Renal salvage procedures in patients with synchronous bilateral Wilms' tumors: a report from the National Wilms' Tumor Study Group

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

INTRODUCTION

The purpose of this study is to examine the outcomes in children with anaplastic bilateral Wilms tumor (BWT) from study AREN0534 in order to define potential prognostic factors and areas to target in future clinical trials.

METHODS

Demographic and clinical data from AREN0534 study patients with anaplasia (focal anaplasia [FA], or diffuse anaplasia [DA]) were compared. Event-free survival (EFS) and overall survival (OS) were reported using Kaplan-Meier estimation with 95% confidence bands, and differences in outcomes between FA and DA compared using log-rank tests. The impact of margin status was analyzed.

RESULTS

Twenty-seven children who enrolled on AREN0534 had evidence of anaplasia (17 DA, 10 FA) in at least one kidney and were included in this analysis. Twenty-six (96%) had BWT. Nineteen percent had anaplastic histology in both kidneys (four of 17 DA, and one of 10 FA). Forty-six percent with BWT had bilateral nephron-sparing surgery (NSS); one child who went off protocol therapy, eventually required bilateral completion nephrectomies. Median follow-up for EFS and OS was 8.6 and 8.7 years from enrollment. Four- and 8-year EFS was 53% [95% confidence interval (CI): 34%-83%] for DA; 4-year EFS was 80% [95% CI: 59%-100%], and 8-year EFS 70% [95% CI: 47%-100%] for FA. Three out of 10 children with FA and eight out of 17 children with DA had events. EFS did not differ statistically by margin status (p = .79; HR = 0.88). Among the six children who died (five DA, one FA), all experienced prior relapse or progression within 18 months.

CONCLUSION

Events in children with DA/FA in the setting of BWT occurred early. Caution should be taken about interpreting the impact of margin status outcomes in the context of contemporary multimodal therapy. Future targeted investigations in children with BWT and DA/FA are needed.

A Single Center Experience With Bilateral Wilms Tumor

BACKGROUND

Wilms tumor (WT) is the most common pediatric renal malignancy and bilateral disease (BWT) occurs in 5% of cases and is associated with poor outcomes. Management of BWT includes chemotherapy and oncologic resection while preserving renal function. Previous literature has demonstrated variable approaches in BWT treatment. The aim of this study was to examine a single institution experience and outcomes with BWT.

METHODS

A retrospective chart review was performed for all patients with WT treated at a free-standing tertiary children's hospital between 1998 and 2018. Patients with BWT were identified and treatment courses were compared. Outcomes of interest included need for dialysis post-operatively, need for renal transplantation post-operatively, disease recurrence, and overall survival.

RESULTS

Of 120 children with WT, 9 children (6F:3M) of median age 32 months (IQR: 24-50 months) and median weight 13.7 kg (IQR: 10.9-16.2 kg) were diagnosed with and treated for BWT. Pre-operative biopsies were obtained in 4/9 patients, 3 of whom received neoadjuvant chemotherapy and 1 who underwent radical nephrectomy. Of the 5 patients who did not undergo biopsy, 4/5 were treated with neoadjuvant chemotherapy, and 1/5 underwent upfront nephrectomy. Post-operatively, 4/9 children required dialysis, of whom 2 subsequently underwent renal transplantation. Two patients were lost to follow-up, and of the remaining 7 patients, disease recurrence occurred in 5/7 children and overall survival was 71% (n=5).

CONCLUSION

Management of BWT varies regarding the use of pre-operative biopsy, neoadjuvant chemotherapy, and extent of disease resection. Further guidelines on treatment protocols may optimize outcomes in children with BWT.

Utilizing RENAL nephrometry in pediatric patients undergoing nephron-sparing surgery for renal tumors: A single-institutional cohort

INTRODUCTION

RENAL Nephrometry is a complexity score validated in adults with renal tumors and describes the likelihood of complication after partial nephrectomy (PN). Utilization in pediatrics has been limited. Thus, our goal is to quantify inter-rater agreement as well as determine how scores correlate with outcomes. We hypothesize that the RENAL Nephrometry Score is reproducible in children with renal tumors and is related to perioperative and post-operative complications.

METHODS

All pediatric patients who underwent PN for a renal mass from 2006 to 2019 were identified. Patient data, operative details, and outcomes were aggregated. Pre-operative CT/MR imaging was anonymized and scored by 2 pediatric radiologists and 2 pediatric urologists using RENAL Nephrometry metrics. Statistical analysis utilized Fleiss' kappa and the intraclass correlation coefficient (ICC). Comparative analyses were performed based on Nephrometry Score <9 and ≥ 9.

RESULTS

28 patients undergoing 33 PN were identified. Median age at surgery was 3.2 years (IQR 1.8-4.0). There is moderate-good agreement across scorers on the domains of RENAL Nephrometry Score, with the lowest agreement noted for anterior vs posterior tumors. Comparing patients with scores <9 and ≥ 9, there was increased operative time (357 vs 267 min, p = 0.003) and LOS for those with a higher score, but no difference in the incidence of 30-day complications.

CONCLUSION

RENAL Nephrometry Score is an easily reproducible complexity score for renal tumors in pediatric patients. Higher scores are associated with increased length of stay and estimated blood loss but not complications. Reporting of nephrometry scores in future publications on pediatric renal tumors should become standard in the literature.

How does Nephroblastomatosis impact the prognosis of unilateral Wilms tumor?

PURPOSE

We aimed to explore whether Nephroblastomatosis (Nbm) has an effect on the prognosis of Wilms tumor (WT), and compare the relapse-free survival (RFS) and overall survival (OS) after surgery of WT patients with or without Nbm.

METHODS

We retrospectively analyzed the clinical data of children with WT admitted to our department from April 2010 to September 2021. The enrolled patients were divided into two groups according to whether they were combined with Nbm histologically or not, the Nbm group for patients accompany with Nbm and the non-Nbm group for pure WT. All patients underwent a standardized comprehensive treatment according to National Wilms Tumor Study 5. Clinical variables, pathological results, and the prognosis were collected during follow-up.

RESULTS

A total of 345 patients were finally enrolled in this study, of which 299 patients in the non-Nbm group and 46 patients in the Nbm group. Univariate Cox analysis revealed that Nbm was not the risk factor of either OS or RFS. The difference of postoperative RFS (P = 0.66) and OS (P = 0.68) between two groups was not significant. Subgroup analysis revealed that the RFS and OS between the non-Nbm group and the Nbm group had no statistical difference under the condition of same stage (low grade and high grade), same histology (favorable histology and unfavorable histology), same surgical approach (nephrectomy and nephron-sparing surgery), with or without lymph node metastasis (P > 0.05).

CONCLUSION

Although Nbm had a strong correlation with the occurrence of WT, a combined Nbm did not increase the risk of metastasis and poor prognosis of WT. After complete surgical resection followed by standardized treatment, the long-term RFS and OS were not different from pure WT. IEC-C-006-A04-V.06 retrospectively registered.

Nephron sparing surgery outcomes in Wilms' tumor: is it ready for primetime?

PURPOSE

Radical nephrectomy is the gold standard in Wilms tumor (WT) treatment and is combined with adjuvant treatment in early stage disease or performed after neo adjuvant therapy in advanced disease. With the development of novel adjuvant and neoadjuvant therapeutic strategies, there is increasing interest in organ preserving procedures in several adult malignancies. Potential long-term complications of living with a single kidney include hyperfiltration syndrome, hypertension, and fluid retention. If NSS (Nephron Sparing Surgery) were to be adopted for the treatment of WT it would be necessary to preserve the gains in Overall Survival (OS) seen with current treatment protocols. With this in mind we undertook a study of outcomes of NSS performed in the USA using a large population-based registry.

METHODS

We retrospectively queried the SEER Research Plus 18-registries Database 2010-2018 for patients 18 years old or younger with Wilms tumor as determined by ICD-O-3 code 8960. Clinical and demographic data was extracted, and statistical analysis was performed in GraphPad PRISM 9 with bivariate analysis and log-rank analysis to determine survival.

RESULTS

1087 patients with Wilms tumor were identified. 73 (6.72%) underwent nephron-sparing surgery. The final cohort consisted of 45 patients (64%) who underwent unilateral NSS and 25 patients (36%) who underwent bilateral NSS. Three were excluded from analysis due to non-renal origin of tumor. Mean age was 3.214 years (std dev 3.807). Demographics were similar between the groups, apart from younger age associated with bilateral tumor (p = 0.0441). No differences were found between radiation use (p = 0.4280), chemotherapy use (p = 0.5479), tumor size (p = 0.2186), positive regional lymph nodes (p = 0.707). Log-rank analysis demonstrated that cancer-specific survival was not significantly different between unilateral and bilateral NSS or radical nephrectomy (p = 0.4539).

CONCLUSION

NSS may preserve renal function long-term, an important consideration in the pediatric population. Prospective study is necessary to select the appropriate patient subsets who may benefit from NSS in WT.

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

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

Wilms tumor: a review of current surgical controversies

Overall survival (OS) for children with Wilms tumor (WT) currently stands at around 90%. This is markedly improved from the survival rates of around 30% reported in the middle of the last century. This improvement is due to the development of multimodal treatment for this disease, based on the evidence yielded through international collaboration on trials conducted by the Société Internationale d'Oncologie Pédiatrique (SIOP) and the Children’s Oncology Group (COG). In this article, we review some of the current surgical controversies surrounding the management of WT.

Technical Considerations for Nephron-Sparing Surgery in Children: What Is Needed to Preserve Renal Units?

BACKGROUND

Chemotherapy is used preoperatively for children with bilateral Wilms tumor (BWT) or unilateral high-risk Wilms tumor (UHRWT) to promote tumor regression to facilitate renal preservation with nephron-sparing surgery (NSS). In adults, various surgical techniques have been described to preserve renal tissue. Few studies have examined the use of surgical adjuncts in NSS in children with renal tumors.

METHODS

We performed a multi-institutional retrospective review of patients with BWT or UHRWT. Patient demographics, tumor size at diagnosis, following neoadjuvant chemotherapy, utilization of surgical adjuncts including intraoperative ultrasound (IOUS), margin status, complications, renal function, and follow-up were recorded.

RESULTS

The cohort comprised 23 patients: 18 BWT, 3 UHRWT, and 2 patients with solitary kidney. Twenty-two of the 23 patients had successful NSS. IOUS was used 19 times, and seven had positive margins after surgery. Cooling/vascular isolation was used six times. At a median follow-up of 18 mo, median estimated glomerular filtration rate Schwartz was 126 mL/min/1.73 m² and median serum creatinine 0.39 mg/dL in the 22 patients who had successful NSS. There have been no tumor recurrences.

CONCLUSIONS

In patients with BWT and UHRWT, surgical adjuncts such as cooling/vascular isolation are uncommonly performed. IOUS may be helpful but does not guarantee negative microscopic margins.

LEVEL OF EVIDENCE

Level 4, Case series with no comparison group.

Management of bilateral Wilms tumours

Wilms tumour is named after Max Wilms. It is an embryonal tumour derived from the metanephros. It is the commonest childhood renal tumour and the third commonest paediatric malignancy. Synchronous bilateral Wilms tumours (BWT) represent 4-7% of all Wilms tumours (WT) and present at a younger age than unilateral Wilms tumours. At least 10% of synchronous BWTs have unfavourable histology, and up to 22% are associated with genitourinary abnormalities, aniridia, WAGR syndrome, Denys-Drash syndrome, hemihypertrophy, or one of the other overgrowth syndromes. The long-term disease-free survival rate for patients with unilateral WT is approaching 90%, and is around 70% for those with metastatic disease. For both synchronous and metachronous Wilms tumours the prognosis is less favourable with reported cure rates approaching 80% in the best centres and lower in resource poor settings. There is potential for a reduced quality of life due to renal insufficiency and the possible need for renal transplantation. The major clinical challenge in BWTs is preservation of functioning renal tissue using nephron-sparing surgical techniques, while achieving cure with minimum therapy-related morbidity. Mortality is generally associated with progressive disease of anaplastic tumours. Chemotherapy followed by nephron-sparing surgery has been able, in most cases, to eradicate the tumour while preserving renal function. Radiotherapy has largely been avoided because of fears of long-term radiation injury to the residual functioning renal mass. Patient selection, appropriate pre- and post-operative chemotherapy and skilled surgical techniques all contribute to excellent outcomes where these are achievable.

Management of bilateral Wilms tumours

Wilms tumour is named after Max Wilms. It is an embryonal tumour derived from the metanephros. It is the commonest childhood renal tumour and the third commonest paediatric malignancy. Synchronous bilateral Wilms tumours (BWT) represent 4-7% of all Wilms tumours (WT) and present at a younger age than unilateral Wilms tumours. At least 10% of synchronous BWTs have unfavourable histology, and up to 22% are associated with genitourinary abnormalities, aniridia, WAGR syndrome, Denys-Drash Syndrome, hemihypertrophy, or one of the other overgrowth syndromes. The long-term disease-free survival (DFS) rate for patients with unilateral Wilms' tumours is approaching 90%, and is around 70% for those with metastatic disease. For both synchronous and metachronous Wilms tumours the prognosis is less favourable with reported cure rates approaching 80% in the best centres and lower in resource poor settings. There is potential for a reduced quality of life due to renal insufficiency and the possible need for renal transplantation. The major clinical challenge in BWTs is preservation of functioning renal tissue using nephron sparing surgical techniques, while achieving cure with minimum therapy-related morbidity. Mortality is generally associated with progressive disease of anaplastic tumours. Chemotherapy followed by nephron sparing surgery has been able, in most cases, to eradicate the tumour while preserving renal function. Radiotherapy has largely been avoided because of fears of long term radiation injury to the residual functioning renal mass. Patient selection, appropriate pre- and post-operative chemotherapy and skilled surgical techniques all contribute to excellent outcomes where these are achievable.

Management of Bilateral Wilms' Tumor: Our Experience

Management of bilateral Wilms' tumor is particularly challenging, considering the chances of recurrence and long-term renal function for affected patients. Aggressive surgical resection to prevent recurrence must be balanced with the desire to preserve renal function. We evaluated our experience in the management of bilateral Wilms' tumor stressing the challenges encountered in decision making and the role of nephron sparing surgery. We had four children presenting with bilateral Wilms' tumor. All of them were appropriately staged and given standard chemotherapy as per NWTS-5 guidelines. Tumors were considered to have a 'good' response to chemotherapy if sufficient tumor shrinkage was observed so that renal hilum was seen free of tumor and vice versa. Nephron-sparing surgery was considered in all and was performed when feasible, followed by completion adjuvant chemotherapy. All patients were followed up with serial ultrasound scans (3-6 monthly) and CECT abdomen (yearly once). Blood urea and serum creatinine, hypertension, and proteinuria were assessed during follow-up visits. All four children received neo-adjuvant chemotherapy as per NWTS-5 guidelines. The first child had poor response to chemotherapy and was considered for left radical and right partial nephrectomy. However, patient attenders refused any surgical intervention and the child was taken home. The second child had a 'good' response on left side and was planned for left partial and right radical nephroureterectomy based on pre-operative imaging analysis. However, intra-operatively, bilateral partial nephrectomy with good margins was feasible. The third child though, showed 'poor' response to pre-op chemotherapy and warranted bilateral nephroureterectomy, right partial and left radical nephroureterectomy was feasible. However, in the fourth child, we were not able to perform nephron sparing surgery and left nephroureterectomy with right tumor biopsy was done. Following this, child was started on 2nd-line chemotherapy, now awaiting right partial nephrectomy. The second child is on follow up for 1.5 years, doing well. However, the third child expired 1.5 years following surgery due to recurrence (lung metastasis). Management of bilateral Wilm's tumor is challenging and nephron-sparing surgery should be considered in all patients having bilateral Wilm's tumor with favorable histology, even if pre-operative imaging studies suggest that the lesions are unresectable.

Overall Survival and Renal Function of Patients With Synchronous Bilateral Wilms Tumor Undergoing Surgery at a Single Institution

OBJECTIVES

Wilms tumor is the most common renal cancer in children. Approximately 5% of children with Wilms tumor present with disease in both kidneys. The treatment challenge is to achieve a high cure rate while maintaining long-term renal function. We retrospectively reviewed our institutional experience with nephron sparing surgery (NSS) in patients with synchronous bilateral Wilms tumor (BWT) operated on between 2001 and 2014.

METHODS

Imaging studies, surgical approach, adjuvant therapy, and pathology reports were reviewed. Outcomes evaluated included surgical complications, tumor recurrence, patient survival, and renal function, as assessed by estimated glomerular filtration rate.

RESULTS

A total of 42 patients with BWT were identified: 39 (92.9%) patients underwent bilateral NSS; only 3 patients (7.1%) underwent unilateral nephrectomy with contralateral NSS. Postoperative complications included prolonged urine leak (10), infection (6), intussusception (2), and transient renal insufficiency (1). Three patients required early (within 4 months) repeat of NSS for residual tumor. In the long-term, 7 (16.7%) patients had local tumor recurrence (managed with repeat NSS in 6 and completion nephrectomy in 1) and 3 had an episode of intestinal obstruction requiring surgical intervention. Overall survival was 85.7% (mean follow-up, 4.1 years). Of the 6 patients who died, 5 had diffuse anaplastic histology. All of the patients had an estimated glomerular filtration rate more than 60 mL/min/1.73 m at the last follow-up; no patient developed end-stage renal disease.

CONCLUSIONS

In patients with synchronous, BWT, bilateral NSS is safe and almost always feasible, thereby preserving maximal renal parenchyma. With this approach, survival was excellent, as was maintenance of the renal function.

Nephron-sparing surgery for Wilms tumor: A systematic review

INTRODUCTION

Radical nephrectomy (RN, or total nephrectomy) is the current gold-standard surgical treatment for children with Wilms tumors (WT). However, nephron-sparing surgery (NSS, or partial nephrectomy) has recently been gaining increasing attention. The objective of this systematic review is to compare the effectiveness of NSS as compared with RN for the treatment of children with WT.

METHODS

We searched the Cochrane Controlled Trials Register, clinicaltrials.gov, MEDLINE, EMBASE, Google Scholar, and recently presented meeting abstracts for reports in English. The bibliographies of included studies were then hand-searched for any missed articles. The protocol was prospectively registered. Manuscripts were assessed and data abstracted in duplicate with differences resolved by the senior author. Owing to high heterogeneity among the final included studies, only a qualitative systematic review was performed; no formal meta-analysis was undertaken.

RESULTS

We identified 694 articles, 118 of which were selected for full-text review and 66 of which were included in the final analysis. Most studies were single- or multi-institution retrospective case series (60, 91%), with a small number of prospective cohort studies (6, 9%) and 1 administrative database analysis. Most studies were from Europe (27, 41%) or North America (21, 32%). Nearly half (32, 48%) of studies those were included were dated from 2010 or later. In total, data on 4,002 patients were included, of whom 1,040 (26%) underwent NSS and 2,962 (74%) underwent NSS. Reported rupture rates were similar between RN and NSS (13% vs. 7%), as were recurrence rates (12% vs. 11%) and survival rates (85% vs. 88%). However, these comparisons are limited by inherent biases in the design and reporting of most included studies.

CONCLUSIONS

Most contemporary studies reporting the use of NSS in children with WT report similar long-term outcomes to RN. However, most existing studies are limited by their small numbers, inconsistent reporting, and methodological biases. There are significant opportunities for future research on the use of NSS in children with WT, including issues related to surgical quality, optimal technique, timing and duration of chemotherapy, and variation in the use of NSS among centers.

Management and outcomes in massive bilateral Wilms' tumors

Purpose:

To evaluate the outcome of children with bilateral Wilms’ tumor (BWT) treated on All India Institute of Medical Sciences-Wilms Tumor-99 (AIIMS-WT-99) protocol.

Materials and Methods:

All children with BWT, registered in our solid tumor clinic from August 1999 through December 2010 were included.

Results:

Of the 178 fresh cases of Wilms Tumor (WT) treated during this period, 11 (6.2%) had bilateral involvement. All patients except one (12 and 3 cm), had massive bilateral tumors of more than 10 cm on each side. There were eight boys and three girls in the age range 6–30 months. One patient had Denys-Drash syndrome. Twenty renal units were operated upon (12 tumorectomy, five partial nephrectomy, and three nephrectomies), while one patient with inferior vena cava (IVC) thrombus died of renal failure. Tumor spill occurred in three units, lymphnode was positive in two patients. Local recurrence occurred in four patients (six of 18 renal units (33%)—two bilateral and two unilateral). There was one recurrence in the liver that was treated with radio-frequency ablation. The 5-year overall survival (OS) was 90% (95% confidence interval (CI) = 50.8–98.6) and the relapse free survival (RFS) was 38% (95% CI = 6.1–71.6).

Conclusion:

Massive BWT respond poorly to preoperative chemotherapy, are often not amenable to partial nephrectomy/tumorectomy and have a higher local recurrence rate, giving a poor RFS.

Variation in use of nephron-sparing surgery among children with renal tumors

OBJECTIVE

Given the negative long-term effects of renal insufficiency, nephron-sparing surgery (NSS) is increasingly discussed for the treatment of pediatric renal tumors. We sought to examine variation in practice patterns of NSS among children with renal tumors.

MATERIALS AND METHODS

We performed a retrospective cohort analysis of claims data for pediatric inpatient admissions captured by the Kids Inpatient Database (1997-2009). We identified children with renal tumors who underwent surgery, including radical nephrectomy (RN) and NSS. We used multivariable logistic regression to assess the relationship between use of NSS and various clinical, demographic, and geographic predictors of interest.

RESULTS

We identified 10,108 pediatric inpatient admissions for renal tumors. Of these, 1657 were surgical admissions, with 1501 patients (90.5%) undergoing RN and 156 (9.5%) undergoing NSS. On multivariable analysis, NSS was associated only with a concomitant diagnosis of renal insufficiency (relative ratio [RR] 3.37, p = 0.01) and surgery in the Northeastern USA (RR 3.07, p = 0.03). Race/ethnicity, age, payer type, procedure year, and other non-clinical factors were not significantly associated with NSS.

CONCLUSION

In a large, nationwide pediatric cohort, RN remains the most common surgical intervention for renal tumors. NSS is significantly associated with a diagnosis of renal insufficiency, but not non-clinical factors such as patient gender or race. © 2014 Published by Elsevier Ltd on behalf of Journal of Pediatric Urology Company.

Bilateral Wilms tumors treated according to the Japan Wilms Tumor Study Group protocol

BACKGROUND

The introduction of multimodal therapy has improved the survival rate of bilateral Wilms tumors (BWT); however, the results are still not satisfactory in terms of the renal preservation. To establish a new treatment strategy for BWT, we reviewed the results of the cases registered in the Japan Wilms Tumor Study Group (JWiTS).

PROCEDURE

This analysis concerned patients with synchronous BWT registered in the JWiTS between 1996 and 2011. In these patients, the management of BWT included initial tumor resection or biopsy followed by chemotherapy. The details of the treatments and outcomes were analyzed.

RESULTS

Among the 355 cases registered in the JWiTS database, 31 (8.7%) had BWT. They were 16 males and 15 females with a mean age of 15.5 months. Preoperative chemotherapy was performed in 24 cases. Bilateral nephron-sparing surgery (NSS) was achieved in 10 of 28 cases (36%). All of the cases were of favorable nephroblastoma without anaplasia, and a WT1 mutation was detected in 21 of the 27 cases (78%) examined. The 5-year overall survival was 92.6%; however, 10 children (40%) developed impaired renal function and three of them developed renal failure.

CONCLUSIONS

The long-term survival rates for patients with synchronous BWT have improved. However, more than half of patients receive nephrectomy. The protocol should be changed to improve the rate of preservation of the renal parenchyma. Preoperative chemotherapy should be performed to shrink the tumors in every case, and subsequent NSS should be carried out after a central imaging evaluation.

Use of nephron sparing surgery and impact on survival in children with Wilms tumor: a SEER analysis

PURPOSE

Nephron sparing surgery is the standard of care for many adults with renal tumors and has been described in some children with Wilms tumor. However, beyond case series the data concerning nephron sparing surgery application and outcomes in patients with Wilms tumor are scarce. We examined nephron sparing surgery outcomes and factors associated with its application in children with Wilms tumor.

MATERIALS AND METHODS

We retrospectively reviewed the 1998 to 2010 SEER database. We identified patients 18 years old or younger with Wilms tumor. Clinical, demographic and socioeconomic data were abstracted, and statistical analysis was performed using multivariate logistic regression (predicting use of nephron sparing surgery limited to unilateral tumors smaller than 15 cm) and Cox regression (predicting overall survival) models.

RESULTS

We identified 876 boys and 956 girls with Wilms tumor (mean ± SD age 3.3 ± 2.9 years). Of these patients 114 (6.2%) underwent nephron sparing surgery (unilateral Wilms tumor in 74 and bilateral in 37). Median followup was 7.1 years. Regarding procedure choice, nephron sparing surgery was associated with unknown lymph node status (Nx vs N0, p <0.001) and smaller tumor size (p <0.001). Regarding survival, only age (HR 1.09, p = 0.002), race (HR 2.48, p = 0.002), stage (HR 2.99, p <0.001) and lymph node status (HR 2.17, p = 0.001) predicted decreased overall survival. Survival was not significantly different between children undergoing nephron sparing surgery and radical nephrectomy (HR 0.79, p = 0.58).

CONCLUSIONS

In children with Wilms tumor included in the SEER database nephron sparing surgery has been infrequently performed. Nephron sparing surgery application is associated with smaller, bilateral tumors and with omission of lymphadenectomy. However, there are no evident differences in application of nephron sparing surgery based on demographic or socioeconomic factors. Despite lymph node under staging, overall survival is similar between patients undergoing nephron sparing surgery and radical nephrectomy.

Nephron sparing surgery for unilateral non-syndromic wilms tumor

The initial therapy for most children with Wilms tumor is radical nephrectomy. Several centers, have explored the role of Nephron-sparing procedures in children with unilateral non-syndromic Wilms tumors. The primary motivation for this approach is concern about late occurrence of renal dysfunction after unilateral nephrectomy. We report our experience with NSS for unilateral non-syndromic Wilms tumor. We reviewed the records of nine children who underwent nephron sparing surgery for unilateral, nonsyndromic Wilms tumors at our Hospital between Jan 2000 through Jan 2012. All patients received preoperative chemotherapy with two drugs (vincristine, and dactinomycin) following which patients underwent tumor resection. Subsequent renal function was assessed by estimating the glomerular filtration rate using creatinine clearance and other measures of long-term renal function assessment included blood pressure evaluation and the need for antihypertensive medications. During the study period nine children with a mean age 19.66 ± 14.37 months at diagnosis and presenting with unilateral non-syndromic Wilms tumor underwent nephron sparing surgery. In all the nine children, the renal plane of resection showed a tumor-free margin. Post-operative serum creatinine repeated at the end of 3 months revealed maintenance of good renal function in all children. Nephron sparing surgery is a safe and effective option in the management of early stage unilateral non-syndromic Wilms tumor. It is oncologically safe and does not lead to decreased local tumor control. The function of the kidney remnant remains rather well.

The management of bilateral Wilms tumor

Wilms tumor (WT) is the most common malignant renal tumor in childhood. Approximately 5-7% of WT patients present with bilateral disease, either synchronously or metachronously. Bilateral WT usually occurs in younger children and more often in girls. Management of a child with bilateral WT is very challenging. In contrast to unilateral WT, there has not been uniform agreement about the therapeutic strategy in the management of bilateral WT. As surgery is a critical component in the treatment of WT, the aim is to achieve a high cure rate while maintaining adequate long-term renal function in patients with bilateral WT. In the past, radical surgical procedures which lead to the patients on dialysis have been traditionally recommended in these patients. After several multicentre trials, bilateral biopsies followed by pre-operative chemotherapy and then renal salvage surgery have been recommended. The management of bilateral WT has evolved from primary surgical extirpation to kidney-preserving resection after preoperative chemotherapy. Preoperative chemotherapy often results in significant reduction in tumor size, thereby facilitating subsequent renal salvage. The analysis of children with bilateral WT shows that preservation of renal parenchyma is possible following initial preoperative chemotherapy. Only centers with experience in bilateral WT should treat the cases with bilateral WT to provide optimal treatment.

Repeat nephron-sparing surgery for children with bilateral Wilms tumor

BACKGROUND

Renal insufficiency is a significant complication of Wilms tumor treatment in the 5% with bilateral disease. Nephron-sparing surgery (NSS) is recommended after neoadjuvant chemotherapy initially. However, the role of NSS in recurrent disease is unknown. We reviewed our experience to assess the feasibility and oncologic and functional outcomes of repeat NSS for children with recurrent disease.

METHODS

A retrospective review was performed of all children treated at our institution for bilateral, favorable histology (FH) Wilms tumor. Patients undergoing repeat NSS for locally recurrent disease were identified. The outcomes evaluated included tumor recurrence, renal function, and patient survival.

RESULTS

Since 2001, 36 children with bilateral FH Wilms tumor have been treated at our institution. Eight patients (22%) underwent repeat NSS for locally recurrent disease. Two patients had a second local recurrence and underwent a third NSS. Six patients are alive without disease (75%) with an average follow-up of 4.5years. Two patients have died, each with blastemal-predominant histology at repeat NSS. The surviving patients have normal renal function, although two patients require medical management of hypertension.

CONCLUSIONS

Our experience suggests that repeat NSS for local recurrence of FH bilateral Wilms tumor is feasible and affords acceptable oncologic outcome with preservation of renal function. However, more aggressive therapy may be required for patients whose recurrence has blastemal-predominant histology, given the poor outcome for these patients in our series.

Margin status and tumor recurrence after nephron-sparing surgery for bilateral Wilms tumor

PURPOSE

Nephron-sparing surgery (NSS) has been advocated for patients with bilateral Wilms tumor (BWT). We sought to determine whether margin status impacted local tumor recurrence.

METHODS

A retrospective review of patients undergoing NSS for BWT from November 1999 to March 2009 at our institution in which local recurrence rates based on margin status were compared.

RESULTS

Of 21 patients, five (23.8%) had positive margins. These and 2 (9.5%) with focal anaplasia received flank XRT. Seven (33%) patients developed recurrent disease, a mean of 18.0 (range 1.3-39.9) months after NSS. Recurrence rates were similar in patients with positive and negative margins (1/5 [20%] vs 6/16 [37.5%]; p = 0.47). Hypertension occurred more frequently in patients who received XRT (57.1% vs 28.6%). At a median follow-up of 28.6 months (range 5.2-142.3), 19 patients are alive, without evidence of disease; one patient (with a positive margin at initial NSS) died of metastatic anaplastic WT and another died of a brain tumor. One patient, with multiple risk factors, developed renal failure.

CONCLUSIONS

In our experience, local recurrence rates after NSS were not affected by surgical margin status although all patients with positive margins received XRT. These results support the aggressive use of NSS for patients with BWT.

Oncology: the role of partial nephrectomy in Wilms tumor

Wilms tumor represents the most common pediatric renal malignancy and the fourth most common childhood cancer overall. Overall survival from Wilms tumor has increased to over 90 % secondary to multidisciplinary therapy and multi-institutional cooperative group trials. Recent therapeutic focus has shifted to reduction in treatment morbidity and renal preservation while maintaining the high survival rates. Partial nephrectomy is an integral component of the multimodal treatment protocols for Wilms tumor patients with bilateral disease, solitary kidney, or predisposing syndromes. Recent consideration has been given to utilization of nephron sparing surgery (NSS) in carefully selected patients with nonsyndromic unilateral Wilms tumor. While long-term, prospective data in this subgroup of patients is not yet available, case series demonstrate comparable oncologic outcomes after partial versus radical nephrectomy. The relative rarity of Wilms tumor, especially those amenable to upfront partial nephrectomy, presents a challenge to conducting controlled trials.

Bilateral Wilms' tumour in a developing country: a descriptive study

PURPOSE

To present our experience of 20 children with bilateral Wilms' tumour seen in a resource-challenged environment over a 10-year period.

METHOD

All patients with a diagnosis of bilateral synchronous Wilms' tumour were identified and recruited.

RESULTS

Study patients represented 11 % of a cohort of 177 new patients with Wilms' tumour seen over the same period. Three patients had a syndromic predisposition to Wilms' tumour. Metastatic disease was seen at presentation in four patients (20 %) and three children presented with unilateral tumour rupture. One patient presented with paraplegia and one with obstruction of the duodenum. All children received neoadjuvant chemotherapy. One HIV-infected child died of IRIS after neoadjuvant treatment, but before surgery. One child died of progressive disease after unilateral nephrectomy. Nephron-sparing surgery was performed in 22 kidneys and 15 kidneys were removed in toto. Following enucleation of tumours, three children had positive margins. Discordant histopathology was seen in 53 % of patients. Overall survival at 2 years is 85 %.

CONCLUSION

Despite significant co-morbidity and advanced disease, bilateral Wilms' tumour is a treatable disease in a resource-constrained environment.

Synchronous bilateral Wilms tumor: a report from the Associazione Italiana Ematologia Oncologia Pediatrica (AIEOP)

BACKGROUND

The optimal management of bilateral Wilms tumor (BWT) is challenging, and their survival is lower than for unilateral tumors. This report discusses a large series of BWTs treated in Italy in the last 2 decades.

METHODS

This analysis concerns patients with synchronous BWT registered at Associazione Italiana Ematologia Oncologia Pediatrica (AIEOP) centers between 1990 and 2011; details on their treatment and outcome are presented and discussed.

RESULTS

Ninety BWTs were registered in the AIEOP Wilms tumor database. Preoperative chemotherapy was given for a median 12 weeks before definitive tumor resection was attempted. Forty-eight percent of the patients had preservation of bilateral renal parenchyma. The proportion of bilateral nephron-sparing surgeries was not higher in the 37 patients initially given doxorubicin/vincristine/actinomycin D (32%) than in the 43 children receiving vincristine/actinomycin D alone (58%). The 4-year disease-free survival rate was 66.5% ± 5% and overall survival was 80% ± 5% for the cohort as a whole. The 4-year disease-free survival (overall survival) for 18 children with diffuse anaplasia or postchemotherapy blastemal-type tumors was 51% ± 13% (62% ± 13%), as opposed to 72% ± 3% (88% ± 4%) for 68 children with a favorable histology (log-rank P = .04 [P = .007]).

CONCLUSIONS

These results provide further evidence that the optimal duration and choice of drugs for preoperative chemotherapy remain an open question. Outcome remained significantly worse for BWT than for unilateral Wilms tumor. To enable the conservative treatment of as many affected kidneys as possible, only centers with experience in BWT should manage such cases.

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.

Bilateral Wilms tumors (WT) treated with the SIOP 93 protocol in France: epidemiological survey and patient outcome

BACKGROUND

The treatment of bilateral Wilms tumors (WT) requires multimodality therapy with individualized decision to ensure cure while preserving as much renal parenchyma as possible.

PROCEDURE

We analyzed the clinical records of 49 children with bilateral WT treated in France between 1993 and 2001, according to the SIOP-93 guidelines (individual treatment program: Treatment was continued as long as there was imaging evidence of tumor regression). Pathology reports, duration of preoperative chemotherapy and surgical records were also reviewed. Overall Survival (OS) and Event-Free Survival (EFS) rates were studied and relationships between possible prognostic factors and survival were assessed.

RESULTS

Imaging studies revealed bilateral involvement in 98% of the cases. Whatever the response to preoperative chemotherapy, the mean duration of neoadjuvant chemotherapy was 80 days (Q1-Q3: 47-89 days). Forty-eight children underwent nephron sparing surgery (NSS) at least for one kidney and 19 for both. Five-year EFS and OS rates were, respectively, 83.4 and 89.5%. Only the most advanced stages were shown to affect OS (P = 0.03). At study endpoint, end-stage renal disease (ESRD) was reported in seven children, associated with a predisposing phenotype in three.

CONCLUSIONS

Results of this study demonstrate a favorable outcome of patients with bilateral WT receiving an individual treatment program. With a tailored approach to treatment according to the tumor response, 77% of our patients were operated before the third month of preoperative chemotherapy. In spite of good survival, 14% of our patients have ESRD.

Bilateral Wilms' tumor: Mansoura multi-centers 15 years experience

Purpose. Bilateral Wilms' tumor (WT) is a challenge. Aggressive surgical resection is needed to prevent recurrence. We revised the clinico-epidemiological criteria of bilateral WT patients in our locality and relation to outcome.

Subjects and methods. 462 WT patients were registered in three medical centers at Mansoura, Egypt. Twenty five patients had bilateral WT whose medical records were revised for all clinico-epidemiologic data plus treatment details, toxicity, and outcome.

Results. The mean age was 34.5 months; 64% of cases were female. Abdominal mass was the commonest presentation (72%). Congenital anomalies were reported in two cases (one case showed hemihypertrophy and the other showed aniridia). About 60% had favorable pathology. Nineteen cases had synchronous bilateral WT (76%) and the remaining (six cases) had metachronous tumors. For the synchronous cases, the response rate to preoperative chemotherapy was 79% and nephron sparing surgery for the least involved kidney was possible in all. Survival rate was 74%. Metachronous tumor management included nephrectomy followed by chemotherapy for the initially diagnosed tumors. However, nephron sparing surgery of the contralateral tumors following preoperative chemotherapy was possible in two cases and the survival rate was 33%. No renal failure or any therapy-related complications were reported.

Conclusions. Bilateral WT is predominantly synchronous with favorable histology, with female predilection and possibly congenital anomalies. Preoperative chemotherapy followed by nephron sparing surgery has a favorable outcome with preserved renal function especially in patients with synchronous WT. Response to preoperative chemotherapy had a statistically significant prognostic impact.

Contemporary use of nephron-sparing surgery for children with malignant renal tumors at freestanding children's hospitals

OBJECTIVE

It is widely accepted that, when feasible, nephron-sparing surgery (NSS) is preferable to radical nephrectomy (RN) for treatment of renal tumors in adults. However, RN is more frequently used in children. We sought to compare in-hospital outcomes after NSS and RN for malignant pediatric renal tumors.

MATERIAL AND METHODS

The pediatric health information system (PHIS) combines data from more than 40 North American pediatric hospitals. We queried PHIS to identify children with malignant renal tumors who underwent surgery from 2003 to 2009. We examined whether outcomes (complication rates, cost, and length of stay) differed by procedure type. Multivariate regression models were used to adjust for confounding, and generalized estimating equations were used to adjust for hospital clustering.

RESULTS

We identified 1235 children with renal tumors who underwent RN (91%) or NSS (9%). Patients undergoing RN and NSS had similar median comorbidity scores (P = .98), hospital lengths of stay (each 6.0 days, P = .54), in-hospital charges, ($25,700 vs $37,000, P = .11), and surgical complication rates (16.4 vs 20.5%, P = .24). These outcomes remained similar after adjusting for other patient and hospital factors.

CONCLUSIONS

Most children with malignant renal tumors treated at children's hospitals undergo RN. RN and NSS use were not significantly different in terms of their length of hospital stay, in-hospital charges, and complication rates. Although oncological outcomes are lacking, these data suggest that NSS may be performed in selected children with malignant renal tumors without significantly increasing their hospital charges, length of stay, or surgical complication rates.

Management of Wilms' tumor: NWTS vs SIOP

With the availability of several protocols in the management of Wilms' tumor, there is dilemma in the minds of the treating oncologists or pediatric onco-surgeons as to whether the child should receive upfront chemotherapy or should be operated upon primarily. It is necessary for us to understand why do we follow either of the protocols, NWTS which follows the upfront surgery principle or the SIOP which follows the upfront chemotherapy principle in all stages of the disease. While deciding which protocol to follow, it is imperative to know the pros and cons of the treatment strategies and also to study the outcome patterns in both the treatment regimes which is what this article highlights. In an attempt to compare all the differences in both the major protocols, it was realized that most of our patients in the Indian scenario present with advanced disease and thus poorer outcomes if intensive and appropriate treatment strategies are not utilized. Hence, it is imperative that we should study our own patients through the Indian Wilms' tumor study group and adopt the policies which improve the overall event free survival on a nationwide basis.

Wilms' tumor: An update

Wilms' tumor (WT) is the commonest pediatric renal tumor, predominantly seen in children less than five years of age. The majority of patients present with an abdominal lump and CT scan is the usual imaging modality for determining the extent of disease. With multimodality management, the results of treatment of WT have improved dramatically over the last 50 years. The treatment protocols have been devised and modified repeatedly depending on evidence from randomized trials by several cooperative groups - mainly National Wilms' Tumor Study Group (NWTSG) and the International Society of Pediatric Oncology (SIOP). The NWTSG recommends primary surgery followed by chemotherapy while SIOP advocates four weeks of chemotherapy prior to surgery. The regimen, dose and duration of chemotherapy have been repeatedly modified to reduce toxicity while maintaining efficacy. The role of radiation therapy has also been customized. Most centers have reported excellent survival rates with the modern day treatment protocols, except in patients with an unfavorable histology. The results of treatment of relapsed WT have also improved with newer drugs and combinations being used for the same.

Long-term outcome of bilateral Wilms tumors (BWT)

BACKGROUND

Modern WT management consist of ample chemotherapy, nephron-sparing surgery, and, when indicated, radiotherapy. Survivors may develop renal failure or secondary tumors due to anticancer treatment. We analyzed long-term outcome (follow-up >5 years) after bilateral Wilms tumor (BWT) treatment with respect to survival, renal function, and secondary malignancies.

METHODS

From 41 patients (23 females, 28 synchronous tumors) diagnosed with BWT between 1967 and 2007, 25 (18 females, 14 synchronous) with a follow-up >5 years could be included. Of this subgroup, median age at diagnosis was 1.64 years (range 0.27-5.35), and at maximum follow-up 14.99 years (range 5.40-33.99). Data were retrospectively collected and analyzed.

RESULTS

One patient (4%) died 17.75 years after diagnosis, five (20%) had renal transplants: 3/5 after bilateral nephrectomy for Denys-Drash syndrome (DDS), and 2/5 for ESRD after an interval of 7 and 18 years, respectively. All transplanted patients remained in CR. Another three patients developed mild renal insufficiency (creatinine levels 1.3, 1.8, and 2.8 mg/100 ml, respectively; N = 0.5-1.2), combined with hypertension in 1; neither of them was transplanted. Sixteen (64%) had normal renal function and were in CR. Long-term renal function appeared significantly better after bilateral nephron sparing surgery (NSS) then after other surgical procedures (P < 0.0001). Seven secondary tumors were found in five (20%) patients, one of whom had a DDS.

CONCLUSION

Long-term 10-year overall survival was 78%. There was significant morbidity (13/25, 52%), in terms of renal failure (8/25, 32%) including renal transplantation (5/25, 20%), and secondary tumors (5/25). These findings necessitate long-term follow-up beyond childhood. Future work should be directed at reducing the harmful effects of treatment, including the increased use of NSS.

Risk factors for end stage renal disease in non-WT1-syndromic Wilms tumor

PURPOSE

We assessed risk factors for end stage renal disease in patients with Wilms tumor without known WT1 related syndromes. We hypothesized that patients with characteristics suggestive of a WT1 etiology (early onset, stromal predominant histology, intralobar nephrogenic rests) would have a higher risk of end stage renal disease due to chronic renal failure. We predicted a high risk of end stage renal disease due to progressive bilateral Wilms tumor in patients with metachronous bilateral disease.

MATERIALS AND METHODS

End stage renal disease was ascertained in 100 of 7,950 nonsyndromic patients enrolled in a National Wilms Tumor Study during 1969 to 2002. Risk factors were evaluated with cumulative incidence curves and proportional hazard regressions.

RESULTS

The cumulative incidence of end stage renal disease due to chronic renal failure 20 years after Wilms tumor diagnosis was 0.7%. For end stage renal disease due to progressive bilateral Wilms tumor the incidence was 4.0% at 3 years after diagnosis in patients with synchronous bilateral Wilms tumor and 19.3% in those with metachronous bilateral Wilms tumor. For end stage renal disease due to chronic renal failure stromal predominant histology had a HR of 6.4 relative to mixed (95% CI 3.4, 11.9; p<0.001), intralobar rests had a HR of 5.9 relative to no rests (95% CI 2.0, 17.3; p=0.001), and Wilms tumor diagnosis at less than 24 months had a HR of 1.7 relative to 24 to 48 months and 2.8 relative to greater than 48 months (p=0.003 for trend).

CONCLUSIONS

Metachronous bilateral Wilms tumor is associated with high rates of end stage renal disease due to surgery for progressive Wilms tumor. Characteristics associated with a WT1 etiology markedly increased the risk of end stage renal disease due to chronic renal failure despite the low risk in non-WT1 syndromic cases overall.

Bilateral Wilms' tumors: single-center experience with 22 cases and literature review

OBJECTIVES

Bilateral Wilms' tumors represent a therapeutic challenge. The primary aim of management is eradication of the neoplasm and preservation of renal function. We present our experience in the management of such cases in a single-center experience.

METHODS

This was a retrospective study of 22 patients with histologically proven bilateral nephroblastoma who were treated from 1993 to 2008 at our center. Of the 22 patients, 12 were girls and 10 were boys, with a median age of 3 years (range 1-9); 19 had a synchronous presentation and 3 a metachronous presentation. Of the 22 patients, 6 underwent initial surgical resection followed by chemotherapy and 16 underwent initial biopsy and preoperative chemotherapy. The final oncologic and renal outcomes were assessed.

RESULTS

The median follow-up period was 3 years (range 1-11). Of the 22 patients, 8 died, for an overall survival rate of 63.5%. The survival for the initial chemotherapy and initial surgery groups was essentially similar. Of all the variables studied, unfavorable histologic findings had a significant negative effect on survival. Of the 5 patients with unfavorable histologic findings, 4 died during the follow-up period. The median volume of preserved renal parenchyma was 40%. All patients had good renal function during follow-up, except for 1 patient who had undergone bilateral nephrectomy.

CONCLUSIONS

Bilateral Wilms' tumors impose 2 conflicting issues: elimination of the pathology and preservation of the renal function. Currently, treatment regimens involving initial chemotherapy followed by conservative surgery can achieve these goals in an important proportion of patients.

Pediatric urologic oncology: organ-sparing surgery in kidney and testis

Technological advances in imaging as well as increased knowledge of tumor-specific biology have promoted the role of organ-sparing approaches to pediatric renal and testicular tumors. Application of these techniques continues to evolve as data on long-term follow-up become available and as protocol-guided investigation provides answers to therapeutic outcomes of these approaches. Optimally, organ-sparing surgery will continue to provide increased potential for preservation of both renal function and fertility.

Cold infusion for salvage partial hilar nephrectomy in patient with bilateral wilms tumor

We describe the use of an ice-cold solution of Ringer's lactate with additives to ameliorate ischemia-reperfusion injury and avoid renal failure in a child with bilateral Wilms tumor requiring nonanatomic, hilar resection that would leave the patient with marginal renal parenchyma postoperatively. The adequate renal function afforded by the procedure avoided the possible need for dialysis and allowed the resection area to be irradiated to prevent tumor recurrence before eventual renal transplantation.

Current management of Wilms' tumor in children

PURPOSE

Wilms' tumor is the most common renal tumor in children. Outcomes have improved dramatically over the past few decades, but important treatment questions remain. These include the role of molecular biologic markers in stratifying patients for therapy or targeting tumors for treatment. We present a summary of these advances and outline the current treatment of Wilm's tumor.

MATERIALS AND METHODS

The medical literature and results of all cooperative group studies reporting treatment of children with Wilms' tumor were reviewed.

RESULTS

Overall survival exceeds 90% for most patients with nephroblastoma. However, outcomes for patients with rhabdoid tumors and diffuse anaplasia remain poor. The role of renal sparing surgery in patients with bilateral tumors is clear, but for children with unilateral tumors it continues to be defined.

CONCLUSIONS

Current protocols conducted by pediatric oncology groups are beginning to incorporate biologic features to stratify patients for therapy. Treatment strategies continue to focus on limiting late effects of treatment while maintaining an excellent survival. New therapies are needed to treat the high-risk patients who continue to have high relapse and mortality rates.

Wilms tumour: prognostic factors, staging, therapy and late effects

Wilms tumour is the most common malignant renal tumour in children. Dramatic improvements in survival have occurred as the result of advances in anaesthetic and surgical management, irradiation and chemotherapy. Current therapies are based on trials and studies primarily conducted by large multi-institutional cooperatives including the Société Internationale d'Oncologie Pédiatrique (SIOP) and the Children's Oncology Group (COG). The primary goals are to treat patients according to well-defined risk groups in order to achieve the highest cure rates, to decrease the frequency and intensity of acute and late toxicity and to minimize the cost of therapy. The SIOP trials and studies largely focus on the issue of preoperative therapy, whereas the COG trials and studies start with primary surgery. This paper reviews prognostic factors and staging systems for Wilms tumour and its current treatment with surgery and chemotherapy. Surgery remains a crucial part of treatment for nephroblastoma, providing local primary tumour control and adequate staging and possibly controlling the metastatic spread and central vascular extension of the disease. Partial nephrectomy, when technically feasible, seems reasonable not only in those with bilateral disease but also in those with unilateral disease where the patient has urological disorders or syndromes predisposing to malignancy. Partial nephrectomy, however, is frequently not sufficient for an anaplastic variant of tumour. The late effects for Wilms tumour and its treatment are also reviewed. The treatment of Wilms tumour has been a success story, and currently in excess of 80% of children diagnosed with Wilms tumour can look forward to long-term survival, with less than 20% experiencing serious morbidity at 20 years from diagnosis. The late complications are a consequence of the type and intensity of treatment required, which in turn reflects the nature and extent of the original tumour. Continual international trial development and participation will improve matching of treatment needs with prognosis, reducing long-term complications in the majority. The advent of molecular markers of disease severity and improved functional imaging might help.

Bilateral disease and new trends in Wilms tumour

Wilms tumour is a great therapeutic success story within paediatric oncology; its prognosis is excellent. Although mainly sporadic, occurring in otherwise well children, it occurs in a small number of genetically predisposed children. Thus regular surveillance imaging is performed in predisposed children in parts of the USA and Europe. The risks and benefits of surveillance are unclear, as the existing ad-hoc surveillance protocols are lacking in consistency of practice and equity of provision. We present guidelines for Wilms tumour surveillance based on a review of current practice and available evidence, outlined by a multidisciplinary working group in the UK. Wilms tumours are bilateral in 4-13% of affected children. Bilateral synchronous nephroblastomas are observed in 5% of affected children and are usually associated with the presence of nephrogenic rests, congenital malformations and predisposing syndromes. The major challenge in bilateral disease is to achieve a cure and at the same time to preserve sufficient functional renal tissue for normal growth and development. The association among Wilms tumour, nephrogenic rests and nephroblastomatosis makes detection and characterization of renal lesions with imaging extremely important. We discuss the relative strengths and weaknesses of the different modalities used for diagnosis and follow-up in bilateral renal disease. We also discuss newly emerging diagnostic imaging tests such as (18)F-fluorodeoxyglucose positron emission tomography (FDG-PET). This technique, when fused with CT (PET-CT), allows accelerated metabolic activity to be accurately anatomically localised and so is potentially useful for staging, assessment of treatment response, and for surgical and radiotherapy planning. In addition, quantitative MRI techniques have been proved to be valuable in intracranial tumours, but no such role has been validated in abdominal disease. Diffusion-weighted imaging with calculation of ADC maps is feasible in abdominal tumours, and our own preliminary data suggest that tissue cellularity is an important determinant of ADC value, which might help in terms of early prediction of therapy response.

Renal function outcomes in patients treated with nephron sparing surgery for bilateral Wilms tumor

PURPOSE

Management of bilateral Wilms tumor represents a particular challenge in the consideration of long-term renal function for affected patients. Aggressive surgical resection to prevent recurrence must be balanced with the desire to preserve renal function. We evaluated our institutional experience with nephrological outcomes in patients treated with nephron sparing surgery for bilateral Wilms tumor.

MATERIALS AND METHODS

We identified all patients with synchronous bilateral Wilms tumors presenting to St. Jude Children's Research Hospital between October 1987 and February 2004. We also included patients with Wilms tumor involving a solitary kidney presenting during the same period. A total of 17 patients were identified who underwent nephron sparing surgery, including 16 with bilateral tumors and 1 with tumor in a solitary kidney. Institutional review board approval was obtained to retrospectively review records and analyze outcomes based on long-term renal function, hypertension, proteinuria, need for dialysis and indications for renal transplantation.

RESULTS

Eight of the 17 patients initially underwent bilateral nephron sparing surgery and 9 initially underwent a combination of nephrectomy and contralateral nephron sparing surgery. Two patients were eventually rendered anephric following further resections secondary to local recurrence. Before the initiation of therapy all patients had normal baseline creatinine clearance, which was calculated using the Schwartz formula. At a median followup from diagnosis of 72 months (range 15 to 207) 1 patient had renal insufficiency and another 3 had renal failure requiring dialysis. One of the 3 patients on dialysis died of metastatic Wilms and 2 await renal transplantation. None of the remaining patients had evidence of proteinuria. Ten of the 17 patients (58.8%) had hypertension at diagnosis and 9 (52.9%) required antihypertensive medications at the most recent followup. The overall survival rate in this group of patients was 88.2% with no evidence of disease in survivors at the most recent followup.

CONCLUSIONS

When combined with adjuvant radiation and/or chemotherapy, nephron sparing surgery provides an opportunity to preserve renal function, while maintaining excellent long-term oncological outcomes for patients with bilateral Wilms tumor.

An update on the management of Wilms' tumour

AIMS

To review the management of Wilms' tumour.

METHODS

A search of the literature was performed using the PubMed database (1966 to May 2006) with the search terms 'Wilms' and either 'tumour/tumor' or 'cancer' or 'carcinoma'. This was augmented by manual searches of publications.

FINDINGS

The success of clinical trials in Wilms' tumour patients over the past 30 years has led to an overall survival of 85% and the introduction of less aggressive chemotherapeutic regimes for patients. Large randomised controlled trials have been published on the management of Wilms' tumour by various collaborative groups, including the National Wilms' Tumour Study Group (NWTSG) in North America and the Société Internationale d'Oncologie Pédiatrique (SIOP) plus the United Kingdom Children's Cancer Study Group (UKCCSG) in Europe.

CONCLUSIONS

Controversy exists as to the best approach to the management of these children with regard to neoadjuvant chemotherapy. Challenges remain in the identification of histological and molecular risk factors for the stratification of treatment intensity.

Clinical characteristics and outcome of Wilms tumors with a favorable histology in Japan: a report from the Study Group for Pediatric Solid Malignant Tumors in the Kyushu Area, Japan

BACKGROUND/PURPOSE

Since 1996, the standard treatment of Wilms tumors in Japan has been based on the regimen of the Japanese Wilms Tumor Study. However, in Japan, there have been no reports about Wilms tumors that analyzed the clinical features and patient outcome in a large series until now. This study aims to assess the clinical characteristics of patients with Wilms tumor with a favorable histology from a retrospective standpoint in the Kyushu area in Japan and, furthermore, to analyze the historical changes of clinical features and outcome from the 1980s to the 1990s.

METHODS

Between 1982 and 1996, 90 cases of Wilms tumors with a favorable histology were registered in the Kyushu area. Regarding the clinical feature and outcome, they were divided into 2 groups (group A, 1982-1989, n = 50; group B, 1990-1996, n = 40). The outcome was analyzed based on the 5-year overall survival rate.

RESULTS

The clinical features (age, sex, initial symptom, location, stage) demonstrated no definite differences between group A and group B. Regarding the operation, the rate of an initial complete resection in the early stages was significantly higher in group B than in group A. All stage V cases in group B undewent a bilateral tumor biopsy instead of a radical nephrectomy as the initial operation. The 5-year overall survival rate throughout the whole period was 87.8%, whereas the rates were 84.0% for group A and 90.0% for group B (P = NS), respectively. Of particular note, the outcome of patients with stage I and stage V in group B substantially improved in comparison to that in group A. However, in advanced cases, no significant improvement in the outcome was noted.

CONCLUSIONS

This is the first report about the clinical features and outcome for Wilms tumors with a favorable histology in Japan from the 1980s to the 1990s. The present study suggested that in the early-stage cases, an initially complete resection followed by standard postoperative chemotherapy substantially improved the outcome of the patients in group B. In the stage V cases, the performance of renal salvage surgery may have positively contributed to the improvement in the outcome in group B. However, in the advanced stage cases, no definite improvement was noted. In the future, an improved efficacy of the treatments for Wilms tumors based on the standard protocol established by the Japanese Wilms Tumor Study in 1996 is expected in Japan.

Predictors of surgical outcome in Wilms' tumor: a single-institution comparative experience

BACKGROUND

The merits of primary nephrectomy (PN) vs preoperative chemotherapy (PC) for patients with Wilms' tumor (WT) are much debated. Early data from the International Society of Pediatric Oncology suggested decreased intraoperative spillage but increased risk of local recurrence after PC. Patients with WT at our institution were managed with PC until 1996; subsequently, they underwent PN. This study compares these approaches as they affect tumor spillage, local recurrence, and survival.

METHODS

Patients with WT diagnosed at the Hospital for Sick Children from 1985 to 2003 were reviewed.

RESULTS

One hundred sixty patients were identified (114 PC and 46 PN). Tumor spill occurred in 6 (5.3%) of 114 PC and 2 (4.3%) of 46 PN patients. Tumor inhomogeneity, tumor size, and inferior vena cava compression/clot at diagnosis did not affect incidence of spill. Of 6 PC patients with surgical spill, 1 (17%) had significant tumor shrinkage, compared with 87 (81%) of 108 without spill (P < .001). Preoperative chemotherapy and PN had equal rates of surgical complications. Preoperative chemotherapy resulted in 12 (10.5%) of 114 local recurrences vs 5 (10.8%) of 46 with PN. Event-free survival and overall survival were 80% and 92% for PC at 129 months vs 85% and 96% for PN at 61 months.

CONCLUSIONS

Preoperative chemotherapy and PN are equally effective in the treatment of WT with no difference in tumor spillage. Failure of the tumor to shrink in size with PC was significantly associated with an increase in tumor spillage and would suggest that a more cautious surgical approach be undertaken in these cases.