Clinical impact of histologic subtypes in localized non-anaplastic nephroblastoma treated according to the trial and study SIOP-9/GPOH

Treatment of children with favorable histology Wilms tumor with extrapulmonary metastases: A report from the COG studies AREN0533 and AREN03B2 and NWTSG study NWTS-5

BACKGROUND

Patients with stage IV favorable histology Wilms tumor (FHWT) with extrapulmonary metastases (EPM) constitute a small subset of patients with FHWT. Because of their rarity and heterogeneity, optimal FHWT treatment is not well understood. Children's Oncology Group protocol AREN0533 assigned patients with FHWT and EPM to intensified chemotherapy, regimen M, after initial DD-4A chemotherapy. To improve understanding of prognostic factors and best therapies, experiences of patients with EPM on AREN0533, as well as on protocols AREN03B2 and NWTS-5, were reviewed.

METHODS

Combined outcomes for patients with EPM from NWTS-5, AREN0533, and AREN03B2 were determined. Those treated on AREN0533 were compared with those treated on NWTS-5. Prognostic factors were explored in the pooled cohort.

RESULTS

Forty-seven patients with FHWT with EPM enrolled on AREN0533, 37 enrolled on NWTS-5, and 64 were followed only on AREN03B2. The pooled cohort of all 148 patients demonstrated a 4-year event-free survival (EFS) of 77.3% (95% CI, 70.8-84.4) and 4-year overall survival of 88.9% (95% CI, 83.9-94.2). Four-year EFS of patients with EPM treated on AREN0533 was 76.0% (95% CI, 64.6-89.4) vs 64.9% (95% CI, 51.7-82.2) on NWTS-5; hazard ratio, 0.64, p = .26; no difference in overall survival was observed. Increasing linear age and slow incomplete lung response were associated with worse EFS in a pooled cohort.

CONCLUSIONS

Outcomes for patients with EPM are among the lowest for children with FHWT. Further trials with standardized surgical and radiation treatment to metastatic sites, and prospectively collected biologic and treatment details are needed.

CLINICAL TRIAL REGISTRATION

Clinical Trials.gov identifiers: NCT00379340, NCT00898365, and NCT00002611.

High Expression of WT1 and Low Expression of p53 in Archived Blocks of Children with Wilms Tumor in South Western Uganda

Purpose

The determination of the presence or absence of anaplasia in Wilms tumor is difficult sometimes creating diagnostic errors and is worsened by the use of neoadjuvant chemotherapy, which causes cellular alterations that may mimic anaplasia. This study described the histological features of Wilms tumor and their association with WT1 and p53 expression in archived specimens in South Western Uganda.

Patients and Methods

A series of 308 formalin-fixed paraffin-embedded tissue blocks belonging to 85 children were retrospectively recruited in the only public Histopathology laboratory in South Western Uganda. Rabbit monoclonal Anti-Wilms tumor protein antibody [(CAN-R9) IHC-56-2] ab89901 and rabbit monoclonal Anti-p53 antibody [E26] ab32389 were used to assess the expression of WT1 and p53, respectively. The expression of WT1 and p53 were reported as proportions, Chi-square was also performed to assess for associations and statistical significance was considered when the p-value was less than 0.05.

Results

The median age was 3.5 with an interquartile range of (2-6) years. Mixed histology was the most common at 35.29% (95% CI:25.77-46.14). Anaplasia was present in 5.88% (95% CI:2.44-13.52) of the specimens. p53 and WT1 expressions were 13.0% (95% CI:7.25-22.04), and 41.0% (95% CI: 31.11-52.04), respectively.

Conclusion

Mixed-type histology is the most common histologic feature of Wilms tumor with high expression of WT1 and a low expression of p53 implying that these can be used routinely to confirm the diagnosis as well as anaplasia in South Western Uganda.

Omission of adjuvant chemotherapy in patients with completely necrotic Wilms tumor stage I and radiotherapy in stage III: The 30-year SIOP-RTSG experience

BACKGROUND

Completely necrotic Wilms tumor (CN-WT) following preoperative chemotherapy has been regarded as low-risk WT since the International Society of Paediatric Oncology (SIOP) 93-01 study, and patients have been treated with reduced postoperative therapy. The aim of the study was to evaluate whether the omission of adjuvant chemotherapy in patients with localized CN-WT stage I and radiotherapy in stage III was safe.

PATIENTS AND METHODS

The retrospective observational study of outcomes of patients diagnosed with localized CN-WT on central pathology review and treated according to the SIOP 93-01 and SIOP-WT-2001 protocols (1993-2022).

RESULTS

There were 125 patients with localized CN-WT: 90 with stage I, 10 with stage II, and 25 with stage III. Sixty-two of 125 (49.6%) patients had a discrepant diagnosis and/or staging between the institutional pathologist and central pathology review. In the group of 90 patients with stage I, postoperative chemotherapy was not given to 41 (46%) patients, whereas 49 patients received postoperative chemotherapy-in the latter group, two patients relapsed, and one of them died. One stage I and one stage II patient developed chemotherapy-induced toxicity and died. Nineteen of 25 patients with stage III received no flank radiotherapy. No stage III patient relapsed or died. The overall 5-year event-free survival (EFS) estimate for the entire cohort (stages I-III) was 96.8% [95% confidence interval, CI: 93.6%-99.6%] and the overall survival (OS) was 97.6% [95% CI: 95.0-100%]. The EFS and OS were 97% and 98%, respectively, for stage I, and 100% for stage III.

CONCLUSION

Omission of postoperative chemotherapy for patients with CN-WT stage I, and radiotherapy for stage III is safe. Rapid central pathology review is required to assign appropriate treatment and avoid treatment-related side effects.

Hallmark discoveries in the biology of Wilms tumour

The modern study of Wilms tumour was prompted nearly 50 years ago, when Alfred Knudson proposed the 'two-hit' model of tumour development. Since then, the efforts of researchers worldwide have substantially expanded our knowledge of Wilms tumour biology, including major advances in genetics - from cloning the first Wilms tumour gene to high-throughput studies that have revealed the genetic landscape of this tumour. These discoveries improve understanding of the embryonal origin of Wilms tumour, familial occurrences and associated syndromic conditions. Many efforts have been made to find and clinically apply prognostic biomarkers to Wilms tumour, for which outcomes are generally favourable, but treatment of some affected individuals remains challenging. Challenges are also posed by the intratumoural heterogeneity of biomarkers. Furthermore, preclinical models of Wilms tumour, from cell lines to organoid cultures, have evolved. Despite these many achievements, much still remains to be discovered: further molecular understanding of relapse in Wilms tumour and of the multiple origins of bilateral Wilms tumour are two examples of areas under active investigation. International collaboration, especially when large tumour series are required to obtain robust data, will help to answer some of the remaining unresolved questions.

Grossing to reporting of Wilms tumor with emphasis on proper sampling in treatment-naive and postchemotherapy specimens and their clinicopathological correlation with outcome

Context

Emphasis on grossing to reporting for the assessment of histopathological parameters predicting outcomes in Wilms tumor.

Aims

To analyze various clinicopathological parameters that effect outcomes in treatment naïve and post chemotherapy Wilms tumor specimens.

Settings and Design

This was a retrospective observational study.

Subjects and Methods

All patients diagnosed with Wilms tumor between 2012 and 2018 at our institute will be included with their clinical findings, laboratory reports, and radiological findings. The patients will be categorized into two groups based on treatment protocol (Society of Pediatric Oncology (SIOP) or the National Wilms Tumor Study Group/Children's Oncology Group (COG) guidelines) used. Details of Grossing and reporting protocols used for the in pre treatment and post treatment specimens will be analyzed. Follow-up till December 2020 will be analyzed.

Statistical Analysis Used

Chi-square and Fisher's exact tests were used for statistical analysis.

Results

A total of 36 patients with the diagnosis of Wilms tumor were included in the present study. The mean age of presentation was 3.9 ± 0.7 years, and males were more common than females. Most of them presented as abdominal mass and few with isolated hematuria. Twenty-six (72%) patients were treated under SIOP protocol with preoperative neoadjuvant chemotherapy. Ten patients underwent upfront surgery as per COG protocol. In SIOP group patients, the mean tumor size was 9.3cm. Forty percent (n = 10) we mixed histological type followed by blastemal type constituting (32%, n = 8). Regressive and epithelial histological types constituted 16% (n = 4) and 12% (n = 3), respectively. In the SIOP group 72% (n = 19) had no anaplasia and 28% (n = 7) had anaplasia. Fifty seven percent (n = 15) cases were Stage I, followed by 26.9% n = 7) and 11.5% (n = 3) being Stage II and Stage III, respectively. Ten patients underwent upfront surgery as per COG protocol. The mean tumor size among this group was 8 cm ranging from 7 cm to 11 cm. Eight (80%) cases had favorable histology and two cases showed focal anaplasia. Heterologous differentiation is seen in 3 (70%). Out of the 10 cases, one case was Stage I, six were Stage 2, one was Stage III, and two were clinical Stage IV. None of the cases showed either vessel or lymph node metastasis. All the patients received adjuvant chemotherapy postsurgery and were followed up till December 2020 for (at least 3 years). Of 25 patients in the SIOP group, 18 (72%) had complete remission with no radiological evidence of residual disease. Of the 10 patients in the COG group, 6 (70%) had complete remission.

Conclusions

Histopathological evaluation of Wilms tumor is a critical aspect in the management of Wilms tumor, as tumor characteristics are different in the tumors treated under SIOP and COG protocols, which will ultimately affect the prognostic risk stratification. This necessitates the knowledge of the important grossing and reporting of these tumors under the two protocols.

The tumor microenvironment and immune targeting therapy in pediatric renal tumors

This review highlights the role of several immunomodulating elements contributing to the tumor microenvironment of various pediatric renal tumors including Wilms tumor. The roles of innate and adaptive immune cells in renal tumors are summarized as well as immunomodulatory cytokines and other proteins. The expression and the predictive role of checkpoint modulators like PD-L1 and immunomodulating proteins like glypican-3, B7-H3, COX-2 are highlighted with a translational view toward potential therapeutic innovations. We further discuss the current state of preclinical models in advancing this field of study. Finally, examples of clinical trials of immunomodulating strategies such as monoclonal antibodies and chimeric antigen receptor T (CAR-T) cells for relapsed/refractory/progressive pediatric renal tumors are described.

Postchemotherapy tumor volume as a prognostic indicator in Wilms tumor: A single-center experience from South India

BACKGROUND

Optimal risk stratification is the key to minimizing relapse and toxicity in children with Wilms tumor (WT). The study evaluated poor tumor volume response to chemotherapy as a risk factor that predicts relapse.

PROCEDURE

Children with WT who were treated between 2005 and 2020 at the center were analyzed. Tumor volumes at the time of diagnosis and after preoperative chemotherapy were calculated from cross-sectional imaging. The International Society of Paediatric Oncology (SIOP)-WT-2001 protocol was used for treatment. The area under a receiver operating characteristic curve was estimated to ascertain the ability of tumor volume to predict relapse.

RESULTS

Ninety-five patients with a median age of 40 months were included. A postchemotherapy tumor volume cutoff of 270 ml was ascertained to have the best predictive value for relapse. Patients with a tumor volume of <270 ml following preoperative chemotherapy had a better 3-year event-free survival (EFS) than those with a tumor volume of ≥270 ml (89.8% ± 4.0% vs. 57.4% ± 12.5%, p = .001). The data demonstrated that a tumor volume of ≥270 ml after chemotherapy was associated with an increased risk of relapse (hazard ratio [HR]: 5.3, p = .006). The EFS in patients with an epithelial or stromal type of histopathology was not affected by the tumor volume response (p = .437). Conversely, patients with other types of intermediate-risk histopathology who had a poor tumor volume response had an inferior survival (3-year EFS 51.4% ± 18.7%, p = .001).

CONCLUSION

A postchemotherapy tumor volume cutoff of ≥270 ml emerged as a strong predictor of relapse in a low- and middle-income country (LMIC) center study of WT treated with the SIOP protocol.

Prognostic Factors for Wilms Tumor Recurrence: A Review of the Literature

Simple Summary

A Wilms tumor is a childhood kidney tumor. In high-income countries, 90% of patients with this tumor survive. However, the tumor recurs in 15% of patients. It is important to identify the patients at risk of recurrence in order to adjust treatment in such a way that recurrence may potentially be prevented. However, we are currently unable to determine precisely which patients are at risk of recurrence. Therefore, we present an overview of factors that influence the risk of recurrence, also known as prognostic factors. These factors range from patient-, tumor- and treatment-related characteristics to geographic and socioeconomic factors. In addition to these factors, biological markers, such as genetic alterations, should be studied more intensively as these markers may be able to better identify patients at risk of tumor recurrence.

Abstract

In high-income countries, the overall survival of children with Wilms tumors (WT) is ~90%. However, overall, 15% of patients experience tumor recurrence. The adverse prognostic factors currently used for risk stratification (advanced stage, high risk histology, and combined loss of heterozygosity at 1p and 16q in chemotherapy-naïve WTs) are present in only one third of these cases, and the significance of these factors is prone to change with advancing knowledge and improved treatment regimens. Therefore, we present a comprehensive, updated overview of the published prognostic variables for WT recurrence, ranging from patient-, tumor- and treatment-related characteristics to geographic and socioeconomic factors. Improved first-line treatment regimens based on clinicopathological characteristics and advancing knowledge on copy number variations unveil the importance of further investigating the significance of biological markers for WT recurrence in international collaborations.

Prognostic significance of histopathological response to preoperative chemotherapy in unilateral Wilms' tumor: An analysis of 899 patients treated on the SIOP WT 2001 protocol in the UK-CCLG and GPOH studies

In the SIOP Wilms' tumor (WT) studies, preoperative chemotherapy is used as primary treatment, and tumors are classified thereafter by pathologists. Completely necrotic WTs (CN-WTs) are classified as low-risk tumors. The aim of the study was to evaluate whether a subset of regressive type WTs (RT-WTs) (67%-99% chemotherapy-induced changes [CIC]) showing an exceptionally good response to preoperative chemotherapy had comparably excellent survivals as CN-WTs, and to establish a cut-off point of CIC that could define this subset. The study included 2117 patients with unilateral, nonanaplastic WTs from the UK-CCLG and GPOH-WT studies (2001-2020) treated according to the SIOP-WT-2001 protocol. There were 126 patients with CN-WTs and 773 with RT-WTs, stages I-IV. RT-WTs were subdivided into subtotally necrotic WTs (>95% CIC) (STN-WT96-99) (124 patients) and the remaining of RT-WT (RR-WT67-95) (649 patients). The 5-year event-free survival (EFS) and overall survival (OS) for CN-WTs were 95.3% (±2.1% SE) and 97.3% (±1.5% SE), and for RT-WTs 85.7% (±1.14% SE, P < .01) and 95.2% (±0.01% SE, P = .59), respectively. CN-WT and STN-WT96-99 groups showed significantly better EFS than RR-WT67-95 (P = .003 and P = .02, respectively), which remained significantly superior when adjusted for age, local stage and metastasis at diagnosis, in multivariate analysis, whereas OS were superimposable (97.3 ± 1.5% SE for CN-WT; 97.8 ± 1.5% SE for STN-WT96-99; 94.7 ± 1.0% SE for RR-WT67-95). Patients with STN-WT96-99 share the same excellent EFS and OS as patients with CN-WTs, and although this was achieved by more treatment for patients with STN-WT96-99 than for patients with CN-WT, reduction in postoperative treatment of these patients may be justified.

Non-coding RNAs in Wilms' tumor: biological function, mechanism, and clinical implications

Non-coding RNAs are involved with maintenance and regulation of physiological mechanisms and are involved in pathological processes, such as cancer. Among the small ncRNAs, miRNAs are the most explored in tumorigenesis, metastasis development, and resistance to chemotherapy. These small molecules of ~ 22 nucleotides are modulated during early renal development, involved in the regulation of gene expression and Wilms' tumor progression. Wilms' tumors are embryonic tumors with few mutations and complex epigenetic dysregulation. In recent years, the small ncRNAs have been explored as potentially related both in physiological development and in the tumorigenesis of several types of cancer. Besides, genes regulated by miRNAs are related to biological pathways as PI3K, Wnt, TGF-β, and Hippo signaling pathways, among others, which may be involved with the underlying mechanisms of resistance to chemotherapy, and in this way, it has emerged as potential targets for cancer therapies, including for Wilms' tumors.

Estimated clinical benefit of combining highly conformal target volumes with Volumetric-Modulated Arc Therapy (VMAT) versus conventional flank irradiation in pediatric renal tumors

•

Recently, flank target volumes adjusted for organ shift/motion have been defined.

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Highly conformal volumes with VMAT were compared to conventional volumes/beams.

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The new approach prevented a dose constraint violation of ≥ 1 OARs in 60% of cases.

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VMAT reduced the irradiated Total Body Volume receiving > 10% of the prescribed dose.

Background

For decades, Anterior-Posterior/Posterior-Anterior (AP/PA) photon beams were standard-of-care for flank irradiation in children with renal cancer. Recently, highly conformal flank target volumes were defined correcting for postoperative organ shift and intra-fraction motion.

By radiotherapy treatment plan comparison, this study aims to estimate the clinical benefits and potential risks of combining highly conformal target volumes with Volumetric-Modulated Arc Therapy (VMAT) versus conventional target volumes with AP/PA beams for flank irradiation.

Materials and Methods

Twenty consecutive renal tumor cases (left/right-sided:10/10; median age:3.2 years) were selected. Highly conformal flank target volumes were generated for VMAT, while conventional target volumes were used for AP/PA. For each case, the dose to the organs at risk (OARs) and Total Body Volume (TBV) was calculated to compare VMAT with AP/PA treatment plans for a prescribed dose (PD) of 14.4/1.8 Gy. Dose constraint violation of the tail of the pancreas and spleen (D_mean < 10 Gy), heart (D₅₀ < 5 Gy) or mammary buds (D_mean < 10 Gy) were prioritized as potentially beneficial for clinics.

Results

Highly conformal Planning Target Volumes (PTV) were smaller than conventional volumes (mean ΔPTV_AP/PA-PTV_VMAT: 555 mL, Δ60%, p=<0.01). A mean dose reduction favoring VMAT was observed for almost all OARs. Dose constraints to the tail of the pancreas, spleen, heart and mammary buds were fulfilled in 8/20, 12/20, 16/20 and 19/20 cases with AP/PA, versus 14/20, 17/20, 20/20 and 20/20 cases with VMAT, respectively. In 12/20 cases, VMAT prevented the dose constraint violation of one or more OARs otherwise exceeded by AP/PA. VMAT increased the TBV receiving 10% of the PD, but reduced the amount of irradiated TBV for all higher doses.

Conclusion

Compared to 14.4 Gy flank irradiation using conventional AP/PA photon beams, an estimated clinical benefit by dose reduction to the OARs can be expected in 60% of the pediatric renal tumor cases using highly conformal flank target volumes combined with VMAT.

Outcome of Stage IV Completely Necrotic Wilms Tumour and Local Stage III Treated According to the SIOP 2001 Protocol

Simple Summary

Around 15–20% of all Wilms tumour (WT) patients present with metastatic disease. Approximately 10% of these patients achieve complete necrosis after preoperative chemotherapy, which is associated with a favourable prognosis. The aim of this observational study is to describe the outcome of metastatic patients with completely necrotic (low-risk histology), local stage III WT treated according to the SIOP 2001 protocol, whether or not postoperative radiotherapy was applied.

Abstract

Objective: Wilms tumour (WT) patients with a localised completely necrotic nephroblastoma after preoperative chemotherapy are a favourable outcome group. Since the introduction of the SIOP 2001 protocol, the SIOP– Renal Tumour Study Group (SIOP–RTSG) has omitted radiotherapy for such patients with low-risk, local stage III in an attempt to reduce treatment burden. However, for metastatic patients with local stage III, completely necrotic WT, the recommendations led to ambiguous use. The purpose of this descriptive study is to demonstrate the outcomes of patients with metastatic, completely necrotic and local stage III WT in relation to the application of radiotherapy or not. Methods and materials: all metastatic patients with local stage III, completely necrotic WT after 6 weeks of preoperative chemotherapy who were registered in the SIOP 2001 study were included in this analysis. The pattern of recurrence according to the usage of radiation treatment and 5 year event-free survival (EFS) and overall survival (OS) was analysed. Results: seven hundred and three metastatic WT patients were registered in the SIOP 2001 database. Of them, 47 patients had a completely necrotic, local stage III WT: 45 lung metastases (11 combined localisations), 1 liver/peritoneal, and 1 tumour thrombus in the renal vein and the inferior vena cava with bilateral pulmonary arterial embolism. Abdominal radiotherapy was administered in 29 patients (62%; 29 flank/abdominal irradiation and 9 combined with lung irradiation). Eighteen patients did not receive radiotherapy. Median follow-up was 6.6 years (range 1–151 months). Two of the 47 patients (4%) developed disease recurrence in the lung (one combined with abdominal relapse) and eventually died of the disease. Both patients had received abdominal radiotherapy, one of them combined with lung irradiation. Five-year EFS and OS were 95% and 95%, respectively. Conclusions: the outcome of patients with stage IV, local stage III, completely necrotic Wilms tumours is excellent. Our results suggest that abdominal irradiation in this patient category may not be of added value in first-line treatment, consistent with the current recommendation in the SIOP–RTSG 2016 UMBRELLA protocol.

The prognosis of prechemotherapy blastemal predominant histology subtype in Wilms tumor: A retrospective study in China

PURPOSE

This study aimed to retrospectively analyze survival outcomes for Chinese patients with prechemotherapy blastemal predominant histology type Wilms tumors (WTs).

METHODS

We collected and analyzed clinical data concerning patients aged <15 years with favorable histology (FH) WTs treated at the Sun Yat-Sen University Cancer Center from December 2005 to May 2016, based on the Children's Oncology Group protocol. Pathological specimens were collected through biopsy or surgical resection before initiation of chemotherapy. We analyzed survival outcomes involving different prechemotherapy histology subtypes.

RESULTS

We enrolled 97 patients with FH WTs (median follow-up, 71.5 months; range, 22.2-170.7). The total recurrence rate was 17.5%, and the subtype recurrence rates were as follows: blastemal predominant (45.5%), mixed (7.5%), epithelial (14.3%), and mesenchymal (9.5%) (P = .010). Five-year event-free survival (EFS) and overall survival (OS) rates were 84.9% and 81.4%, respectively. Respective 5-year EFS and OS rates for subtypes were as follows: blastemal predominant (54.5% and 68.2%), mixed (90.0% and 88.9%), epithelial (85.7% and 85.1%), and mesenchymal (90.5% and 94.7%). Multivariate survival analyses showed that the blastemal predominant subtype was an independent prognostic factor of EFS (P = .001) and OS (P = .017).

CONCLUSIONS

Our findings showed that prechemotherapy blastemal predominant WTs had higher recurrence and lower EFS and OS rates. Our findings suggested that, albeit with some deficiencies, blastemal predominant histology WT-diagnosed prechemotherapy may have prognostic relevance. Further research into other potential confounding variables are required to determine whether such patients warrant altered risk-stratified therapy.

Treatment of Wilms Tumor in Sub-Saharan Africa: Results of the Second French African Pediatric Oncology Group Study

PURPOSE

Multidisciplinary management of Wilms tumor has been defined through multicenter prospective studies and an average expected patient cure rate of 90%. In sub-Saharan Africa, such studies are uncommon. After the encouraging results of the first Groupe Franco-Africain d'Oncologie Pédiatrique (GFAOP) study, we report the results of the GFAOP-NEPHRO-02 study using an adaptation of the International Society of Paediatric Oncology 2001 protocol.

PATIENTS AND METHODS

From April 1, 2005, to March 31, 2011, seven African units participated in a nonrandomized prospective study. All patients who were referred with a clinical and radiologic diagnosis of renal tumor were screened. Those older than age 6 months and younger than 18 years with a unilateral tumor previously untreated were pre-included and received preoperative chemotherapy. Patients with unfavorable histology or with a tumor other than Wilms, or with a nonresponding stage IV tumor were excluded secondarily.

RESULTS

Three hundred thirteen patients were initially screened. Two hundred fifty-seven patients were pre-included and 169 with histologic confirmation of intermediate-risk nephroblastoma were registered in the study and administered postoperative treatment. Thirty-one percent of patients were classified as stage I, 38% stage II, 24% stage III, and 7% stage IV. Radiotherapy was not available for any stage III patients. Three-year overall survival rate was 72% for all study patients and 73% for those with localized disease.

CONCLUSION

It was possible to conduct sub-Saharan African multicenter therapeutic studies within the framework of GFAOP. Survival results were satisfactory. Improvements in procedure, data collection, and outcome are expected in a new study. Radiotherapy is needed to reduce the relapse rate in patients with stage III disease.

Absence of the TRIP13 c.1060C>T Mutation in Wilms Tumor Patients From Pakistan

BACKGROUND AND AIM

Wilms tumor (WT) is the most common childhood malignant renal tumor. Germline mutations in several WT predisposition genes have been identified. However, the fundamental cause of most WT patients remains unexplained. Recently, a founder mutation, c.1060C>T (p. Arg254X) in a mitotic spindle checkpoint gene, TRIP13, was reported in 5 unrelated children with WT from the United Kingdom, of Pakistani descent from Azad Kashmir region. This observation suggests other children with WT in Pakistan may also harbor this mutation. We conducted the first study to assess the contribution of TRIP13 c.1060C>T mutation to WT in Pakistan.

MATERIALS AND METHODS

Constitutional genomic DNA from 68 Pakistani individuals including unrelated WT cases (n=26) and one (n=10) or both (n=32) of their parent(s) were screened for the TRIP13 c.1060C>T mutation using DNA sequence analysis. We also included positive controls in the analyses.

RESULTS

The median age of WT diagnosis was 3.0 years (range, 0.75 to 10). The TRIP13 c.1060C>T mutation was not found in any WT patient (n=26) or their parents (n=42). Twenty-four patients (92.4%) presented with unilateral tumor and 2 patients (7.7%) were diagnosed with synchronous bilateral WT. Thirteen patients (50%) reported parental consanguinity. Thirteen patients (50.0%) belonged to the Punjabi ethnicity and 1 patient (3.8%) had a Kashmiri background. Four patients (16.7%) reported a family history of WT or other malignancies. The predominant histologic subtype was stromal (46.2%). The majority of patients presented with >5 cm of tumor size (81%). None of the patients had a personal or family history of congenital anomalies, or associated genetic syndromes.

CONCLUSIONS

Our findings suggest that TRIP13 c.1060C>T mutation may be infrequent in Pakistani WT cases. Further evaluation of this mutation in a large number of WT patients of Kashmiri heritage and various ethnic backgrounds from Pakistan is warranted.

Is radiotherapy required in first-line treatment of stage I diffuse anaplastic Wilms tumor? A report of SIOP-RTSG, AIEOP, JWiTS, and UKCCSG

BACKGROUND

As a significant proportion of relapses occurred in the tumor bed or abdomen on patients with the fifth National Wilms Tumor Study stage I anaplastic Wilms tumor (WT), flank radiotherapy was added for stage I anaplastic WT in the subsequent study of the Children's Oncology Group (AREN0321). Preliminary results revealed reduction of relapse rate and improved survival. In cases treated with preoperative chemotherapy, such as in International Society of Pediatric Oncology (SIOP), the value of radiotherapy has never been studied. The aim of this observational study is to describe the pattern of recurrence and survival of patients with stage I diffuse anaplastic WT (DAWT) after induction chemotherapy.

METHODS

Retrospective data analysis of the pattern of relapse and survival of all patients with stage I DAWT were included in recent SIOP, L'Associazone Italiana Ematologica Oncologia Pediatrica (AIEOP), Japan Wilms Tumor Study Group (JWiTS), United Kingdom Children's Cancer Study Group (UKCCSG) renal tumor registries. Postoperative treatment consisted of actinomycin D, vincristine, and doxorubicin for 28 weeks without local irradiation.

RESULTS

One hundred nine cases with stage I DAWT were identified, of which 95 cases received preoperative chemotherapy. Of these, seven patients underwent preoperative true-cut biopsy. Sixteen of the 95 patients relapsed (17%), six locally, four at distant site, and six combined, and all treated according to SIOP 2001 relapse protocol, which resulted in a 5-year overall survival of 93%.

CONCLUSION

Despite 13% locoregional relapse rate, an excellent rescue rate was achieved after salvage treatment, in patients with stage I DAWT whose first-line treatment comprised three-drug chemotherapy (including doxorubicin), without flank irradiation. Therefore, we continue not to advocate the use of radiotherapy in first-line treatment after preoperative chemotherapy in stage I DAWT in the next SIOP protocol.

MicroRNA Profiling in Wilms Tumor: Identification of Potential Biomarkers

Wilms tumor (WT) is the most frequently diagnosed malignant renal tumor in children. With current treatments, ~90% of children diagnosed with WT survive and generally present with tumors characterized by favorable histology (FHWT), whereas prognosis is poor for the remaining 10% of cases where the tumors are characterized by cellular diffuse anaplasia (DAWT). Relatively few studies have investigated microRNA-related epigenetic regulation and its relationship with altered gene expression in WT. Here, we aim to identify microRNAs differentially expressed in WT and describe their expression in terms of cellular anaplasia, metastasis, and association with the main genetic alterations in WT to identify potential prognostic biomarkers. Expression profiling using TaqMan low-density array was performed in a discovery cohort consisting of four DAWT and eight FHWT samples. Relative quantification resulted in the identification of 109 (48.7%) microRNAs differentially expressed in both WT types. Of these, miR-10a-5p, miR-29a-3p, miR-181a-5p, miR-200b-3p, and miR-218-5p were selected and tested by RT-qPCR on a validation cohort of 53 patient samples. MiR-29a and miR-218 showed significant differences in FHWT with low (P = 0.0018) and high (P = 0.0131) expression, respectively. To discriminate between miRNA expression FHWTs and healthy controls, the receiver operating characteristic (ROC) curves were obtained; miR-29a AUC was 0.7843. Furthermore, low expression levels of miR-29a and miR-200b (P = 0.0027 and P = 0.0248) were observed in metastatic tumors. ROC curves for miR-29a discriminated metastatic patients (AUC = 0.8529) and miR-200b (AUC = 0.7757). To confirm the differences between cases with poor prognosis, we performed in situ hybridization for three microRNAs in five DAWT and 17 FHWT samples, and only significant differences between adjacent tissues and FHWT tumors were found for miR-181a, miR-200b, and miR-218, in both total pixels and nuclear analyses. Analysis of copy number variation in genes showed that the most prevalent alterations were WTX (47%), IGF2 (21%), 1q (36%) gain, 1p36 (16%), and WTX deletion/1q duplicate (26%). The five microRNAs evaluated are involved in the Hippo signaling pathway and participate in Wilms tumor development through their effects on differentiation, proliferation, angiogenesis, and metastasis.

Imaging of Wilms tumor: an update

Wilms tumor is the most common pediatric renal tumor, accounting for approximately 7% of all childhood cancers. Imaging plays an important role in the detection, staging, post-therapy evaluation and surveillance of Wilms tumor. Wilms tumor can be detected during surveillance of a known cancer predisposition or after a child presents with symptoms. In this manuscript we describe an evidence-based approach to the initial evaluation of Wilms tumor using current guidelines from the Children's Oncology Group (COG). We illustrate the COG staging system for pediatric renal tumors and highlight key imaging findings that are critical for surgical management. We also discuss the controversies regarding detection and significance of <5-mm pulmonary nodules at initial staging. And finally, we present some thoughts regarding surveillance of Wilms tumor, where overall survival has now approached 90%.

Blastemal predominant type Wilms tumor in Japan: Japan Children's Cancer Group

BACKGROUND

Persistence of blastemal components after chemotherapy is a marker of poor outcome in Wilms tumor (WT). Recent reports from local Japanese areas have described pre-chemotherapy blastemal predominant type WT to also be a risk factor for relapse. The significance, however, of blastemal predominant WT remains to be evaluated in a larger study. This study retrospectively evaluated the prognostic significance of pre-chemotherapy blastemal predominant type WT in the Japan Wilms tumor Study (JWiTS) trials.

METHODS

The JWiTS trial (1996-2013) was a prospective, single-arm study. The outcomes of blastemal predominant type WT were retrospectively evaluated compared with non-blastemal type WT excluding anaplasia between 1996 and 2013. Relapse-free survival (RFS) and overall survival (OS) were estimated.

RESULTS

Of 319 primary renal tumors diagnosed by the central pathology review system, advanced stage of pre-chemotherapy blastemal predominant type WT (n = 53; 16.1%) occurred more frequently in older children than non-blastemal type WT (n = 225), and was especially frequent in female patients registered in the JWiTS trials. No significant difference in 10 years RFS and OS (78.8% vs 84.5; P = 0.201) or in 10 years RFS and OS (89.3% vs 93.5; P = 0.45) was seen between pre-chemotherapy blastemal predominant type and non-blastemal type WT.

CONCLUSIONS

Relapse-free survival and OS are not significantly different between pre-chemotherapy blastemal predominant type and non-blastemal type WT.

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.

The effect of preoperative chemotherapy on histological subtyping and staging of Wilms tumors: The United Kingdom Children's Cancer Study Group (UKCCSG) Wilms tumor trial 3 (UKW3) experience

BACKGROUND

Two principal approaches to Wilms tumor (WT) treatment are immediate surgery (IS) and preoperative chemotherapy (PCT), and both treatments use the risk-adapted approach that includes histological subclassification of the tumor, combined with additional prognostic factors. In the UKW3 trial, these two approaches were compared. The aim of the present study was to compare histological features between the two groups, to assess the impact of PCT on distribution of histological subtyping and staging and to evaluate whether PCT resulted in more staging discrepancies between local and central pathology review (CPR).

MATERIALS AND METHODS

The cases were identified from the UKW3 trial database. The criteria for inclusion in the study were unilateral, nonmetastatic, nonanaplastic WTs, and submitted for CPR with an adequate number of slides. They were subclassified according to the NWTS and later the SIOP 9301 criteria.

RESULTS

There were 244 WTs in the IS and 182 in the PCT group subclassified as follows: blastemal 86 (35%) vs 9 (5%), epithelial 34 (14%) vs 12 (7%), stromal 12 (5%) vs 25 (14%), mixed 112 (46%) vs 45 (25%), respectively, plus 40% regressive and 10% completely necrotic WTs in the PCT group. The differences between the two groups for blastemal and mixed types were statistically significant. In the PCT group, there was a significant decrease in stage III tumors. The discrepancies in staging between local and CPR were not significant.

CONCLUSION

PCT significantly altered histological features and typing of WTs. It resulted in fewer stage III tumors, and staging discrepancies were equally represented in both groups.

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.

Evaluation of boost irradiation in patients with intermediate-risk stage III Wilms tumour with positive lymph nodes only: Results from the SIOP-WT-2001 Registry

OBJECTIVE

To evaluate the value of radiotherapy boost omission in patients with intermediate-risk, stage III Wilms tumours (WT) with positive lymph nodes (LN).

METHODS AND MATERIALS

All patients with intermediate-risk, stage III (LN positive) WT consecutively registered in the SIOP-WT-2001 study were included in this analysis. Endpoints were 5-year event-free survival (EFS), loco-regional control (LRC) and overall survival (OS).

RESULTS

Between June 2001 and May 2015, 2,569 patients with stage I to III WT after preoperative chemotherapy were registered in the SIOP-WT-2001 study. Five hundred and twenty-three (20%) had stage III disease, of which 113 patients had stage III due to positive LN only. Of those, 101 (89%) received radiotherapy, 36 of which (36%) received, apart from flank irradiation, a boost dose to the LN positive area. Four patients (4%) did not receive any adjuvant radiotherapy. In eight patients information on radiotherapy was not available. With a median follow-up of 71 months, no difference in 5-year EFS (84% vs. 83%, P = 0.77) and LRC (96% vs. 97%, P = 0.91) was observed between patients receiving a radiotherapy boost and those without boost, respectively. Five-year OS, including salvage therapy, was excellent (boost vs. no boost: 97% vs. 95%, P = 0.58).

CONCLUSIONS

Outcome data demonstrate that omission of the radiotherapy boost to the loco-regional positive lymph nodes in patients with intermediate-risk, stage III WT who receive preoperative chemotherapy and postoperative flank irradiation (14.4 Gy) can be considered a safe approach for future SIOP protocols.

Chemotherapy and terminal skeletal muscle differentiation in WT1-mutant Wilms tumors

Wilms tumors (WT) with WT1 mutations do not respond well to preoperative chemotherapy by volume reduction, suggesting resistance to chemotherapy. The histologic pattern of this tumor subtype indicates an intrinsic mesenchymal differentiation potential. Currently, it is unknown whether cytotoxic treatments can induce a terminal differentiation state as a direct comparison of untreated and chemotherapy-treated tumor samples has not been reported so far. We conducted gene expression profiling of 11 chemotherapy and seven untreated WT1-mutant Wilms tumors and analyzed up- and down-regulated genes with bioinformatic methods. Cell culture experiments were performed from primary Wilms tumors and genetic alterations in WT1 and CTNNB1 analyzed. Chemotherapy induced MYF6 165-fold and several MYL and MYH genes more than 20-fold and repressed many genes from cell cycle process networks. Viable tumor cells could be cultivated when patients received less than 8 weeks of chemotherapy but not in two cases with longer treatments. In one case, viable cells could be extracted from a lung metastasis occurring after 6 months of intensive chemotherapy and radiation. Comparison of primary tumor and metastasis cells from the same patient revealed up-regulation of RELN and TBX2, TBX4 and TBX5 genes and down-regulation of several HOXD genes. Our analyses demonstrate that >8 weeks of chemotherapy can induce terminal myogenic differentiation in WT1-mutant tumors, but this is not associated with volume reduction. The time needed for all tumor cells to achieve the terminal differentiation state needs to be evaluated. In contrast, prolonged treatments can result in genetic alterations leading to resistance.

Image-based surgical risk factors for Wilms tumor

PURPOSE

The standard treatment for Wilms tumor (WT) is primary resection. However, in cases with unresectable tumor or tumor spillage, which are considered to have high surgical risks, more intensive chemotherapy and radiotherapy are required. In the present study, we retrospectively analyzed preoperative image parameters to identify factors associated with surgical risks.

METHODS

Twenty-nine patients with WT were enrolled in this study. Data on various preoperative image parameters, such as tumor size, tumor volume, displacement of great vessels, and contralateral extension of the tumor were collected, and their relationship with surgical factors, including operative time, hemorrhage, tumor spillage, and unresectability were analyzed.

RESULTS

Patients with unresectable tumor or with tumor spillage (surgical high-risk group) more frequently demonstrated displacement of great vessels and contralateral tumor extension. Operative time and blood loss were also significantly related to tumor size, area, volume, displacement of great vessels and contralateral extension.

CONCLUSION

Besides tumor size, displacement of great vessels and contralateral extension were significantly associated with surgical risks. These factors are easily determined using CT images and are, therefore, useful to decide whether preoperative chemotherapy should be started instead of primary tumor resection for large localized WTs.

Association between long interspersed nuclear element-1 methylation levels and relapse in Wilms tumors

Background

Wilms tumor (WT) is a curable pediatric renal malignancy, but there is a need for new molecular biomarkers to improve relapse risk-directed therapy. Somatic alterations occur at relatively low frequencies whereas epigenetic changes at 11p15 are the most common aberration. We analyzed long interspersed element-1 (LINE-1) methylation levels in the blastemal component of WT and normal kidney samples to explore their prognostic significance.

Results

WT samples presented a hypomethylated pattern at all five CpG sites compared to matched normal kidney samples; therefore, the averaged methylation levels of the five CpG sites were used for further analyses. WT presented a hypomethylation profile (median 65.0%, 47.4–73.2%) compared to normal kidney samples (median 71.8%, 51.5–77.5%; p < 0.0001). No significant associations were found between LINE-1 methylation levels and clinical–pathological characteristics. We observed that LINE-1 methylation levels were lower in tumor samples from patients with relapse (median methylation 60.5%) compared to patients without relapse (median methylation 66.5%; p = 0.0005), and a receiving operating characteristic curve analysis was applied to verify the ability of LINE-1 methylation levels to discriminate WT samples from these patients. Using a cut-off value of 62.71% for LINE-1 methylation levels, the area under the curve was 0.808, with a sensitivity of 76.5% and a specificity of 83.3%. Having identified differences in LINE-1 methylation between WT samples from patients with and without relapse in this cohort, we evaluated other prognostic factors using a logistic regression model. This analysis showed that in risk stratification, LINE-1 methylation level was an independent variable for relapse risk: the lower the methylation levels, the higher the risk of relapse. The logistic regression model indicated a relapse risk increase of 30% per decreased unit of methylation (odds ratio 1.30; 95% confidence interval 1.07–1.57).

Conclusion

Our results reinforce previous data showing a global hypomethylation profile in WT. LINE-1 methylation levels can be suggested as a marker of relapse after chemotherapy treatment in addition to risk classification, helping to guide new treatment approaches.

Electronic supplementary material

The online version of this article (10.1186/s13148-017-0431-6) contains supplementary material, which is available to authorized users.

Outcome and Prognostic Factors in Stage III Favorable-Histology Wilms Tumor: A Report From the Children's Oncology Group Study AREN0532

Background The National Wilms Tumor Study (NWTS) approach to treating stage III favorable-histology Wilms tumor (FHWT) is Regimen DD4A (vincristine, dactinomycin, and doxorubicin) and radiation therapy. Further risk stratification is required to improve outcomes and reduce late effects. We evaluated clinical and biologic variables for patients with stage III FHWT without combined loss of heterozygosity (LOH) at chromosomes 1p and 16q treated in the Children's Oncology Group protocol AREN0532. Methods From October 2006 to August 2013, 588 prospectively treated, centrally reviewed patients with stage III FHWT were treated with Regimen DD4A and radiation therapy. Tumor LOH at 1p and 16q was determined by microsatellite analysis. Ineligible patients (n = 5) and those with combined LOH 1p/16q (n = 40) were excluded. Results A total of 535 patients with stage III disease were studied. Median follow-up was 5.2 years (range, 0.2 to 9.5). Four-year event-free survival (EFS) and overall survival estimates were 88% (95% CI, 85% to 91%) and 97% (95% CI, 95% to 99%), respectively. A total of 58 of 66 relapses occurred in the first 2 years, predominantly pulmonary (n = 36). Eighteen patients died, 14 secondary to disease. A better EFS was associated with negative lymph node status ( P < .01) and absence of LOH 1p or 16q ( P < .01), but not with gross residual disease or peritoneal implants. In contrast, the 4-year EFS was only 74% in patients with combined positive lymph node status and LOH 1p or 16q. A total of 123 patients (23%) had delayed nephrectomy. Submitted delayed nephrectomy histology showed anaplasia (n = 8; excluded from survival analysis); low risk/completely necrotic (n = 7; zero relapses), intermediate risk (n = 63; six relapses), and high-risk/blastemal type (n=7; five relapses). Conclusion Most patients with stage III FHWT had good EFS/overall survival with DD4A and radiation therapy. Combined lymph node and LOH status was highly predictive of EFS and should be considered as a potential prognostic marker for future trials.

Tumor histopathological response to neoadjuvant chemotherapy in childhood solid malignancies: is it still impressive?

The management of oncological malignancies has significantly improved over the last decades. In modern medicine, new concepts and trends have emerged paving the way for the era of personalized and evidence-based strategies adapted to the patients’ prognostic variables and requirements. Several challenges do exist that are encountered during the management, including the difficulty to assess chemotherapy response with certainty. Having known that neoadjuvant chemotherapy might be the only solution for a proportion of patients with tumors that are unresectable at diagnosis, emergence of strategies that use risk group-directed therapy became an integral part in the management of oncological malignancies. Tumor histopathological change post neoadjuvant chemotherapy is one of the most important predictors of management outcome and is being used in many chemotherapy protocols as an essential determinant of the most suitable postoperative chemotherapy regimen. Bone tumors are the classic models of this approach; however, other childhood solid tumors show significant variations in outcome as a result of tumor histopathological response to neoadjuvant chemotherapy. The aim of this review is therefore to summarize the significance of histopathological responses seen after neoadjuvant chemotherapy in childhood solid tumors. Moreover, it suggests that the effect on tumor histopathology through modifying neoadjuvant chemotherapy and, on the other hand, toxicities from intensifying adjuvant chemotherapy might either necessitate the change of a number of arm groups in different protocol regimens or include newer chemotherapeutic agents adjuvantly for better outcome and lesser toxicities in poor tumor histopathological responders.

Glypican-3 mRNA expression level in Wilms tumor: correlation with histological type, stage, and outcome

PURPOSE

To correlate expression of Glypican-3 in Wilms tumor with histopathology, stage, and outcome.

METHODS

Glypican-3 mRNA expression by real-time PCR on tumor and normal germline samples from 75 fresh nephrectomies for Wilms tumor with fold change after normalization against GAPDH was compared. Survival analysis for event-free and overall survival (EFS, OS) with 2-year follow-up for Glypican-3 overexpression (>1.5 times) and clinicopathological parameters was performed.

RESULTS

Glypican-3 was overexpressed in 37/75 (49.3%). It was overexpressed in 77% (10/13) cases with blastema predominance or anaplastic histology, as compared to 44% of other histologies (27/62) (p = 0.03). OS was 73 and 93%, respectively (p = 0.016), for those with and without GPC-3 overexpression. EFS was not significantly different with Glypican-3 overexpression (p = 0.11). All 5 deaths among blastema predominant tumors and 4/5 deaths among triphasic tumors had overexpressed Glypican-3. Most deaths in Stage IV, Stage III, and Stage I + II (5/7, 3/3, 1/1) had GPC-3 overexpression. On multivariate analysis, only histology and stage were found to have independent prognostic value.

CONCLUSION

Glypican-3 overexpression in Wilms tumor correlates with poor OS on univariate analysis. However, only histology and stage have independent prognostic value. Glypican-3 levels may help to stratify intermediate outcome histology (triphasic) and Stage III Wilms tumors.

Synchronous occurrence of acute lymphoblastic leukemia and wilms tumor in two patients: underlying etiology and combined treatment plan

Synchronous cancers are extraordinarily rare in pediatric patients and present a therapeutic challenge. Patient A presented with synchronous unilateral Wilms tumor (WT) and standard-risk (SR) B-precursor acute lymphoblastic leukemia (ALL). Genetic testing revealed bialleleic BRCA2/FANCD1 mutations. Patient B, after SR B-precursor ALL induction therapy, was noted on fever workup to have a renal mass; pathology demonstrated lesion indeterminate between WT and nephrogenic rest. Therapy was customized for each patient to treat both cancers. Both patients have ongoing remission from their cancers, without excessive toxicity. We report two regimens for treating synchronous WT and ALL and recommend screening such patients for cancer predisposition.

Apparent diffusion coefficient as it relates to histopathology findings in post-chemotherapy nephroblastoma: a feasibility study

BACKGROUND

Nephroblastomas represent a group of heterogeneous tumours with variable proportions of distinct histopathological components.

OBJECTIVE

The purpose of this study was to investigate whether direct comparison of apparent diffusion coefficient (ADC) measurements with post-resection histopathology subtypes is feasible and whether ADC metrics are related to histopathological components.

MATERIALS AND METHODS

Twenty-three children were eligible for inclusion in this retrospective study. All children had MRI including diffusion-weighted imaging (DWI) after preoperative chemotherapy, just before tumour resection. A pathologist and radiologist identified corresponding slices at MRI and postoperative specimens using tumour morphology, the upper/lower calyx and hilar vessels as reference points. An experienced reader performed ADC measurements, excluding non-enhancing areas. A pathologist reviewed the corresponding postoperative slides according to the international standard guidelines. We tested potential associations with the Spearman rank test.

RESULTS

Side-by-side comparison of MRI-DWI with corresponding histopathology slides was feasible in 15 transverse slices in 9 lesions in 8 patients. Most exclusions were related to extensive areas of necrosis/haemorrhage. In one lesion correlation was not possible because of the different orientation of sectioning of the specimen and MRI slices. The 25% ADC showed a strong relationship with percentage of blastema (Spearman rho=-0.71, P=0.003), whereas median ADC was strongly related to the percentage stroma (Spearman rho=0.74, P=0.002) at histopathology.

CONCLUSION

Side-by-side comparison of MRI-DWI and histopathology is feasible in the majority of patients who do not have massive necrosis and hemorrhage. Blastemal and stromal components have a strong linear relationship with ADC markers.

Risk stratification for wilms tumor: current approach and future directions

Wilms tumor, or nephroblastoma, has provided a paradigm for progressive improvement in clinical outcomes achieved through serial cooperative group studies. With modern surgery, chemotherapy, and radiation therapy approaches, the overall survival rate for patients with Wilms tumor has reached 90%. Remarkably, the increase in survival has been achieved with a reduction in therapy for most patient subgroups, leading not only to more survivors, but also to healthier survivors. A key contributor to improved outcomes has been the development of clinical and biologic prognostic markers that have enabled risk-directed therapy. Whereas the early cooperative group studies used only tumor stage for risk stratification, current Children's Oncology Group (COG) and International Society of Pediatric Oncology (SIOP) protocols employ a multitude of prognostic factors to guide therapy. Prognostic factors used in the current generation of COG studies include stage, histology, patient age, tumor weight, completeness of lung nodule response, and loss of heterozygosity at chromosomes 1p and 16q. Future COG studies seek to incorporate gain of chromosome 1q and methylation pattern of chromosome 11p15 into the risk classification schema. Prognostic factors used in the current SIOP studies include stage, histology, tumor volume, and responsiveness to therapy. Future SIOP studies seek to incorporate absolute blastemal volume and novel molecular markers for resistant blastema into the risk stratification approach.

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

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

Omission of doxorubicin from the treatment of stage II-III, intermediate-risk Wilms' tumour (SIOP WT 2001): an open-label, non-inferiority, randomised controlled trial

BACKGROUND

Before this study started, the standard postoperative chemotherapy regimen for stage II-III Wilms' tumour pretreated with chemotherapy was to include doxorubicin. However, avoidance of doxorubicin-related cardiotoxicity effects is important to improve long-term outcomes for childhood cancers that have excellent prognosis. We aimed to assess whether doxorubicin can be omitted safely from chemotherapy for stage II-III, histological intermediate-risk Wilms' tumour when a newly defined high-risk blastemal subtype was excluded from randomisation.

METHODS

For this international, multicentre, open-label, non-inferiority, phase 3, randomised SIOP WT 2001 trial, we recruited children aged 6 months to 18 years at the time of diagnosis of a primary renal tumour from 251 hospitals in 26 countries who had received 4 weeks of preoperative chemotherapy with vincristine and actinomycin D. Children with stage II-III intermediate-risk Wilms' tumours assessed after delayed nephrectomy were randomly assigned (1:1) by a minimisation technique to receive vincristine 1·5 mg/m(2) at weeks 1-8, 11, 12, 14, 15, 17, 18, 20, 21, 23, 24, 26, and 27, plus actinomycin D 45 μg/kg every 3 weeks from week 2, either with five doses of doxorubicin 50 mg/m(2) given every 6 weeks from week 2 (standard treatment) or without doxorubicin (experimental treatment). The primary endpoint was non-inferiority of event-free survival at 2 years, analysed by intention to treat and a margin of 10%. Assessment of safety and adverse events included systematic monitoring of hepatic toxicity and cardiotoxicity. This trial is registered with EudraCT, number 2007-004591-39, and is closed to new participants.

FINDINGS

Between Nov 1, 2001, and Dec 16, 2009, we recruited 583 patients, 341 with stage II and 242 with stage III tumours, and randomly assigned 291 children to treatment including doxorubicin, and 292 children to treatment excluding doxorubicin. Median follow-up was 60·8 months (IQR 40·8-79·8). 2 year event-free survival was 92·6% (95% CI 89·6-95·7) for treatment including doxorubicin and 88·2% (84·5-92·1) for treatment excluding doxorubicin, a difference of 4·4% (95% CI 0·4-9·3) that did not exceed the predefined 10% margin. 5 year overall survival was 96·5% (94·3-98·8) for treatment including doxorubicin and 95·8% (93·3-98·4) for treatment excluding doxorubicin. Four children died from a treatment-related toxic effect; one (<1%) of 291 receiving treatment including doxorubicin died of sepsis, three (1%) of 292 receiving treatment excluding doxorubicin died of varicella, metabolic seizure, and sepsis during treatment for relapse. 17 patients (3%) had hepatic veno-occlusive disease. Cardiotoxic effects were reported in 15 (5%) of 291 children receiving treatment including doxorubicin. 12 children receiving treatment including doxorubicin, and ten children receiving treatment excluding doxorubicin, died, with the remaining deaths from tumour recurrence.

INTERPRETATION

Doxorubicin does not need to be included in treatment of stage II-III intermediate risk Wilms' tumour when the histological response to preoperative chemotherapy is incorporated into the risk stratification.

FUNDING

See Acknowledgments for funders.

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.

A multi-Gaussian model for apparent diffusion coefficient histogram analysis of Wilms' tumour subtype and response to chemotherapy

Wilms' tumours (WTs) are large heterogeneous tumours, which typically consist of a mixture of histological cell types, together with regions of chemotherapy-induced regressive change and necrosis. The predominant cell type in a WT is assessed histologically following nephrectomy, and used to assess the tumour subtype and potential risk. The purpose of this study was to develop a mathematical model to identify subregions within WTs with distinct cellular environments in vivo, determined using apparent diffusion coefficient (ADC) values from diffusion-weighted imaging (DWI). We recorded the WT subtype from the histopathology of 32 tumours resected in patients who received DWI prior to surgery after pre-operative chemotherapy had been administered. In 23 of these tumours, DWI data were also available prior to chemotherapy. Histograms of ADC values were analysed using a multi-Gaussian model fitting procedure, which identified 'subpopulations' with distinct cellular environments within the tumour volume. The mean and lower quartile ADC values of the predominant viable tissue subpopulation (ADC(1MEAN), ADC(1LQ)), together with the same parameters from the entire tumour volume (ADC(0MEAN), ADC(0LQ)), were tested as predictors of WT subtype. ADC(1LQ) from the multi-Gaussian model was the most effective parameter for the stratification of WT subtype, with significantly lower values observed in high-risk blastemal-type WTs compared with intermediate-risk stromal, regressive and mixed-type WTs (p < 0.05). No significant difference in ADC(1LQ) was found between blastemal-type and intermediate-risk epithelial-type WTs. The predominant viable tissue subpopulation in every stromal-type WT underwent a positive shift in ADC(1MEAN) after chemotherapy. Our results suggest that our multi-Gaussian model is a useful tool for differentiating distinct cellular regions within WTs, which helps to identify the predominant histological cell type in the tumour in vivo. This shows potential for improving the risk-based stratification of patients at an early stage, and for guiding biopsies to target the most malignant part of the tumour.

Efficacy of Preoperative Chemotherapy in Treatment of Children With Wilms' Tumor: A Meta-Analysis

Context:

To assess the efficacy of preoperative chemotherapy in Wilms’ tumor patients and explore its true value for specific subgroups.

Objectives:

In the presence of these controversies, a meta-analysis that examines the efficacy of preoperative chemotherapy in Wilms’ tumor patients and specific subgroups is needed to clarify these issues. The objective of this meta-analysis is to assess the efficacy of preoperative chemotherapy in Wilms’ tumor patients and explore its true value for specific subgroups.

Data Sources:

Computer-based systematic search with “preoperative chemotherapy”, “Neoadjuvant Therapy” and “Wilms’ tumor” as search terms till January 2013 was performed.

Study Selection:

No language restrictions were applied. Searches were limited to randomized clinical trials (RCTs) or retrospective studies in human participants under 18 years. A manual examination of references in selected articles was also performed.

Data Extraction:

Relative Risk (RR) and their 95% Confidence Interval (CI) for Tumor Shrinkage (TS), total Tumor Resection (TR), Event-Free Survival (EFS) and details of subgroup analysis were extracted. Meta-analysis was carried out with the help of the software STATA 11.0. Finally, four original Randomized Clinical Trials (RCTs) and 28 retrospective studies with 2375 patients were included.

Results:

For preoperative chemotherapy vs. up-front surgery (PC vs. SU) group, the pooled RR was 9.109 for TS (95% CI: 5.109 - 16.241; P < 0.001), 1.291 for TR (95% CI: 1.124 - 1.483; P < 0.001) and 1.101 for EFS (95% CI: 0.980 - 1.238; P = 0.106). For subgroup short course vs. long course (SC vs. LC), the pooled RR was 1.097 for TS (95% CI: 0.784 - 1.563; P = 0.587), 1.197 for TR (95% CI: 0.960 - 1.493; P = 0.110) and 1.006 for EFS (95% CI: 0.910 - 1.250; P = 0.430).

Conclusions:

Short course preoperative chemotherapy is as effective as long course and preoperative chemotherapy only benefits Wilms’ tumor patients in tumor shrinkage and resection but not event-free survival.

Use of 18F-FDG-PET-CT for Assessment of Response to Neoadjuvant Chemotherapy in Children With Wilms Tumor

PURPOSE

The aim of this study was to evaluate the predictive value of fluorine-18-fluorodeoxyglucose positron emission tomography with computed tomography (F-FDG-PET-CT) in the assessment of histologic response to neoadjuvant chemotherapy in children with Wilms tumors (WTs).

MATERIALS AND METHODS

We prospectively registered 12 patients with WTs who were treated with 2 cycles of neoadjuvant chemotherapy and surgery. All patients underwent sequential F-FDG-PET-CT before (PET-CT1) and after (PET-CT2) neoadjuvant chemotherapy. Maximum standardized uptake value (SUVmax) was measured on PET-CT1 (SUV1) and PET-CT2 (SUV2). The percentage change in SUVmax (SUVmax reduction) was calculated. After surgery the effects of neoadjuvant chemotherapy were graded histopathologically: ≥90% necrosis indicated a good response and <90% necrosis was considered a poor response. The correlation between SUVmax reduction and histologic response was estimated using the Spearman correlation coefficient.

RESULTS

Among the 12 patients who underwent PET-CT before and after chemotherapy, SUVmax reduction was significantly different between the good response group and the poor response group (P=0.035). A significant, in terms of P value, correlation was found between pathologic response and SUVmax reduction (r=0.700; 95% confidence interval, 0.060-0.935; P=0.011). A threshold of 66% reduction in SUVmax was identified, with which partition, there were 8 good histologic responders (≥66% decrease in SUVmax) and 4 poor responders. The histologic complete response rate of the good responders was 87.5%, whereas that of poor responders was 0%. SUV1≥7 and SUV2≥2.4 were both considered to be with high risk of recurrence. In patients with SUV1≥7, 4/5 cases relapsed and 4/6 patients with SUV2≥2.4 relapsed.

CONCLUSIONS

As there seems to be a good correlation of changes in SUVmax and histologic response, PET-CT has the potential of predicting the response to neoadjuvant chemotherapy in children with WT. SUV1 and SUV2 by themselves might be a good prognosticator of the clinical outcome of WT pediatric patients treated with International Society of Pediatric Oncology protocols, although the reduction rate of SUVmax is much less powerful for prognosis.

Wilms' tumour: Determinants of prognosis in an African setting

BACKGROUND

The few studies available in the literature on Wilms' tumour (WT) from sub-Saharan Africa have reported a dismal outcome for children with the tumour. This study evaluated the risk factors that have been correlated with outcome in the literature and compare these with outcome among our patients.

MATERIALS AND METHODS

Cases of histologically confirmed WT between 2009 and 2013 in a tertiary hospital in Northwestern Nigeria were evaluated for gender, age, laterality, symptoms, duration before presentation, stage at presentation, histologic subtype and p53 mutation. These were then correlated with outcome.

RESULTS

Totally, 30 cases of WT were diagnosed with mean age of 4.8 ± 1.9 years; and male:female ratio of 2:1. No statistically significant relationship with outcome was found for gender (P = 0.138) or histologic subtype (P = 0.671). The most significant variables which positively influenced the outcome were presentation at earlier stages (P = 0.007) and completion of therapy (P = 0.0007). p53 mutation was seen in 3 (16.7%) of 18 cases and was not associated with a poor outcome (P = 0.089). However, 2 of the 3 cases presented in Stage IV and none of them survived the 1 st year.

CONCLUSION

This study shows that even though p53 mutation was associated with a more aggressive phenotype, the most significant determinants of a good outcome among patients in a developing country like ours is non-blastemal dominant histologic subtype, early stage at presentation and completion of therapy.

Outcome of localised blastemal-type Wilms tumour patients treated according to intensified treatment in the SIOP WT 2001 protocol, a report of the SIOP Renal Tumour Study Group (SIOP-RTSG)

Blastemal-type Wilms tumour (BT-WT) has been identified as a high risk histological subgroup in WT assessed after pre-nephrectomy chemotherapy in trials of the International Society of Paediatric Oncology (SIOP) Renal Tumour Study Group. Therefore, in SIOPWT2001, post-operative chemotherapy for BT-WT was intensified aiming to improve survival. Survival analysis of all unilateral BT-WT patients (SIOPWT2001) (n=238), was compared with historical BT-WT controls (SIOP93-01) (n=113). 351/4061 (8.6%) unilateral non-metastatic BT-WT patients (SIOP93-01/SIOPWT2001) were studied. Median age at diagnosis was 43 months (Inter Quartile Range (IQR) 24-68 months), stages: I (n=140, 40%), II (n=106, 30%), III (n=105, 30%). BT-WTs were higher staged, showed greater volume decrease after pre-operative chemotherapy and were diagnosed at an older median age compared to other WT patients. Patient characteristics did not differ substantially between SIOP93-01 and SIOPWT2001. Univariate analysis showed a 5-year event-free survival (EFS) of 80% (95% confidence interval (CI): 75-86%) (SIOPWT2001) compared to 67% in SIOP93-01 (95% CI: 59-76%; p=0.006) and overall survival (OS) of 88% (95% CI: 83-93%) (SIOPWT2001) compared to 84% (95% CI: 77-91%; p=0.4) in SIOP93-01. 95% of relapses were distant metastases (SIOP93-01/SIOPWT2001). Treatment protocol, age at diagnosis, tumour stage (III versus I/II) and volume (at surgery), were prognostic variables for EFS (uni- and multivariate Cox regression analysis). Independent prognosticators for OS were age at diagnosis, tumour stage and volume (at surgery). The most significant survival benefit of intensified treatment, was observed in Stage I (EFS 96% in SIOPWT2001 (OS 100%), 71% in SIOP93-01 (OS 90%)). BT-WT derived benefits from more intensive chemotherapy as reflected by a reduction in relapse risk. However, the benefit of the more intensive chemotherapy to improve OS was only observed in stage I BT-WTs, by adding doxorubicin.

Mutations in the SIX1/2 pathway and the DROSHA/DGCR8 miRNA microprocessor complex underlie high-risk blastemal type Wilms tumors

Blastemal histology in chemotherapy-treated pediatric Wilms tumors (nephroblastoma) is associated with adverse prognosis. To uncover the underlying tumor biology and find therapeutic leads for this subgroup, we analyzed 58 blastemal type Wilms tumors by exome and transcriptome sequencing and validated our findings in a large replication cohort. Recurrent mutations included a hotspot mutation (Q177R) in the homeo-domain of SIX1 and SIX2 in tumors with high proliferative potential (18.1% of blastemal cases); mutations in the DROSHA/DGCR8 microprocessor genes (18.2% of blastemal cases); mutations in DICER1 and DIS3L2; and alterations in IGF2, MYCN, and TP53, the latter being strongly associated with dismal outcome. DROSHA and DGCR8 mutations strongly altered miRNA expression patterns in tumors, which was functionally validated in cell lines expressing mutant DROSHA.

[Tumor size and prognosis in patients with Wilms tumor]

OBJECTIVE

Investigate the relationship of the tumor volume after preoperative chemotherapy (TVAPQ) and before preoperative chemotherapy (TVBPQ) with overall survival at two and at five years, and lifetime.

METHODS

Our sample consisted of consecutive patients evaluated in the period from 1989 to 2009 in an Onco-Hematology Service. Clinical, histological and volumetric data were collected from the medical records. For analysis, chi-square, Kaplan-Meier, log-rank and Cox regression tests were used.

RESULTS

The sample consisted of 32 patients, 53.1% were male with a median age at diagnosis of 43 months. There was a significant association between TVAPQ >500 mL and the difference between the TVBPQ and TVAPQ (p=0.015) and histologic types of risk (p=0.008). It was also verified an association between the difference between the TVBPQ and TVAPQ and the predominant stromal tumor (p=0.037). When assessing the TVAPQ of all patients, without a cutoff, there was an association of the variable with lifetime (p=0.013), i.e., for each increase of 10 mL in TVAPQ there was an average increase of 2% in the risk of death.

CONCLUSIONS

Although our results indicate that the TVAPQ could be considered alone as a predictor of poor prognosis regardless of the cutoff suggested in the literature, more studies are needed to replace the histology and staging by tumor size as best prognostic variable.

Pathological Features of the Unilateral Favorable Histology Nephroblastoma with Relapse

PURPOSE

To evaluate the pathological features of the primary lesion in patients with relapse of unilateral favorable histology nephroblastoma.

MATERIAL AND METHODS

Fifty-eight patients with unilateral favorable histology nephroblastoma who underwent initial nephrectomy before chemotherapy were categorized into one of two groups: the nonrelapsed group (n = 52) and the relapsed group (n = 6). The histological subtypes of both groups and pathological features of the relapsed group were re-evaluated retrospectively.

RESULTS

The histological subtypes of all relapsed cases were classified as blastemal predominant. In three of six cases with relapse, sheets of spindle-shaped blastemal cells that were histologically reminiscent of synovial sarcoma were predominant (massive sarcomatoid pattern).

CONCLUSIONS

The histological blastemal predominant subtype of nephroblastoma is a strong indicator of relapse. In particular, the blastemal predominant subtype with massive sarcomatoid pattern may have a higher risk of relapse.

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.

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.

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.