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

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.

[Is nephron-sparing surgery relevant for unilateral Wilms tumors?]

BACKGROUND

Wilms tumors (WTs) are the most frequent renal tumors in children. Radical nephrectomy (RN) remains the gold-standard surgical treatment for this type of cancer. Excellent results in overall survival (>90%) make it possible to consider nephronic preservation. The objective of this systematic review is to evaluate the relevance of nephron-sparing surgery (NSS) for the treatment of nonsyndromic unilateral Wilms tumor (UWT) in children.

METHODS

Articles in English related to "unilateral Wilms tumor, unilateral nephroblastoma, partial nephrectomy, nephron-sparing surgery, renal function" identified in the Medline library were screened and data were extracted to perform a qualitative systematic review.

RESULTS

We identified 377 articles, 14 of which were integrated into the analysis. Data on 4288 children were included, 3994 (93.1%) underwent RN, whereas 294 (6.8%) underwent NSS. Stage I anatomopathology resulted in 55.1% RN and 79% NSS. Overall survival and event-free survival were similar: respectively 95.7% and 92.8% after RN and 96 and 90.5% after NSS. Positive margin status was higher after NSS (8.5% vs 0.5%), but tumor rupture and local tumor recurrences were similar. The rate of mild to moderate renal function was higher after RN (42% vs 10% after NSS).

DISCUSSION

NSS is regularly performed for WT in case of bilateral or syndromic tumors, but the literature considering UWT does not show consensus. The superiority of NSS for renal outcomes has now been fully evaluated, but the main problem of this surgery in case of UWT is to ensure oncologic outcomes as good as outcomes after RN. WTs are usually massive tumors for which partial nephrectomy is contraindicated, but studies showed that chemotherapy before surgery could reduce tumor volume and make NSS possible. This review shows that NSS results seem to be as good as RN results and that preoperative chemotherapy should be highlighted for its participation in the reduction of the positive margin status. Although radiotherapy is used with caution because of its side effects, some studies showed that it gave excellent results for oncologic salvage after local recurrence. Constant progress in medical imaging and detection systems has led to the emergence of a new type of assistance for surgeons such as image reconstruction and vessel or urinary tract system segmentation. Virtual simulation of the operation based on a real case should help evaluate the feasibility of complex procedures in the near future.

CONCLUSION

NSS for UWT seems to be a credible therapeutic alternative. New technologies such as 3D reconstruction should help surgeons define the best parameters to select ideal tumors for this surgery in the near future. For the moment, small tumors (<4cm), distant from the renal hilum (ideally on the upper pole) that respect at least 50% of the renal parenchyma (ideally superficial with exophytic development) seem to be the perfect indication for NSS.

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.

Nephron-sparing surgery in bilateral Wilms' tumor: A report of two cases

Nephron-sparing surgery (NSS) has been proposed by many as an alternative to bilateral nephrectomies and renal replacement therapy in bilateral Wilms’ tumor (BWT). NSS is not without significant recurrence, morbidity, and mortality. Long-term follow-up, especially with regard to the renal function, remains lacking. Preoperative computed tomography angiogram can help prepare a roadmap for NSS but can underestimate the salvageable parenchyma due to compression of normal adjacent parenchyma. Intraoperative ultrasound can delineate the boundary of surgical margin and help achieve negative margins. We present two cases of BWT, aged 7 and 13 months, managed with neoadjuvant chemotherapy followed by bilateral NSS and adjuvant chemotherapy and report the follow-up of the same. We also explore the role of preoperative imaging and intraoperative ultrasound in the management. Both patients are alive without recurrence at a follow-up of 12 and 8 months.

Comprehensive renal function evaluation in patients treated for synchronous bilateral Wilms tumor

OBJECTIVES

The purpose of this study was to perform a comprehensive assessment of long-term renal function in patients treated at our institution for synchronous bilateral Wilms tumor (BWT) and to determine the optimal method for estimating glomerular filtration rate (eGFR).

METHODS

Surgical approach, adjuvant therapy, and pathology reports were reviewed for patients with at least six months follow-up from definitive surgery. eGFRs, as assessed by the Schwartz and Chronic Kidney Disease in Children (CKiD) formulas, were compared to measured GFR (mGFR) determined by ^99mTc-DTPA scanning. Urine studies, including microalbumin, β-microglobulin, and FE_Na were also reviewed.

RESULTS

Forty-two patients were identified. Of 36 living patients, 28 (77.8%) had greater than 6months follow-up, with a median overall follow-up of 5.2years (range: 1.4-13.4). The median mGFR was 97mL/min/1.73m², while the median eGFR_Schwartz and eGFR_CKiD were 103.3mL/min/1.73m² and 79.7mL/min/1.73m², respectively, (p=0.13 and p=0.75, compared to mGFR). Eleven (39.3%) patients had at least one abnormal urine study (microalbumin >30μg/g creatinine, n=3; β-2 microglobulin >133μg/g creatinine, n=9; FE_Na>1%, n=4).

CONCLUSIONS

In our series, few patients had an abnormally low GFR. Neither method for estimating GFR gave a significantly different result from measured GFR, suggesting that the Schwartz equation is adequate, although specific urine tests may be more sensitive for detecting subtle renal dysfunction.

LEVEL OF EVIDENCE

Level IV - retrospective case series with no comparison group.

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.

Renal function in patients with Wilms tumor

Survival in patients with Wilms tumor (WT) is excellent compared with other pediatric malignancies and adult renal tumors. Treatment-related long-term morbidity and mortality in WT survivors is an area of increasing concern. Renal dysfunction is an example of one of the most feared long-term issues observed in these survivors. Direct toxicity from chemotherapy and radiation as well as direct nephron ablation from surgical treatment (nephrectomy) renders the kidney susceptible to a multitude of problems over time in patients with WT. In this article, we review the existing literature pertaining to renal function in these patients. Incidence rates, causes, and methods to mitigate renal dysfunction are presented in 3 distinct clinical situations: sporadic unilateral WT, syndromic unilateral WT, and bilateral WT. We also offer a critical lens on the current role of nephron-sparing surgery as a means to preserve renal function in these patients. Finally, we discuss potential avenues for refining renal function preservation in patients with WT in the future. We conclude that: (1) renal function in pediatric cancer survivors must be carefully ascertained prospectively using methods that allow diagnosis of mild cases (rather than focus solely on extreme cases represented by the development of end-stage renal disease), (2) every effort should be made to recognize subtle features of predisposition syndromes to avoid syndromic cases from being misclassified and treated as sporadic, (3) molecular stratification for disease aggressiveness as well as multifocality and renal dysfunction will be very important to tailor treatment and balance survival with preservation of renal function, and (4) the role and potential benefits of nephron-sparing surgery deserves careful exploration under well-designed protocols.

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.

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.

NEPHRON-SPARING SURGERY FOR BILATERAL WILMS TUMOR

Synchronous bilateral disease occurs in approximately 5 % of children with Wilms tumor (WT), and is independently associated with an increased risk of renal insufficiency. Nephron-sparing surgery (NSS) allows preservation of renal mass and improved renal function. Published oncologic and functional outcomes with NSS to date are generally good, likely reflecting proper patient selection and excellent surgical technique during tumor excision, as well as appropriate use of upfront and adjuvant therapies. Here we highlight important issues regarding the use of NSS in children with bilateral Wilms tumor (BWT).

The initial experience with RENAL Nephrometry in children, adolescents, and young adults with renal tumors

BACKGROUND

No standardized manner exits to objectively compare renal tumor complexity in children and adolescents. However, the RENAL Nephrometry scoring system has been recently developed in adults and shown to predict tumor complexity and correlate with clinical outcomes. Thus, the study objective was to evaluate RENAL Nephrometry tumor score in a population of children, adolescents, and young adults and correlate it with tumor features and pathology.

METHODS

Patients at the study institution who underwent attempted renal tumor resection from 2002 to 2012, and had pre-operative imaging available for scoring were retrospectively reviewed. A Nephrometry score for each affected kidney was calculated separately by two blinded reviewers and the final score was based on consensus review. Tumor characteristics and oncologic outcomes were compared between the low-, moderate-, and high-complexity masses.

RESULTS

Sixty-five patients and 67 kidneys met study criteria. This included: 5 (7.5%) low-complexity, 11 (16.4%) moderate-complexity, and 51 (76.1%) high-complexity lesions. In comparing the clinical and pathologic features between groups, it was observed that less complex masses were observed in older patients, were more commonly managed with nephron-sparing surgery, and more often represented renal cell carcinoma (RCC) and other non-Wilms tumor pathology. No statistically significant correlation was observed between tumor complexity score and blood loss, operative time, transfusion requirement, positive margins or tumor rupture.

CONCLUSION

In general, renal lesions in this population are highly complex. In its current form, RENAL Nephrometry appears most useful in evaluating tumor complexity in RCC and masses in older children and adolescents.

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.

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.

Delayed tumor resection in a 5-year-old child with bilateral Wilms tumor

We describe the case of a 5-year-old girl whose abdominal pain and distension were caused by Wilms tumor of the kidney. Because of the bilateral nature of her disease, she was spared biopsy or initial nephrectomy as part of her treatment course. Rather, she was treated presumptively for Wilms tumor based primarily on radiologic findings. Neoadjuvant chemotherapy consisting of vincristine, dactinomycin and doxorubicin was given to facilitate nephron-sparing surgery for tumor resection. Her initial chemotherapeutic course was complicated by tumor lysis syndrome manifested by elevated serum uric acid and was treated effectively with hyperhydration and alkalization of intravenous fluids. The patient's disease responded well to chemotherapy, and she underwent successful tumor excision after 12 weeks of chemotherapy. The resected tumor was identified as anaplastic Wilms tumor, illustrating that pathologic identification of Wilms tumor is possible even after multiple cycles of neoadjuvant chemotherapy and marked tumor shrinkage.

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.

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.

Laparoscopic nephron-sparing resection of synchronous Wilms tumors in a case of hyperplastic perilobar nephroblastomatosis

Diffuse hyperplastic perilobar nephroblastomatosis (DHPLN) is a rare precursor lesion of Wilms tumor (WT). Because of the increased risk to develop WT in either kidney, current management algorithms of DHPLN merit nephron-sparing strategies, beginning with chemotherapy and close radiographic monitoring into late childhood. After resolution of DHPLN, subsequent detection of a renal nodule mandates resection to exclude WT. Here, we report the case of a 4-year-old girl who developed 2 synchronous nodules in the right kidney more than 2 years after completion of therapy for DHPLN. Because of the early detection and peripheral location of these 2 nodules, laparoscopic nephron-sparing resection of each was performed using ultrasonic dissection. Both nodules were determined on pathology to be favorable histology WT with negative surgical margins. The child was placed on vincristine and actinomycin D therapy for 18 weeks.

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.