Reduction in tumor burden allowing partial nephrectomy following preoperative chemotherapy in biopsy proved Wilms tumor

Nephron-sparing surgery in nonsyndromic unilateral wilms' tumor: An insight into the ongoing surgical controversy

Background:

Unilateral Wilms' tumor (uWT) is the most common renal malignancy in the pediatric population. Although the onset of surgical intervention like radical nephrectomy (RN) has substantially reduced the mortality rate, recent evidence has raised concerns regarding several postoperative complications associated with this procedure. Nephron-sparing surgery (NSS) has been reported to avoid such postoperative complications and have high technical success rate. However, not much literature is available comparing the efficacy of RN and NSS for managing nonsyndromic uWT, which makes it less acceptable globally.

Materials and Methods and Results:

A systematic identification of the literature was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines on four academic databases: MEDLINE, Scopus, EMBASE, and CENTRAL. Out of 1017 records, 20 manuscripts including 312 patients were included in the review; 4 patients treated by the author (unpublished data) have also been included. The studies included 7 retrospective case series with no comparison group, 4 retrospective case series with comparison group, 4 retrospective series with a cursory mention of NSS in uWT, 2 case reports, 1 protocolized prospective trial with comparison group, 1 administrative database analysis with comparison group, and 1 randomized controlled study. In all, 316 patients with nonsyndromic uWT were studied. The pretherapy volumes of the WT ranged from 2.4 to 640 ml. Majority of them were administered preoperative chemotherapy. About half of the patients (n = 159) (50.3%) were Stage I tumors. Stage II, III, and IV tumors were seen in 23 (7.3%), 20 (6.3%), and 3 (1%) patients. Stage was not specified in 111 (35.1%) patients. Majority of them were “intermediate risk” WT. All these tumors were nonanaplastic. Surgical margins were reported positive in 13 (4%) patients. Overall and event-free survivals were 100% in most of the studies; only handful of relapses were noted in this systematic review.

Conclusions:

This qualitative systematic review recommends the use of NSS for nonsyndromic uWT. The procedure accounts for higher postoperative renal function and lesser incidence of hypertension as compared to the radical nephrectomy. Overall and event-free survivals are comparable or even better with NSS.

Effect of Wilms tumor histology on response to neoadjuvant chemotherapy

PURPOSE

To evaluate the association between Wilms tumor histology at diagnosis and the change in Wilms' tumor volume during preoperative chemotherapy.

METHODS

We included all the 52 patients operated for Wilms tumor at 1988-2015, who had both pathology samples and either CT or MRI-images before and after preoperative chemotherapy, available for reevaluation.

RESULTS

The median tumor volume was 586 ml (IQR 323-903) at diagnosis. The median change in tumor volume was -68% (IQR -85 to -40, p < 0.001) and the proportion of tumor necrosis 85% (IQR 24-97), after preoperative chemotherapy. There was a correlation between blastemal cell content in prechemotherapy cutting needle biopsy (CNB) sample and the reduction in tumor volume (Rho = -0.452, p = 0.002). High stromal and epithelial cell contents in CNB samples were associated with the lesser change in tumor volume (Rho = 0.279, p  =0.053 and Rho = 0.300, p = 0.038 respectively). Reduction of tumor volume and the proportion of tumor necrosis after chemotherapy were associated (Rho = -0.502, p < 0.001). The actual viable tumor volume decreased in median by 97% (IQR 65-100), and the decrease could be seen in all cellular components. In three patients, the tumor volume increased more than 10% during the preoperative chemotherapy. Two of them had anaplastic tumor in the nephrectomy specimen.

CONCLUSION

Wilms tumor total and viable tumor volumes were reduced by 68% and 97% with preoperative chemotherapy, respectively. High proportion of blastemal cells in CNB was associated with greatest decrease in Wilms tumor volume. Increase in tumor volume during preoperative chemotherapy may indicate anaplastic tumor and prolonging of preoperative therapy should be avoided.

TYPE OF STUDY

Retrospective review.

LEVEL OF EVIDENCE

Level III.

Evaluation of effect of preoperative chemotherapy on Wilms' tumor histopathology

PURPOSE

To evaluate usefulness of cutting needle biopsy (CNB) to recognize pediatric renal tumors and to predict the evolution of histology during preoperative chemotherapy of Wilms tumors.

METHODS

Ninety pediatric patients were operated for renal tumors at our institution in 1988-2015. We included all 64 patients who had undergone CNB at diagnosis and whose CNB and nephrectomy samples were available for re-evaluation.

RESULTS

The CNB was diagnostic in all 59 Wilms tumors but only in two out of five non-Wilms tumors. Anaplasia was missed by CNB in one of three with diffuse anaplasia in nephrectomy specimens. In Wilms tumors the proportions of the blastemal, stromal and epithelial components were 55% (IQR 25-85), 28% (IQR 10-58) and 2% (IQR 0-10) in CNB samples and 5% (IQR 0-64), 15% (IQR 0-50) and 15% (IQR 0-44) in the nephrectomy specimens (p-values 0.002, 0.599 and 0.005 respectively). The degree of tumor necrosis was in median 80% (IQR 21-97), after preoperative chemotherapy. The degree of tumor necrosis after chemotherapy had a positive correlation with the proportion of blastemal component (p=0.008) and a negative correlation with proportion of epithelial component in pre-chemotherapy CNB samples (p<0.001).

CONCLUSIONS

Wilms tumors are usually recognizable unlike non-Wilms tumors in CNB at diagnosis. In Wilms tumors, high blastemal cell content is associated with significant tumor necrosis during pre-operative chemotherapy. Our results do not support routine use of CNB in diagnosis of renal tumors.

TYPE OF STUDY

Retrospective review.

LEVEL OF EVIDENCE

Level III.

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.

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.

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.

Oncologic outcomes of partial versus radical nephrectomy for unilateral Wilms tumor

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

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.

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.

Nephron-sparing surgery in children with primary renal tumor: indications and results

Nephron-sparing surgery (NSS) is the treatment of choice for children with bilateral Wilms' tumor (WT), or with WT on a single kidney, or with WT and a disease of the contralateral kidney, or with benign kidney tumor. NSS is a reasonable alternative to nephrectomy in children at risk of metachronous WT, including children with genetic syndromes, children younger than 1 year of age, and children with hyperplastic nephroblastomatosis. The use of NSS in selected children with "low-risk" or stage I "intermediate-risk" WT and a normal contralateral kidney is still controversial. Available data suggest that, in children with WT, NSS does not impair the outcome and has a renal function advantage over nephrectomy.

Fine-needle aspiration biopsy in pediatric oncology patients: a review of experience with 829 patients (899 biopsies)

The authors review their 20-year (1985-2004) experience with fine-needle aspiration biopsy (FNAB) in 829 children (all but 1 younger than 18 years), from whom 899 samples were obtained. All patients presented with clinical data suggesting malignancy. The procedure followed standard methods (22- to 24-gauge needle; mean of six alcohol-fixed and/or air-dried, H&E- or Giemsa-like-stained smears/procedure; leftover clots processed as a biopsy). Interpretation of cytologic smears was performed taking into consideration the clinical, laboratory, and imaging data. Smears diagnosed as positive for malignant cells were reported in 510 samples (56.7%) (463 patients); 1.89% of the smears were found inadequate for diagnosis. Positive for malignancy cases included 467 primary tumors, 52% of which were localized to the abdomen. NMYC status was determined on neuroblastoma samples by fluorescent in situ hybridization. Overall sensitivity of the procedure was 98% (500/510 FNAB); specificity was 92.6% (463/500 FNAB); positive predictive value was 1 and negative predictive value was 0.99. All FNABs diagnosed as benign tumors or inflammatory lesions correlated with histology and/or clinical outcome. FNAB proved to be highly cost-effective, avoiding a surgical biopsy. The procedure was found to be extremely helpful when deciding on preoperative chemotherapy.

Changes in computed tomography features following preoperative chemotherapy for nephroblastoma: relation to histopathological classification

The objective of this study is to assess computed tomography (CT) changes, both volume estimates and subjective features, following preoperative chemotherapy for nephroblastoma (Wilms' tumour) in patients treated on the United Kingdom Children's Cancer Study Group Wilms' Tumour Study-3 (UKW-3) protocol and to compare CT changes and histopathological classification. Twenty-one nephroblastomas in 15 patients treated on UKW-3 were included. All patients were examined by CT before and after preoperative chemotherapy treatment. CT images were reviewed (estimated volume change and subjectively assessed features). CT changes were compared to histopathological classification. Of the 21 tumours, all five high-risk tumours decreased in volume following chemotherapy (median -79%; range -37 to -91%). The sole low-risk tumour decreased in volume by 98%. Ten intermediate-risk tumours decreased in volume (median -72%; range -6 to -98%) and five intermediate-risk tumours increased (median +110%; range +11 to +164%). None of the five high-risk tumours, compared to 15/16 intermediate or low-risk tumours, became less dense and/or more homogeneous, or virtually disappeared, following chemotherapy. Volume change following chemotherapy did not relate to histopathological risk group. Changes in subjectively assessed qualitative CT features were more strongly related to histopathological risk group.

Nephron-sparing procedures in 11 patients with Wilms' tumor

PURPOSE

In unilateral Wilms' tumor (WT), tumor nephrectomy is the standard surgical approach, whereas partial nephrectomy (PN) is controversially discussed. The aim of our retrospective study was to show that in selected cases of unilateral WT kidney-sparing operations could be a reasonable alternative to nephrectomy and to discuss the results of patients with bilateral WT treated by tumor enucleation.

MATERIALS AND METHODS

From 1981 to 1998, seven patients with unilateral nephroblastoma (four stage I, one stage III and two stage IV) had tumor resection by PN (five right side, two left side), which was planned when the tumor volume was reduced after 4 to 6 weeks of chemotherapy by at least 50%, when the tumor occupied one pole or was easily resectable, when 50% or more of the kidney tissue remained and when paraaortic lymph nodes were free by intraoperative histological examination. In four patients with bilateral WT (stage V) bilateral tumor enucleation was carried out-except in one patient in whom the contralateral kidney had to been removed because of extension of the tumor via the inferior vena cava to the right atrium. All patients ( n = 11) received pre- and postoperative chemotherapy followed by radiotherapy in four patients.

RESULTS

All patients with unilateral WT ( n = 7) are still alive and disease free (follow-up time: mean 6.6 years, range: 28 months to 11 years) with normal renal function, although two patients with secondary nephrectomy revealed creatinine clearance levels at the lower range. In six patients primary PN was performed successfully. In a stage III tumor patient (intraperitoneal metastasis, free lymph nodes), secondary nephrectomy was necessary due to renal arterial thrombosis 2 days after PN. In one stage IV tumor patient (lung metastasis, free lymph nodes), the primary resection was not far enough away from the tumor margin so that an additional slice of tissue with then tumor-free margins had to be resected. This patient evolved a local relapse 19 months after PN and had to be nephrectomised thereafter. In the group of bilateral WT patients ( n = 4), one child died 2 months after surgery during chemotherapy because of central venous line sepsis. One patient who additionally suffered from inferior vena cava tumor thrombosis extending to the right atrium making nephrectomy of the right kidney necessary developed chronic renal failure 4.7 years postoperatively. The other two stage V tumor patients have creatinine clearance levels within the normal range.

CONCLUSIONS

Kidney-sparing procedures remain the operative approach of choice in patients with bilateral WT, but bear the risk of chronic renal failure when one kidney has to be removed. PN in children with unilateral WT, carried out by an experienced surgeon, is a reasonable alternative to nephrectomy if strict guidelines such as excellent tumor response to preoperative chemotherapy and easy resectability far away from the tumor margins through healthy kidney tissue are followed. Paraaortic lymph nodes must be free of tumor invasion in order to avoid local radiotherapy. PN prevents the patient from having to have dialysis in cases of contralateral nephrectomy resulting from metachronous WT or subsequent renal trauma.

The role of biopsy in the diagnosis of renal tumors of childhood: Results of the UKCCSG Wilms tumor study 3

BACKGROUND

The United Kingdom Children's Cancer Study Group (UKCCSG) Wilms Tumor Study 3 has adopted preoperative chemotherapy for Wilms tumors (WT), but required prechemotherapy biopsy for histologic diagnosis. The aims of this review were to assess the usefulness and safety of prechemotherapy biopsy and to compare histologic features of WT before and after chemotherapy.

PROCEDURE

There were 286 eligible patients but only 241 biopsies and 226 nephrectomy case slides were submitted for panel review. The presence of different histologic components of WT before and after chemo therapy was retrospectively assessed.

RESULTS

Among the 241 cases, the biopsy material in 9 (4%) was not diagnostic, in 28 (12%) that were clinically and radiologically consistent with WT, the biopsy revealed tumors other than WT, and in the remaining 204 (85%) WT was confirmed. Of 188 WT suitable cases, blastema was found in 89% of tumors at biopsy, but in only 50% at nephrectomy; the remainder were either completely necrotic (17%) or showed only epithelial and/or stromal elements (33%). Of 182 children who had percutaneous cutting needle biopsy (PCNB), a fall in haemoglobin (20% of cases) and local pain (19%) were the most common complications. One child required emergency nephrectomy due to massive intratumoral bleeding, another had tumor rupture and subsequently died, and a third developed a needle track recurrence 8 months after the biopsy.

CONCLUSIONS

A number of renal tumors (12%) can have the correct histologic diagnosis made by PCNB. Preoperative chemo therapy markedly decrease in the number of samples with preserved blastema. The morbidity associated with PCNB is small. Needle biopsy of any renal mass prior to initiation of chemotherapy is recommended.

Wilms' tumor (nephroblastoma)

Wilms' tumor (nephroblastoma) is a subject which continues to challenge clinicians in their attempts to achieve the best survival of their patients, while minimizing morbidity. Overall survival of over 85% of all children can now be achieved using combination therapy with chemotherapy, surgery, and in some cases radiotherapy. Recent reviews of two multi-institutional, multinational trials (the International Society of Pediatric Oncology and the National Wilms' Tumor Study Group) are discussed in this article, in which their current approaches to therapy are presented. In addition to these clinical advances, the genetic and molecular features of Wilms' tumor continue to provide insight into the biology of nephroblastoma and into neoplasia in general. A recent review of these aspects of the field is provided.

Controversies in the management of Wilms' tumor

Wilms' tumor is the most common malignant renal tumor of childhood; it represents 5% to 6% of childhood cancers in the United States. The survival rate of children with Wilms' tumor has improved dramatically, partly due to large multicenter studies conducted by the National Wilms' Tumor Study Group and the International Society of Pediatric Oncology. To ensure optimal patient outcome, the surgical management of these patients must be appropriate. Controversial issues in the management of Wilms' tumor include the value of preoperative chemotherapy; whether pre-resection biopsy is indicated and if so, how this is best performed; indications for partial nephrectomy; the treatment of low-risk patients with surgery only; and the reliability of preoperative imaging to assess the contralateral kidney.

Wilms' tumor. Surgical considerations and controversies

Although the therapeutic objectives for Wilms' tumor are to maximize outcomes and minimize treatment morbidity, there are some controversial issues related to different therapeutic protocols. In this article, the authors address some of the issues such as the roles of tumor biopsy, preoperative chemotherapy, contralateral exploration, and partial nephrectomy.

Complete necrosis induced by preoperative chemotherapy in Wilms tumor as an indicator of low risk: report of the international society of paediatric oncology (SIOP) nephroblastoma trial and study 9

BACKGROUND

The SIOP Nephroblastoma therapeutic protocols include a period of preoperative chemotherapy followed by nephrectomy and a period of postoperative chemotherapy. From the outset, identification of low-risk groups has been an aim of the SIOP Nephroblastoma Trials and Studies. Now that 90% of children with Wilms tumor can be cured, attention is even more focused on the identification of patients who could benefit from less aggressive postoperative therapy, thus minimizing the morbidity and late effects associated with treatment. The prognostic implications of total necrosis in nephroblastoma after chemotherapy have not been investigated hitherto.

PROCEDURE

Between November 1, 1987 and June 30, 1993, 599 patients referred to the SIOP-9 Nephroblastoma Trial and Study were preoperatively treated and classified as stages I-IV nonanaplastic Wilms tumor.

RESULTS

Of these 599 patients, pathologic examination of the nephrectomy specimen revealed a completely necrotic Wilms tumor (CNWT) with no viable tumor remaining in 59 (10%): these comprised 37 stages I-III and 22 stage IV. Of these patients, 58 (98%) had no evidence of disease at 5 years vs. 90% for the rest of the cohort (P < 0.05). Stages I-III patients represented 63% of CNWT and had a 97% overall survival rate. The only death was related to veno-occlusive disease and occurred in a stage I patient in the month following nephrectomy. Stage IV patients represented 37% of CNWT (vs. only 10% of all other cases of unilateral nonanaplastic Wilms tumor) and had a 100% rate of survival. Children with CNWT were older (mean 59 months vs. 43 months); their tumor at diagnosis was larger and had regressed more significantly at subsequent ultrasound examination. The data also uphold the hypothesis that Wilms tumors of blastemic pattern are most aggressive, but also are extremely responsive to chemotherapy.

CONCLUSIONS

Patients with unilateral nonanaplastic WT that showed total necrosis following preoperative chemotherapy had excellent outcome and should benefit from less aggressive postoperative treatment in further trials. Other very responsive tumors, such as Wilms with <10% viable tumor, should also be assessed.

Pretreatment, ultrasound-guided cutting needle biopsies in childhood renal tumors

BACKGROUND

The current International Society of Paediatric Oncology (SIOP)-10 protocol does not allow pretreatment histological classification of low-stage renal tumors in children for fear of needle tract recurrences. The aims of this retrospective study were to evaluate the safety, sensitivity, and specificity of ultrasound-guided cutting needle biopsies (UCNB) performed at our institution in pediatric patients with renal tumors.

PROCEDURE

Of 28 pediatric patients presenting with a renal tumor between 1988 and 1996, 25 underwent biopsy with the Biopty biopsy instrument (needle diameter 1.2 mm). The preoperative biopsy and nephrectomy slides were reviewed by a SIOP reference pathologist. The patients' hospital records were reviewed and biopsy complications were noted.

RESULTS

At review of the nephrectomy slides, the diagnoses were: Wilms tumor (16 patients), with anaplasia in one case, rhabdoid tumor (2 patients), neuroblastoma (2 patients), mesoblastic nephroma (2 patients), clear cell sarcoma (1 patient), malignant teratoma (1 patient), and renal cell carcinoma (1 patient). No needle tract recurrence or other major complication was observed. The only complication was local pain at the biopsy site, which occurred in 24% (6/25) of the cases. The sensitivity of UCNB was 76% (19/25); five biopsies did not yield diagnostic material and one was not concordant. All cases of Wilms tumor were correctly diagnosed by UCNB, but only 33% (3/9) of the other tumors.

CONCLUSIONS

In all cases of Wilms tumor a correct diagnosis was made. The overall sensitivity was 76%. UCNB proved to be a safe procedure that was not associated with needle tract recurrence or other serious complications.

Pediatric renal tumors

A broad spectrum of renal tumors occurs in infants and children ranging from the benign cystic nephroma to the extremely aggressive malignant rhabdoid tumor of the kidney. A thorough understanding of these tumors is crucial to the optimal diagnosis and management of children with renal masses. The common renal tumors in infants and children are discussed and an orderly method for their evaluation is presented. Recent developments in the molecular biology of Wilms' tumor are outlined to provide insight into the origin of this tumor.

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

Synchronous bilateral Wilms' tumor accounts for 4% to 6% of all Wilms' tumors. Renal salvage procedures (partial nephrectomy and enucleation) have been recommended to conserve renal parenchyma. The objective of this study was to review the results of renal salvage operations performed in children who had bilateral neoplasms. The authors reviewed the records of 98 children enrolled in the Fourth National Wilms' Tumor Study who had synchronous bilateral tumors and underwent renal salvage procedures. One hundred thirty-four kidneys were managed with renal salvage procedures. Complete excision of gross disease was accomplished in 118 (88%) of the 134 kidneys. Local tumor recurrence in the remnant kidney or tumor bed occurred in 11 cases (8.2%). Overall, 72% of the kidneys were preserved, and the 4-year survival rate was 81.7%. The surgical morbidity after a salvage procedure was comparable to that of a complete nephrectomy in patients with unilateral Wilms' tumor. Although the incidence of positive surgical margins is worrisome, it did not invariably lead to local recurrence in the remnant kidney or the tumor bed.

Renal failure in Wilms' tumor patients: a report from the National Wilms' Tumor Study Group

This report defines the incidence and determines the etiology of renal failure (RF) in patients undergoing treatment for Wilms' tumor (WT). The database of the National Wilms' Tumor Study (NWTS) was searched to identify all children reported to have developed chronic renal failure. There were 55 patients found to have RF. Of these, 39 patients had bilateral tumors, 15 with unilateral disease and one with a WT in a solitary kidney. The median interval from diagnosis to the onset of renal failure was 21 months. The incidence of RF in bilateral WT was 16.4% for NWTS-1 & -2, 9.9% for NWTS-3, and 3.8% for NWTS-4. The incidence of RF in unilateral WT remained stable. The most common etiologies of RF were: bilateral nephrectomy for persistent or recurrent tumor (24 pts), Drash syndrome (12 pts), progressive tumor in the remaining kidney (5 pts), radiation nephritis (6 pts), and other causes (5 pts). The etiology of renal failure was not reported in three children. Children with unilateral WT and a normal contralateral kidney have a very low incidence of RF, and this review does not support a recommendation for parenchymal sparing procedures in these patients. Children with bilateral WT are at risk for the development of RF, and parenchymal sparing procedures are warranted.

Staging problems in the pre-operative chemotherapy of Wilms' tumour

OBJECTIVE

To determine the effect of the International Society of Paediatric Oncology (SIOP) Wilms' tumour protocols (pre-operative chemotherapy based on clinical and radiological findings, with no prior tumour verification by open or needle biopsy) on subsequent intra-operative tumour diagnosis and staging.

PATIENTS AND METHODS

The diagnosis and staging of possible Wilms' tumour by clinical, ultrasonographic and radiological assessment were compared with the intra-operative findings in 14 consecutive children (1-12 years of age) treated between 1989 and 1994.

RESULTS

A diagnosis of Wilms' tumour was histologically verified in 11 of 14 children. In two children, verification was not possible due to complete necrosis of the tumour following pre-operative chemotherapy. In a 12-year-old boy with an estimated stage IV disease due to a solitary lung metastasis, a renal cell carcinoma was revealed in the nephrectomy specimen while subsequent thoracotomy revealed dysmorphic but not malignant tissue. The estimated tumour stage was correct with regard to localized or metastatic disease in nine of 11 children with histologically confirmed Wilms' tumour, while in two children with an estimated stage II tumour, liver metastases were found intra-operatively and the tumour was upstaged to IV.

CONCLUSION

Exact tumour diagnosis and staging was difficult in these patients. Although the accuracy of tumour staging depends on the sensitivity of radiological and ultrasonographic examinations, difficulties in tumour diagnosis may be overcome by biopsies of the primary tumour. The justification of upstaging a low-stage I/II tumour to stage III, provoking a more intense post-operative treatment, should be proven by prospective randomized studies. The decision to perform a primary tumour biopsy would be facilitated if possible subsequent deterioration of outcome could be excluded.

Partial nephrectomy in well-responding stage I Wilms' tumors: report of three cases

We report on 3 of 21 stage I Wilms' tumor patients with tumor volumes of 190, 890, and 1300 mL, respectively, who responded dramatically to preoperative chemotherapy according to the Austrian/Hungarian Wilms' Tumor Study 89 by tumor volume reductions to 20%, 23%, and 13%, respectively. Radical resection of the tumors with renal preservation was achieved in all patients. Postoperative studies did not show any functional deficit in the preserved kidney. The patients have been in complete remission for 26, 33, and 60 months, respectively. Our preliminary results indicate that tumor resection should be feasible in patients with good responding stage I Wilms' tumors.

Current management of Wilms' tumor

Most children with Wilms' tumor can now expect remarkably good survival. Current protocols have placed greater emphasis on reducing the morbidity of treatment for low-risk patients reserving intensive treatment for selected high-risk patients. This review addresses recent advances and current recommendations for the treatment of nephroblastoma. Controversial issues regarding the surgical management of these children are also discussed.

Effectiveness of preoperative chemotherapy in the treatment of Wilms tumor with vena caval and intracardiac extension

Surgical treatment of Wilms tumor with vena caval and intracardiac extension is challenging, often requiring cardiopulmonary bypass. We report the response to preoperative chemotherapy in 3 patients following a protocol at our hospital. The tumor thrombus was limited to the inferior vena cava in 2 patients and extended to the right atrium in 1. All 3 patients had marked reduction or complete eradication of the venous thrombus, facilitating the final surgical procedure. The patients are disease-free 18 months to 7 years after the initial treatment. Our protocol involves initial radiographic staging followed by needle biopsy, chemotherapy, repeat radiographic staging, definitive resection and additional chemotherapy. Our results confirm the effectiveness of this approach, which appears to decrease morbidity associated with intracaval and intra-atrial tumor extension.

Bilateral Wilms tumor. Review of outcome, associated abnormalities, and late effects in 36 pediatric patients treated at a single institution

BACKGROUND

Patients with bilateral Wilms tumor have an increased incidence of associated abnormalities and nephrogenic rests and require individualized multimodality therapy for cure. The authors reported the associated abnormalities, outcome, complications, and late effects of treatment in a group of children with bilateral Wilms tumor treated at St. Jude Children's Research Hospital, Memphis, Tennessee, over a 28-year period.

METHODS

The records of 36 consecutive pediatric patients diagnosed with bilateral Wilms tumor between 1962-1990 were analyzed. Biopsy material was also reviewed, with particular emphasis on characterization of nephrogenic rests and histology.

RESULTS

Twenty-nine patients had synchronous tumors and 7 had metachronous lesions. Associated physical abnormalities were present in 12 patients and involved the genitourinary, cardiovascular, integumentary, and musculoskeletal systems. The overall survival for patients with metachronous tumors (71%) was similar to that for those with synchronous tumors (70%). There was no effect of age or the presence of nephroblastomatosis. Two patients with synchronous tumors initially treated with nephrectomy eventually required bilateral nephrectomies for contralateral recurrence after chemotherapy and radiation therapy. Nephrogenic rests were present in 22 of 30 evaluable patients. Two of three patients with metachronous tumors had intralobar nephrogenic rests. Bilateral renal salvage procedures were demonstrated to be technically feasible and effective in controlling disease without compromising renal function or survival. Late effects included scoliosis in three patients treated before 1970, cardiomyopathy in one patient who received 300 mg/m2 doxorubicin and 12 Gy pulmonary irradiation, and benign tumors in two patients, one of whom also had a bowel obstruction. Serum creatinine, urea nitrogen, and blood pressure were normal in 23 of 26 survivors.

CONCLUSIONS

The authors' experience supports a favorable outcome with minimal late effects for patients with bilateral Wilms tumor who receive individualized therapy at pediatric oncology centers.

Unresectable stage IV nephroblastoma: a potential indication for fine-needle aspiration biopsy in children

In the United States, the initial morphologic diagnosis of nephroblastoma is usually determined on a nephrectomy specimen prior to the initiation of any additional therapy. Such an approach, however, is not appropriate in all children; we believe that fine-needle aspiration biopsies (FNAB) should be the initial diagnostic procedure in a minority of patients with suspected Wilms' tumor. One such group of patients is those who present with stage IV disease, especially when it is considered unresectable. Herein we present two children with advanced Wilms' tumor to support our contention. The initial microscopic diagnosis in each was made by FNAB. Following chemotherapy, predominantly necrotic Wilms' tumors were excised. Both patients are alive with no evidence of residual disease or untoward affects from the aspiration procedure.

Primary renal sarcoma in adults. A natural history and management study by the American Cancer Society, Illinois Division

BACKGROUND

Primary renal sarcomas in adults are rare and unusual neoplasms. This study was performed to better define the natural history and current management of these sarcomas in a typical medical setting in the United States.

METHODS

The hospital records of 4018 adult patients with renal neoplasms treated in the state of Illinois from 1975 to 1985 were examined by American Cancer Society professional volunteers.

RESULTS

A primary renal sarcoma occurred in 34 patients (0.8% incidence). Eleven adult patients had Wilms tumor, 21 had primary renal sarcoma (47% leiomyosarcoma), and 2 were not found to have sarcoma on review. The median age of the patients with Wilms tumor was 30 years, whereas that of the patients with non-Wilms sarcoma was 65 years. Four of the patients with Wilms tumor (36%) are long-term survivors and all received adjuvant chemotherapy after radical nephrectomy. Six of the patients with non-Wilms sarcoma (29%) are long-term survivors after radical nephrectomy alone.

CONCLUSIONS

Primary renal sarcomas, when treated with radical nephrectomy and, in the case of Wilms tumor, adjuvant chemotherapy, appear to be curable in 29-36% of cases. Histologic review of patients younger than 40 years of age with renal neoplasia is recommended.