), stage III (38.1%), stage IV (9%), and stage V (1.8%) who did not operate. In second decade, 49 patients were as follows: stage I (14.3%), stage II (40.8%), stage III (24.5%), stage IV (10.2%), and stage V (10.2%). In 54.5% of the first group, histology was favorable, and in 43.6% of the first group, histology was unfavorable; in the second group, 95.4% were the favorable type. The patients were managed based on protocols of the National Wilms’ Tumor Study. In the first decade, relapse-free was 71% and 4-year survival rates were estimated at 86%, and in the second decade, pulmonary metastasis was observed at 28.6%, liver metastasis in 2.3%, recurrence in 5%, and 4-year survival rates were estimated at 90%. Conclusions: This study demonstrated development in the management of children with Wilms’ tumor in recent 20 years, with comparable relapse-free and survival rates to the National Wilms’ Tumor study. But with more adjustment in treatment protocols, the superior outcome will be attainable.

Surgical Management of Wilms Tumor (Nephroblastoma) and Renal Cell Carcinoma in Children and Young Adults

This article reviews the epidemiology, pathophysiology, clinical presentation, and multimodality management of Wilms tumors and renal cell carcinoma in pediatric and young adults. Key renal Société Internationale d'Oncologie Pédiatrique and Children Oncology Group studies are presented. The article reviews the common staging systems and risk-adapted treatment strategies with particular attention to the surgical management.

Minimally invasive surgery for pediatric renal tumors: A systematic review by the APSA Cancer Committee

Minimally invasive nephrectomy is performed routinely for adult renal tumors and for many benign pediatric conditions. Although open radical nephroureterectomy remains the standard of care for Wilms tumor and most pediatric renal malignancies, there are an increasing number of reports of minimally invasive surgery (MIS) for those operations as well. The APSA Cancer Committee performed a systematic review to better understand the risks and benefits of MIS in pediatric patients with renal tumors.

METHODS

The search focused on MIS for renal tumors in children and followed the Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) checklist. The initial database search identified 491 published articles, and after progressive review of abstracts and full-length articles, 19 were included in this review.

RESULTS

There were two direct comparison studies where open surgery and MIS were compared. The remaining studies reported only on minimally invasive nephrectomy. Across all studies, there were a total of 151 patients, 126 of which had Wilms tumor and 10 patients had RCC. 104 patients had MIS, with 47 patients having open surgery. In the two studies in which open surgery and MIS were directly compared, more lymph nodes were harvested during open surgery (median = 2 (MIS) vs 5 (open); mean = 2.47 (MIS) vs 3.8 (open)). Many noncomparison studies reported the harvest of 2 of fewer lymph nodes for Wilms tumor. Several MIS patients were also noted to have intraoperative spill or positive margins. Survival between groups was similar.

CONCLUSIONS

There is a lack of evidence to support MIS for pediatric renal tumors. This review demonstrates that lymph node harvest has been inadequate for MIS pediatric nephrectomy and there appears to be an increased risk for intraoperative spill. Survival data are similar between groups, but follow-up times were inconsistent and patient selection was clearly biased, with only small tumors being selected for MIS.

TYPE OF STUDY

Review article.

LEVEL OF EVIDENCE

III.

Outcome analysis of stage I epithelial-predominant favorable-histology Wilms tumors: A report from Children's Oncology Group study AREN03B2

BACKGROUND

Stage I epithelial-predominant favorable-histology Wilms tumors (EFHWTs) have long been suspected to have an excellent outcome. This study investigates the clinical and pathologic features of patients with stage I EFHWTs to better evaluate the potential for a reduction of chemotherapy and its associated toxicity.

METHODS

All patients registered in the Children's Oncology Group (COG) AREN03B2 study between 2006 and 2017 with stage I EFHWTs were identified. EFHWTs were defined as tumors with at least 66% epithelial differentiation, regardless of the degree of differentiation. Clinical information was abstracted from COG records. Event-free survival (EFS) and overall survival (OS) were calculated and compared between groups based on age and therapy.

RESULTS

The 4-year EFS rate was 96.2% (95% confidence interval, 92%-100%), and the OS rate was 100%; EFS and OS did not statistically significantly differ with the age at diagnosis (<48 vs ≥48 months; P = .37) or treatment (EE4A vs observation only; P = .55). Six events were reported. Three patients developed contralateral tumors and did not otherwise relapse; none of these had nephrogenic rests or a recognized predisposition syndrome. Three patients developed metastatic recurrence; all 3 had received EE4A as their primary therapy after nephrectomy.

CONCLUSIONS

These findings demonstrate an excellent outcome for stage I EFHWTs with >95% EFS and OS. These data support the utility of investigating the treatment of stage I EFHWTs with observation alone after nephrectomy.

The impact of cooperative group studies on childhood cancer: Improving outcomes and quality and international collaboration

The advances in pediatric cancer far exceed those achieved in adults. The success in improving survival and minimizing late effects has been due to several reasons but work of the pediatric cancer cooperative groups is a primary. These cooperative groups are multidisciplinary with medical oncologists, pathologists, radiologists, surgeons, radiation oncologists, scientists and most importantly the patients and families. Studies have expanded from regional to national and now international studies which continue to target problems pertinent to improving the outcome for children with cancer. In this article we review the history of the cooperative groups, a selection of seminal studies pertaining to solid tumors, future challenges and collaborations.

Prognostic significance of age in 5631 patients with Wilms tumour prospectively registered in International Society of Paediatric Oncology (SIOP) 93-01 and 2001

BACKGROUND

To enhance risk stratification for Wilms tumour (WT) in a pre-operative chemotherapy setting, we explored the prognostic significance and optimal age cutoffs in patients treated according to International Society of Paediatric Oncology Renal Tumour Study Group (SIOP-RTSG) protocols.

METHODS

Patients(6 months-18 years) with unilateral WT were selected from prospective SIOP 93-01 and 2001 studies(1993-2016). Martingale residual analysis was used to explore optimal age cutoffs. Outcome according to age was analyzed by uni- and multivariable analysis, adjusted for sex, biopsy(yes/no), stage, histology and tumour volume at surgery.

RESULTS

5631 patients were included; median age was 3.4 years(IQR: 2-5.1). Estimated 5-year event-free survival (EFS) and overall survival (OS) were 85%(95%CI 83.5-85.5) and 93%(95%CI 92.0-93.4). Martingale residual plots detected no optimal age cutoffs. Multivariable analysis showed lower EFS with increasing age(linear trend P<0.001). Using previously described age categories, EFS was lower for patients aged 2-4(HR 1.34, P = 0.02), 4-10(HR 1.83, P<0.0001) and 10-18 years(HR 1.74, P = 0.01) as compared to patients aged 6 months-2 years. OS was lower for patients 4-10 years(HR 1.67, P = 0.01) and 10-18 years(HR 1.87, P = 0.04), but not for 2-4 years(HR 1.29, P = 0.23). Higher stage, histological risk group and tumour volume were independent adverse prognostic factors.

CONCLUSION

Although optimal age cutoffs could not be identified, we demonstrated the prognostic significance of age as well as previously described cutoffs for EFS (2 and 4 years) and OS (4 years) in children with WT treated with pre-operative chemotherapy. These findings encourage the consideration of age in the design of future SIOP-RTSG protocols.

Pharmacotherapeutic Management of Wilms Tumor: An Update

Although differences exist in treatment and risk-stratification strategies for children with Wilms tumor (WT) between the European [International Society of Paediatric Oncology (SIOP)] and American [Children's Oncology Group (COG)] study groups, outcomes are very similar, with an overall survival of > 85%. Future strategies aim to de-intensify treatment and reduce toxicity for children with a low risk of relapse and intensify treatment for children with high-risk disease. For metastatic WT, response of lung nodules to chemotherapy is used as a marker to modify treatment intensity. For recurrent WT, a unified approach based on the use of agents that were not used for primary therapy is being introduced. Irinotecan is being explored as a new strategy in both metastatic and relapsed WT. Introduction of biology-driven approaches to risk stratification and new drug treatments has been slower in WT than in some other childhood cancers. While several new biological pathways have been identified recently in WT, their individual rarity has hampered their translation into clinical utility. Identification of robust prognostic factors requires extensive international collaborative studies because of the low proportion who relapse or die. Molecular profiling studies are in progress that should ultimately improve both risk classification and signposting to more targeted therapies for the small group for whom current therapies fail. Accrual of patients with WT to early-phase trials has been low, and the efficacy of these new agents has so far been very disappointing. Better in vitro model systems to test mechanistic dependence are needed so available new agents can be more rationally prioritized for recruitment of children with WT to early-phase trials.

Biological Drivers of Wilms Tumor Prognosis and Treatment

Prior to the 1950s, survival from Wilms tumor (WT) was less than 10%. Today, a child diagnosed with WT has a greater than 90% chance of survival. These gains in survival rates from WT are attributed largely to improvements in multimodal therapy: Enhanced surgical techniques leading to decreased operative mortality, optimization of more effective chemotherapy regimens (specifically, dactinomycin and vincristine), and inclusion of radiation therapy in treatment protocols. More recent improvements in survival, however, can be attributed to a growing understanding of the molecular landscape of Wilms tumor. Particularly, identification of biologic markers portending poor prognosis has facilitated risk stratification to tailor therapy that achieves the best possible outcome with the least possible toxicity. The aim of this review is to (1) outline the specific biologic markers that have been associated with prognosis in WT and (2) provide an overview of the current use of biologic and other factors to stratify risk and assign treatment accordingly.

Outcome of renal tumors registered in Japan Wilms Tumor Study-2 (JWiTS-2): A report from the Japan Children's Cancer Group (JCCG)

BACKGROUND

Japan Wilms Tumor Study-2 (JWiTS-2) mandated central pathology review for all case registrations. The study aimed to compare the outcomes of patients with unilateral Wilms tumor enrolled on the JWiTS-1 and JWiTS-2 trials.

PROCEDURE

The JWiTS-2 trial (2006-2014), a prospective, single-arm study, required compulsory submission of histologic slides to central pathology, while in the JWiTS-1 trial, such submission was not compulsory. Relapse-free survival (RFS) and overall survival (OS) versus cases in the JWiTS-1 trial (1996-2005) were statistically evaluated.

RESULTS

Of 277 enrolled patients with primary renal tumors diagnosed by the central pathology review system, 225 patients with unilateral renal tumors were followed up over 9 years. The RFS and OS of Wilms tumor (n = 178) were 90.4% (P = 0.0003) and 96.8% (P = 0.054), respectively, as compared to 74.9% and 89.4% in JWiTS-1. RFS rates of stages I-III Wilms tumor in JWiTS-2 were more than 90%, although the outcome of stage IV Wilms tumor was significantly poorer (RFS: 66.2%) (P = 0.0094). RFS and OS of clear cell sarcoma of the kidney (CCSK; n = 31) were 82.4% (P = 0.30) and 91.3% (P = 0.42), respectively, as compared to 68.8% and 81.3% in JWiTS-1, and those of rhabdoid tumor of the kidney (RTK; n = 16) were 18.8% (P = 0.88) and 25.0% (P = 0.80), respectively, as compared to 23.5% and 23.5% in JWiTS-1.

CONCLUSIONS

RFS and OS for stages I-III Wilms tumor were improved in JWiTS-2 compared to JWiTS-1, whereas outcomes for stage IV Wilms tumor, CCSK, and RTK did not improve.

The first investigation of Wilms' tumour atomic structure-nitrogen and carbon isotopic composition as a novel biomarker for the most individual approach in cancer disease

The paper describes a novel approach to investigating Wilms' tumour (nephroblastoma) biology at the atomic level. Isotope Ratio Mass Spectrometry (IRMS) was used to directly assess the isotope ratios of nitrogen and carbon in 84 Wilms' tumour tissue samples from 28 cases representing the histological spectrum of nephroblastoma. Marked differences in nitrogen and carbon isotope ratios were found between nephroblastoma histological types and along the course of cancer disease, with a breakout in isotope ratio of the examined elements in tumour tissue found between stages 2 and 3. Different isotopic compositions with regard to nitrogen and carbon content were observed in blastemal Wilms' tumour, with and without focal anaplasia, and in poorly- and well-differentiated epithelial nephroblastoma. This first assessment of nitrogen and carbon isotope ratio reveals the previously unknown part of Wilms' tumour biology and represents a potential novel biomarker, allowing for a highly individual approach to treating cancer. Furthermore, this method of estimating isotopic composition appears to be the most sensitive tool yet for cancer tissue evaluation, and a valuable complement to established cancer study methods with prospective clinical impact.

Clinical Outcome and Biological Predictors of Relapse After Nephrectomy Only for Very Low-risk Wilms Tumor: A Report From Children's Oncology Group AREN0532

OBJECTIVE

To determine if observation alone after nephrectomy in very low-risk Wilms tumor (defined as stage I favorable histology Wilms tumors with nephrectomy weight <550g and age at diagnosis <2 years) results in satisfactory event-free survival and overall survival, and to correlate relapse with biomarkers.

PATIENTS AND METHODS

The AREN0532 study enrolled patients with very low-risk Wilms tumor confirmed by central review of pathology, diagnostic imaging, and surgical reports. After nephrectomy, patients were followed without adjuvant chemotherapy. Evaluable tumors were analyzed for WT1mutation, 1p and 16q copy loss, 1q copy gain, and 11p15 imprinting. The study was powered to detect a reduction in 4-year EFS from 87% to 75% and overall survival from 95% to 88%.

RESULTS

A total of 116 eligible patients enrolled with a median follow up of 80 months (range: 5-97 months). Twelve patients relapsed. Estimated 4-year event-free survival was 89.7% (95% confidence interval 84.1-95.2%) and overall survival was 100%. First sites of relapse were lung (n = 5), tumor bed (n = 4), and abdomen (n = 2), with one metachronous tumor in the contralateral kidney (n = 1) at a median time of 4.3 months for those who relapsed (range 2.3-44 months). The presence of intralobar (P = 0.46) or perilobar rests (P = 1.0) were not associated with relapse (P = 0.16). 1q gain, 1p and 16q loss, and WT1 mutation status were not associated with relapse. 11p15 methylation status was associated relapse (20% relapse with loss of heterozygosity, 25% with loss of imprinting, and 3.3% relapse with retention of the normal imprinting (P = 0.011)).

CONCLUSIONS

Most patients meeting very low-risk criteria can be safely managed by nephrectomy alone with resultant reduced exposure to chemotherapy. Expansion of an observation alone strategy for low-risk Wilms tumor incorporating both clinical features and biomarkers should be considered.

Renal Tumors in Children Younger Than 12 Months of Age: A 65-Year Single Institution Review

Wilms tumor (WT) is the most prevalent pediatric renal tumor and most commonly occurs between ages 1 and 5 years. Data are lacking on children younger than 12 months with renal tumors. The cancer registry at the authors' institution was queried to identify patients 12 months and younger with renal masses. Demographics, clinical presentation, histopathology, stage, and survival outcomes were reviewed. The most common presenting symptoms included an asymptomatic abdominal mass (73%) and hematuria (9%). Histopathology revealed WT in 73% of patients, mesoblastic nephroma in 20%. Of those infants younger than 1 month of age, mesoblastic nephroma was the most common histopathology (68%). The 5-year overall survival (OS) was 93%, and 5-year event-free survival (EFS) was 93% for the entire group. For patients with WT, 5-year OS was 88% and 5-year EFS was 83%. Outcomes for congenital mesoblastic nephroma were excellent with 5-year OS and EFS of 100%. Reasons for good prognosis may be multifactorial and may include frequent well child checks in the first year of life and favorable histology. Patients in this age group are more likely to be classified as very low risk and may be treated with surgical resection alone.

Wilms tumor: "State-of-the-art" update, 2016

Despite an impressive increase in survival rate over the past decades, there is still a need to improve the survival of specific subgroups of Wilms tumor (anaplastic, metastatic, and bilateral) and to decrease the late effects of treatment in terms of renal function and heart toxicity. We aim to explore new areas of improvement, from diagnosis to treatment: in the field of radiology the increased use of MRI and exploration of its diffusion-weighted imaging capabilities to predict WT histology at diagnosis and for preoperative assessment; in biology the emergence of new biomarkers that could be integrated into the decision-making process; and surgical techniques with more accurate indication of nephron-sparing surgery that is no longer reserved for bilateral WT and the minimally invasive approach. The long-term outcome of patients with WT should thus be a strong indicator of the improvement in adapting and personalizing the treatment to each individual.

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.

Renal tumor in developing countries: 142 cases from a single institution at Shanghai, China

BACKGROUND

The clinical management of children with renal tumors including Wilms' tumor, clear cell sarcoma, rhabdoid tumor and other renal tumors in our center was designed according to the National Wilms' Tumor Study Group protocols.

METHODS

A total of 142 consecutive patients who had been diagnosed as having renal tumors at Shanghai Children's Medical Center were reviewed retrospectively in the period of December 1998 and September 2012. Diagnosis and treatment were decided by a multidisciplinary team including oncologists, surgeons, pathologists and sub-specialized radiologists.

RESULTS

The median age of the patients at the time of diagnosis was 27 months. The tumor stages of the patients were as follows: stage I 24.6%, stage II 23.2%, stage III 32.3%, stage IV 14.1%, and stage V 5.6%. Favorable histology was diagnosed in 80.3%, anaplasia in 4.2%, clear cell sarcoma in 9.8%, rhabdoid tumor in 4.9%, and other renal tumors in 0.7% of the patients. The event-free and overall 5-year survival rates were 80% and 83%, respectively. Tumor relapse and progress was seen in 25 patients (17.6%). The median relapse time was 6 months (range: 2-37 months). Seven relapsing patients were retreated and four of them got second complete remission (three in stage II, one in stage I).

CONCLUSION

A multi-disciplinary team work model is feasible in developing countries, and the renal tumors protocols basically from developed countries are safe in developing countries.

Advances in Wilms Tumor Treatment and Biology: Progress Through International Collaboration

Clinical trials in Wilms tumor (WT) have resulted in overall survival rates of greater than 90%. This achievement is especially remarkable because improvements in disease-specific survival have occurred concurrently with a reduction of therapy for large patient subgroups. However, the outcomes for certain patient subgroups, including those with unfavorable histologic and molecular features, bilateral disease, and recurrent disease, remain well below the benchmark survival rate of 90%. Therapy for WT has been advanced in part by an increasingly complex risk-stratification system based on patient age; tumor stage, histology, and volume; response to chemotherapy; and loss of heterozygosity at chromosomes 1p and 16q. A consequence of this system has been the apportionment of patients into such small subgroups that only collaboration between large international WT study groups will support clinical trials that are sufficiently powered to answer challenging questions that move the field forward. This article gives an overview of the Children's Oncology Group and International Society of Pediatric Oncology approaches to WT and focuses on four subgroups (stage IV, initially inoperable, bilateral, and relapsed WT) for which international collaboration is pressing. In addition, biologic insights resulting from collaborative laboratory research are discussed. A coordinated expansion of international collaboration in both clinical trials and laboratory science will provide real opportunity to improve the treatment and outcomes for children with renal tumors on a global level.

Current surgical standards of care in Wilms tumor

BACKGROUND

Wilms tumor (WT) is the second most common abdominal tumor in children.

METHODS

This chapter discusses surgical considerations for the management of unilateral and bilateral WT.

RESULTS

Currently, survival exceeds 90%, owing to multicenter studies under the auspices of the Children's Oncology Group and Société Internationale d'Oncologie Pédiatrique. Surgical excision remains the mainstay of oncologic control and is also crucial for proper staging of disease in order to direct adjuvant therapy and limit treatment-related morbidity.

CONCLUSIONS

Careful attention must be paid to proper disease staging, upfront and adjuvant therapy, and surgical technique in order to optimize oncologic outcomes while minimizing short- and long-term morbidity.

Renal function in survivors of nonsyndromic Wilms tumor treated with unilateral radical nephrectomy

BACKGROUND

Partial nephrectomy is considered by some for children with unilateral Wilms tumor (UWT) to avoid the theoretical complication of renal insufficiency. In the current study, the authors evaluated the prevalence of hypertension and impaired renal function in long-term survivors of nonsyndromic UWT who were treated without nephrotoxic chemotherapy or ionizing radiation.

METHODS

Eligibility included age ≤15 years at the time of diagnosis of nonsyndromic UWT, treatment receipt before 2002, and maintenance of disease remission after unilateral nephrectomy without receipt of abdominal irradiation or nephrotoxic chemotherapy. Renal function was assessed by urinalysis and estimated glomerular filtration rate (eGFR). Patients receiving antihypertensive medication or those with blood pressure readings of >140/90 mm Hg were considered to be hypertensive.

RESULTS

A total of 75 patients with a median age at diagnosis of 3.2 years (range, 0.2-12.1 years) met eligibility criteria. The median length of follow-up was 19.6 years (range, 10.0-32.8 years). All but 1 patient had stage I/II disease. Sixty-eight patients (90.7%) patients had WT with favorable histology and 7 patients had anaplastic histology. Sixteen patients (21.3%) had an eGFR <90 mL/minute/1.73m(2), 2 of whom also had proteinuria (12.5%). No patient had an eGFR <60 mL/minute/1.73m(2). Five patients (6.7%) had hypertension, 3 of whom were receiving antihypertensive medications. At the time of last follow-up, no patient had developed end-stage renal disease.

CONCLUSIONS

Patients with UWT who were treated with unilateral radical nephrectomy without nephrotoxic chemotherapy or ionizing radiation appear to be at low risk of developing significant long-term renal dysfunction. For this patient population, the routine use of partial nephrectomy does not appear justified. However, monitoring and counseling are important for identifying the rare patient who develops subtle renal insufficiency and therefore might be at an increased risk of adverse cardiovascular sequelae.

Perioperative outcomes of primary renal tumour resections: comparison of in-hours to out-of-hours surgery

PURPOSE

Primary resection is typically performed for children with localised suspected Wilms tumours. Resource limitation may necessitate performing these operations nights and weekends. We hypothesise that outcomes will be worse in patients having nephrectomies out-of-hours (OOH) compared to those in-hours (IH).

METHODS

With IRB ethics approval, primary renal tumour resections performed on oncology patients from 1989-2011 were reviewed retrospectively. IH operations were defined as Monday-Friday 0745-1530 hours. Outcomes included major intraoperative complications, capsule rupture, and blood loss. Data were analysed using Fischer Exact and Mann-Whitney U tests.

RESULTS

There were 64 patients with renal tumours who underwent primary resection. Forty-five procedures were performed IH, and 19 OOH. Groups were similar in age, ASA status, tumour size and grade. In a comparison of major intraoperative complications, capsule rupture, and mean blood loss, differences were 2 vs. 26% (p = 0.007), 27 vs. 42% (p = 0.12), 178 vs. 244 ml (p = 0.15) for IH and OOH respectively. There was one perioperative mortality (OOH).

CONCLUSIONS

Primary renal tumour resections performed OOH were associated with an increase in major complications compared to those performed in standard hours. Avoidance of OOH operating where possible may reduce morbidity for children undergoing primary renal tumour resections.

Feasibility of using CT volume as a predictor of specimen weight in a subgroup of patients with low risk Wilms tumors registered on COG Study AREN03B2: implications for central venous catheter placement

OBJECTIVE

Patients with stage I Wilms tumor, age ≤ 2 years, tumor ≤ 550 g may not require therapy beyond nephrectomy. This study's aims were to determine: (1) if a linear relationship exists between tumor weight and computed tomography (CT) estimated volume; (2) describe the accuracy of a slope-intercept equation in estimating weight; and (3) determine the potential impact of weight estimation on port placement decisions.

MATERIALS AND METHODS

Tumor weight and port placement information were abstracted from 105 patients, age ≤ 2 years, with tumors ± 550 g, enrolled in COG AREN03B2. One radiologist estimated tumor size from CT scan. Prolate ellipse volume (PEV) was calculated, linear regression performed, slope-intercept equation calculated, equation estimated weight determined, and potential impact of the on port placement evaluated.

RESULTS

A strong relationship exists between PEV and weight (R(2) = 0.87). The slope-intercept equation for weight was: weight = 1.04(PEV) + 58.75. Overall median relative error for the equation was 0.9%, and -3% in tumors weighing 350-750 g. Fifty-five ports were placed, 29 in patients with tumor weight ≤ 550 g, and six not placed in patients with tumor weight > 550 g.

CONCLUSIONS

The relationship between PEV and weight produced a reliable weight prediction equation. Preoperative consideration of specimen weight may diminish the number of ports placed in this population.

Upper urinary tract anomalies and perinatal renal tumors

Congenital anomalies of the upper urinary tract are common and frequently diagnosed on prenatal ultrasound. In the absence of infection, these anomalies are often asymptomatic. This article reviews key features and long-term implications to assist in discussions with families. In contrast, a perinatal renal tumor is rare but extremely alarming. This update on the most common tumors and their treatment is useful in reassuring parents that most infants, after primary surgical resection, are cured without adjuvant therapies. To understand renal agenesis and other congenital renal malformations and their associated anomalies, a brief review of normal renal development is presented.

Innovations in the management of Wilms' tumor

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

Childhood renal tumor: a report from a Chinese Children's Cancer Group

Here we investigated the establishment of multicenter cooperative treatment groups in China, as well as radiotherapy compliance and effectiveness among children with renal tumors. Medical records were reviewed for 316 children with renal tumors diagnosed by a multicenter cooperative group from 14 hospitals in China from 1998 to 2012. Median patient age was 29.5 months (range, 2–173 months old), and male-to-female ratio was 1.4 : 1. After a median follow-up of 22 months (range, 1–177 months), five-year event-free survival rates were 72% overall; 76.1% for favorable histology (251 cases); 59% for unfavorable histology (27 cases); and 91%, 75%, 71%, 53%, and 48.5%, respectively for Stages I, II, III, IV, and V. Following standardized criteria, radiation therapy was indicated for 153 patients, among whom five-year event-free survival was 72.8% for the 95 who received radiation and 24% for the 58 patients who did not. Our results are reasonable but can be further improved and show the feasibility of a multicenter cooperative group model for childhood renal tumor treatment in China. Radiation therapy is important for stage III and IV patients but remains difficult to implement in some parts of China. Government management departments and medical professionals must pay attention to this situation. This clinical trial is registered with ChiCTR-PRCH-14004372.

Vincristine-induced polyneuropathy in a child with stage I Wilms' tumour presenting with unilateral abducens nerve palsy

A 4-year-old boy presented with right esotropia while receiving vincristine and dactinomycin for stage I Wilms' tumour according to the National Wilms Tumour Study-5 protocol. On examination, he had isolated limitation of his right lateral gaze. CT of the brain and cerebrospinal fluid examination were normal. A nerve conduction velocity study which was performed on the peripheral nerves revealed predominant motor polyneuropathy compatible with axonal loss involving the upper limbs. The patient had received a cumulative vincristine dose of 17 mg/m(2) before developing esotropia. Vincristine-induced abducens nerve mononeuropathy and subclinical motor polyneuropathy was suspected. Unilateral esotropia markedly improved after the discontinuation of vincristine and a short course of oral pyridoxine treatment.

Children's Oncology Group's 2013 blueprint for research: renal tumors

Renal malignancies are among the most prevalent pediatric cancers. The most common is favorable histology Wilms tumor (FHWT), which has 5-year overall survival exceeding 90%. Other pediatric renal malignancies, including anaplastic Wilms tumor, clear cell sarcoma, malignant rhabdoid tumor, and renal cell carcinoma, have less favorable outcomes. Recent clinical trials have identified gain of chromosome 1q as a prognostic marker for FHWT. Upcoming studies will evaluate therapy adjustments based on this and other novel biomarkers. For high-risk renal tumors, new treatment regimens will incorporate biological therapies. A research blueprint, viewed from the perspective of the Children's Oncology Group, is presented.

The evolution of treatment for Wilms tumor

The prognosis for children with Wilms tumor (WT) has improved dramatically as the result of advances in surgical techniques, anesthesia, and supportive care. During the last three decades, the National Wilms Tumor Study Group (NWTSG), the International Society of Pediatric Oncology (SIOP), and the United Kingdom Children's Cancer Study Group (UKCCSG) conducted sequential studies of treatments for children with WT. The National Wilms Study Group demonstrated that radiation therapy is not necessary for those with Stage I and II, favorable histology Wilms tumor, and that the dose necessary for local control for those with local Stage III disease is 1050 to 1080 cGy. Administration of actinomycin D and doxorubicin using a single dose rather than divided dose schedule produced less myelosuppression and equivalent outcomes. Loss of heterozygosity for chromosomes 1p and 16q was associated with an inferior outcome. Areas for future investigation include the role of whole lung irradiation in the treatment of those with pulmonary metastases, the use of parenchymal sparing surgical techniques for removal of Wilms tumors, and identification of minimal necessary therapy.

Cooperative group trials in pediatric oncology: the surgeon's role

The early history of the pediatric cooperative group trials is reviewed, and the surgeons who played a critical role in their formation are discussed. The vital information provided from the tumor specimens submitted as part of the protocols is presented, as well as how this information advanced our management of infants and children treated on current protocols of the Children's Oncology Group. Finally, a survey of the surgeons currently active in the clinical trials defined the "critical lessons" learned from the sequence of protocols by the cooperative groups which have advanced our surgical treatment of patients today.

Is antenatal detection of Wilms' tumor a bad prognostic marker?

Antenatal detection of Wilms' tumor is rare and only nine cases have been reported till now in the English literature. We report a case of a 7-month-old child with prenatally detected renal mass managed by nephroureterectomy associated with intraoperative spill. The child developed recurrence while on DD4A chemotherapy. Salvage chemotherapy was initiated but there was no response after two cycles and the child expired due to tumor rupture.

Pathological review of Wilms tumor nephrectomy specimens and potential implications for nephron sparing surgery in Wilms tumor

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.

Pediatric urologic oncology

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

Oncologic outcomes of partial versus radical nephrectomy for unilateral Wilms tumor

BACKGROUND

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.

METHODS

We identified all published cases of PN for UWT. Cases of elective PN for UWT were analyzed for tumor stage, presence, timing and location of disease recurrence, and overall survival (OS). Eighty-two patients had adequate data for analysis. For comparison, these endpoints were collected on consecutive children undergoing RN for UWT from 1985 to 2010 at our institution.

RESULTS

Of the 82 PN patients, tumor stage was: I-64, II-10, III-6, IV-2. Of the 121 RN patients, the staging was: I-24, II-45, III-29, IV-23. In the PN group, at a median of 48 months (3-372), the recurrence-free survival (RFS), local RFS and OS were 89.1%, 92.7%, and 95.1%, respectively. In the RN group, at a median of 69 months (0-214), the RFS, local RFS, and OS were 83.1%, 95.0%, and 95.0%, respectively. After controlling for stage, there were no statistically significant differences in the above oncologic outcomes between the groups.

CONCLUSION

Based on reported data, the oncologic outcomes of PN for UWT in selected patients do not appear to differ from those of RN. PN for appropriately selected patients with UWT should be studied in prospective, co-operative group trials.

Outcomes of patients with revised stage I clear cell sarcoma of kidney treated in National Wilms Tumor Studies 1-5

PURPOSE

To report the clinical outcomes of children with revised stage I clear cell sarcoma of the kidney (CCSK) using the National Wilms Tumor Study Group (NWTS)-5 staging criteria after multimodality treatment on NWTS 1-5 protocols.

METHODS AND MATERIALS

All CCSK patients enrolled in the National Wilms Tumor Study Group protocols had their pathology slides reviewed, and only those determined to have revised stage I tumors according to the NWTS-5 staging criteria were included in the present analysis. All patients were treated with multimodality therapy according to the NWTS 1-5 protocols.

RESULTS

A total of 53 children were identified as having stage I CCSK. All patients underwent primary surgery with radical nephrectomy. The chemotherapy regimens used were as follows: regimen A, C, F, or EE in 4 children (8%); regimen DD or DD4A in 33 children (62%); regimen J in 4 children (8%); and regimen I in 12 children (22%). Forty-six patients (87%) received flank radiation therapy (RT). Seven children (13%) did not receive flank RT. The median delay between surgery and the initiation of RT was 9 days (range, 3-61). The median RT dose was 10.8 Gy (range, 10-36). The flank RT doses were as follows: 10.5 or 10.8 Gy in 25 patients (47%), 11-19.9 Gy in 2 patients (4%), 20-29.9 Gy in 9 patients (17%), and 30-40 Gy in 10 patients (19%). The median follow-up for the entire group was 17 years (range, 2-36). The relapse-free and cancer-specific survival rate was 100% at the last follow-up examination.

CONCLUSIONS

The present results have demonstrated that children with revised stage I CCSK using the NWTS-5 staging criteria have excellent survival rates despite the use of varying RT doses and chemotherapy regimens in the NWTS 1-5 protocols.