Outcome of pediatric renal tumor treated using the Japan Wilms Tumor Study-1 (JWiTS-1) protocol: a report from the JWiTS group

A higher tumor volume and undernutrition at diagnosis adversely affect the survival of children with Wilms tumor: A study of 200 patients

BACKGROUND

Distinct prognostic factors for Wilms tumor (WT) in low- and middle-income countries need identification.

METHODS

Retrospective study of patients with WT managed by the International Society of Pediatric Oncology (SIOP) approach for over 11 years (2005-2016) at a single center in Chandigarh, India.

RESULTS

The study included 200 patients (median age: 33.5 months). The tumor stage (SIOP) distribution included stage I (30%), II (36%), III (14%), IV (17%), and V (3%). The histology-risk groups were low (8%), intermediate (84%), and high risk (9%). At diagnosis, 68 out of 190 (36%) patients were underweight. The median tumor volume at diagnosis was 481 ml (interquartile ratio [IQR]: 306.9, 686.8, n = 146). Following neoadjuvant chemotherapy, it reduced to 110 ml (IQR: 151.2, 222, n = 77). Treatment was abandoned in 20.5% of the patients. Treatment-related mortality occurred in 13 of 179 (7.2%) patients. Relapse occurred in 26 of 158 (16.5%) patients. The 3-year overall survival (OS) and event-free survival (EFS) of patients who completed therapy were 78.3 and 72%, respectively. The stage (p = .013) and histology (p = .023) influenced OS. A lower OS in stage II (75.4%) versus stage III disease (83.7%) suggested understaging. Patients with a higher tumor volume at diagnosis (p = .005; odds ratio [OR]: 0.99; 95% confidence interval [CI]: 0.99-1.00) or a lower weight-for-age z-score (p = .002; OR: 1.68; 95% CI: 1.21-2.33) had an increased risk of death or relapse.

CONCLUSIONS

The 3-year OS and EFS of children who completed therapy were 78.3 and 72%, respectively. A higher tumor volume and lower weight-for-age z-score at diagnosis were identified as distinct adverse prognostic factors. A likely suboptimal lymph node assessment (intraoperative and histopathology) contributed to the understaging of stage III to II disease and reduced survival.

Overall survival nomogram and relapse-related factors of clear cell sarcoma of the kidney: A study based on published patients

Background

Rarity limits the breadth of study on clear cell sarcoma of the kidney (CCSK). There is currently no predictive model that quantifies the overall survival (OS) of CCSK and a few large sample-based analysis of relapse-related factors.

Methods

Patients were collected both from the Surveillance, Epidemiology, and End Results (SEER) database and case report articles extracted from the global online document database to form 2 groups. The first was the OS group, which was used to build and verify the nomogram for predicting the OS of CCSK. Independent predictors of OS were screened by Cox regression analysis to develop the nomogram. Nomogram accuracy was assessed by C-index, receiver operating characteristic (ROC), calibration, and decision curve analysis (DCA) curves. In addition, the difference in OS between receiving radiotherapy or not in stage I patients was analyzed by the Chi-square test. The second was the relapse group, which was used to analyze the relapse-related factors by Cox regression analysis and the Kaplan-Meier method with the log-rank test.

Result

256 patients were included in the OS group. The stage, chemotherapy, and radiotherapy were independent OS-related factors of CCSK, and the nomogram for predicting the OS of CCSK was established based on them. The results of the C-index, ROC, calibration, and DCA curves showed that the nomogram has good discrimination, accuracy, and clinical profitability. The Chi-squared test showed no significant difference in OS with receiving radiotherapy or not in stage I patients. The relapse group included 153 patients, of which 60 relapsed. The univariate Cox regression analysis showed no correlation between radiotherapy and relapse. The multivariate Cox regression analysis showed that stage and surgery/chemotherapy sequence were the independent factors for relapse. The log-rank test of seven chemotherapeutic drugs showed that etoposide (E), cyclophosphamide (C), vincristine (V), and doxorubicin (D) (all P < 0.05) had significant differences in preventing relapse, and then drew the relapse-free survival curves of these four drugs.

Conclusion

Our nomogram accurately quantified the OS of CCSK. There was no significant difference in OS between receiving radiotherapy or not in stage I patients. Stage, surgery/chemotherapy sequence, and the use of ECVD were relapse-related factors. Radiotherapy had no significant contribution to preventing relapse.

A 10-year study of the outcome of wilms' tumor in central India and identifying practice gaps

Introduction:

Despite remarkable improvement in Wilms' tumor (WT) survival in Western world, sub-optimal outcome in resource-constrained settings is influenced by late presentation, larger size, and poor access to treatment. This prompted us to study the outcome at a tertiary care center and to identify the global and local practice gaps.

Materials and Methods:

A retrospective, observational study of WT was conducted from October 2009 to September 2019 at a tertiary care setting. Following the National Wilms' Tumor Study Group protocol, an upfront nephrectomy (unilateral resectable tumors) and preoperative chemotherapy (large/unresectable Stage I–III) were followed. The records were reviewed for demographics, stage, preoperative chemotherapy, predictive factors, and outcome. Survival curves were plotted by the Kaplan–Meier method, and analysis was performed using the SPSS software version 16.

Results:

One hundred and fifty-six children were included, median age was 4.1 years, with a male predominance. The most common stages of the presentation were II (40.4%) and III (34.6%). An upfront surgery was done in 27.6%, while remaining received preoperative chemotherapy. The median follow-up was 22 months, and the events included relapse in 46 (29.48%) and death in 54 (34.61%). The mean survival time was 45.7 (95% confidence interval [CI], 41.08–50.30). The 2-year overall survival was 65.38% (95% CI, 59–73), and the 2-year event-free survival was 36% (95% CI, 32–41). On comparison of the impact of preoperative chemotherapy, the survival estimates in Stages I–III and relapse rate were statistically similar, tumor size reduced significantly, and tumor spill was significantly lower (P < 0.05).

Conclusion:

WT is associated with late presentation, sub-optimal survival, and higher relapse in our setting associated with practice gaps related to the management including practice violations.

Comparative analysis of the clinical characteristics and outcomes of patients with Wilms tumor in the United Kingdom and Japan

BACKGROUND

Wilms tumor (WT) demonstrates epidemiological differences by world region and ethnicity. To enhance understanding of these differences, we retrospectively analyzed clinical trial data sets from the UK and Japan over a 20-year period.

PROCEDURE

We used data from three consecutive clinical trials in the UK and a single study in Japan that enrolled patients diagnosed during 1996-2015, to compare clinical characteristics and outcomes between countries.

RESULTS

During 1996-2015, 1395 patients in the UK and 537 in Japan were included. Japanese patients have a significantly younger median age at diagnosis than those in the UK (28 months vs 39 months). The proportion of patients with stage IV, large tumors, and anaplastic histology appears to be higher in the UK than in Japan (18% vs 11%, 62% vs 49%, 8% vs 3%, respectively). During 2005-2015, 77 hospitals treated WT in Japan compared with only 20 hospitals in the UK. Five-year overall survival of patients with WT was over 90% in both countries, but five-year event-free survival of patients with stage IV was significantly lower in Japan than in the UK (50.0% vs 76.2%, P = 0.001).

CONCLUSIONS

Differences in age of onset, tumor size at diagnosis, and histology may reflect differences in the genetic background of patients with WT between countries, but population-based phenotype-genotype data are lacking. The difference in survival probability for stage IV patients may be due to different diagnostic criteria or different treatment strategies. Prospective, international clinical studies including genomic analyses are needed to confirm these findings and improve clinical practice.

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.

Frequent breakpoints of focal deletion and uniparental disomy in 22q11.1 or 11.2 segmental duplication region reveal distinct tumorigenesis in rhabdoid tumor of the kidney

SMARCB1 is mutated in most rhabdoid tumors (RTs) developing in the kidney (RTK) and various other organs. Focal deletions found in patients with 22q11.2 deletion syndrome show breakpoints within clusters of segmental duplications (SDs), and those in some RTs show breakpoints in the 22q11-q12 region. SDs are known to cause focal deletion mediated by non-allelic homologous recombination. The present study identified SMARCB1 alterations in all 30 RTKs, using SNP array CGH, MLPA, and sequence analyses. Twenty-eight tumors had a total of 51 breakpoints forming focal 22q deletion and/or uniparental disomy (22qUPD), and the other two had compound mutation with no breakpoints in 22q. Twenty-four (47.1%) of the 51 breakpoints were within SDs, and occurred in 16 (53.3%) of the 30 tumors. The association of breakpoints with SDs was found not only in focal deletion, but also in 22qUPD, indicating that SDs mediate the first and second hits (focal deletion) and the second hit (22qUPD) of SMARCB1 alteration. Of the 51 breakpoints, 14 were recurrent, and 10 of the 14 were within SDs, suggesting the presence of hotspots in the 22q11.2 region. One recurrent breakpoint outside SDs resided in SMARCB1, suggesting inactivation of the gene by out-of-frame fusion. The association between SDs and focal deletion has been reported in two other types of cancer. RTKs may be the third example of SD-associated tumors. Thus, the present study indicated that RTKs exploit genomic instability in the 22q11.1-11.2 SDs region, and 22qUPD caused by mitotic recombination may also be mediated by SDs.

Childhood Clear Cell Sarcoma of Kidney: Incidence and Survival

This study is to describe current incidence of childhood clear cell sarcoma of kidney (CCSK) and to investigate the present survival of this cancer. Surveillance, Epidemiology, and End Result (SEER) data was used to identify children with CCSK and Wilms tumor (WT) aged 0-19 years in the US. Age-adjusted incidences were estimated over the decades. Age- and sex-specific epidemiology was also presented. Propensity score matching was used to balance features of CCSK and WT cases. Log rank test was used to compare survivals and Cox regression was used to evaluate independent effects of factors. The present age-adjusted incidence of childhood CCSK was 0.205 per million, which remained stable for years and ranked third in all pediatric renal tumors. The incidence rate ratios for boy and age under 4 were 3 and 21, respectively. The current 5-year overall survival (OS) rate for CCSK was 87%, which is not evidently inferior to that for WT (90%); however the outcome of CCSK was significantly poorer if both groups were well-balanced (OS rate was 86 vs. 95%). Early year of diagnosis and distant metastasis were independent survival factors. In conclusion, occurrence of CCSK remains stable over the years, with an age-adjusted incidence of 0.205 per million. Boy and age under 4 are risk factors for tumor development. CCSK currently has a favorable outcome but its nature may be more aggressive than common kidney tumor, which in turn proves efficacy of modern treatment.

Renal tumours in Australian children: 30 years of incidence, outcome and second primary malignancy data from the Australian Childhood Cancer Registry

AIM

This paper describes the incidence and outcomes of childhood renal malignancies in Australia using national population-based data from the Australian Childhood Cancer Registry.

METHODS

De-identified data for children (0-14 years) diagnosed with renal malignancies from 1983 to 2015 inclusive were extracted. Cause-specific (CSS) and event-free survival up to 20 years from diagnosis were estimated using the cohort method. Adjusted excess mortality hazard ratios were calculated using a multivariable flexible parametric survival model. Details relating to second primary malignancies (SPMs) were also examined.

RESULTS

There were 1046 children diagnosed with renal malignancies in Australia between 1983 and 2015 (91% nephroblastoma), generating an annual age-standardised incidence rate of 8 per million children, which remained constant over the study period. CSS was 89% (95% confidence interval = 87-91%) and 88% (86-90%) at 5 and 20 years, respectively, and 5-year event-free survival was 82% (80-84%). Five-year CSS did not change over the study period and was highest for nephroblastoma (91%). Of the 94% of patients achieving remission, 15% relapsed and subsequent 5-year CSS was 49% (40%-58%). Eleven children were diagnosed with SPM (standardised incidence ratio = 2.9, 95% confidence interval = 1.6-5.3, P < 0.001), and five of them (45%) died within 5 years of the second diagnosis.

CONCLUSIONS

Children treated for renal malignancies in Australia have excellent long-term survival, which is unchanged since 1983. SPMs are uncommon following treatment for childhood renal cancer but carry a poor prognosis. Relapse carries a similarly poor prognosis to SPM but is more common. These data are comparable to registry outcomes in similarly developed nations.

Factors responsible for stage III disease in patients with Wilms tumor enrolled in the JWiTS-2 study

BACKGROUND/OBJECTIVES

Treatment is more intensive for stage III Wilms tumor (WT) than for stages I and II non-metastatic WTs. Various factors including tumor spillage, unresectability, and lymph node metastasis are responsible for stage III disease. The present study aimed to not identify clinical factors associated with the features of stage III WT to establish new treatment strategies.

DESIGN/METHODS

Of 166 patients with non-metastatic WT enrolled in the Japan Wilms Tumor Study (JWiTS)-2, 51 patients had stage III disease. The treatment protocol for JWiTS-2 was essentially the same as that in the National Wilms Tumor study (NWTS)-5. Local hospitals were surveyed to collect details of clinical findings related to stage III disease, and data regarding 45 (88%) patients were obtained.

RESULTS

Nine patients with massive tumors underwent preoperative chemotherapy. Biopsy was performed in 6. Reduction in the tumor size was achieved in 8 of the 9 cases. Nephrectomy was finally performed in all of them. Thirty-six patients underwent primary nephrectomy. The reason for the stage III disease was lymph node metastasis (n = 9, 25%), tumor spillage (n = 20, 56%), and tumor extension/incomplete resection (n = 17, 47%). Some patients had more than one of these factors. Most patients were treated with the DD-4A regimen, and 43 (95.6%) of the 45 patients received abdominal radiation therapy. Tumors recurred in three patients (local, 1; metastasis, 2), and two patients died. Overall and relapse-free survival rates were 95.2% and 90.8%, respectively.

CONCLUSION

The prognosis of stage III WT was good. In the next stage, the doses of chemotherapy and radiotherapy should be reduced to avoid late effects. The high rate of tumor spillage after primary resection suggests that preoperative chemotherapy should be started instead of aggressive tumor resection in the large tumor cases with surgical risks.

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.

p53 Is a Master Regulator of Proteostasis in SMARCB1-Deficient Malignant Rhabdoid Tumors

Alterations in chromatin remodeling genes have been increasingly implicated in human oncogenesis. Specifically, the biallelic inactivation of the SWI/SNF subunit SMARCB1 results in the emergence of extremely aggressive pediatric malignancies. Here, we developed embryonic mosaic mouse models of malignant rhabdoid tumors (MRTs) that faithfully recapitulate the clinical-pathological features of the human disease. We demonstrated that SMARCB1-deficient malignancies exhibit dramatic activation of the unfolded protein response (UPR) and ER stress response via a genetically intact MYC-p19^ARF-p53 axis. As a consequence, these tumors display an exquisite sensitivity to agents inducing proteotoxic stress and inhibition of the autophagic machinery. In conclusion, our findings provide a rationale for drug repositioning trials investigating combinations of agents targeting the UPR and autophagy in SMARCB1-deficient MRTs.

Combined Genetic and Chromosomal Characterization of Wilms Tumors Identifies Chromosome 12 Gain as a Potential New Marker Predicting a Favorable Outcome

To identify prognostic factors, array CGH (aCGH) patterns and mutations in WT1 and 9 other genes were analyzed in 128 unilateral Wilms tumors (WTs). Twenty patients had no aCGH aberrations, and 31 had WT1 alterations [silent and WT1 types: relapse-free survival (RFS), 95% and 83%, respectively]. Seventy-seven patients had aCGH changes without WT1 alterations (nonsilent/non-WT1 type) and were subtyped into those with or without +12, 11q-, 16q-, or HACE1 loss. RFS was better for those with than those without +12 (P = .010) and worse for those with than those without 11q-, 16q-, or HACE1 loss (P = .001, .025, or 1.2E-04, respectively). Silent and WT1 type and 8 subtype tumors were integrated and classified into 3 risk groups: low risk for the silent type and +12 subgroup; high risk for the no +12 plus 11q-, 16q-, or HACE1 loss subgroup; intermediate risk for the WT1 type and no +12 plus no 11q-, 16q-, or HACE1 loss subgroup. Among the 27 WTs examined, the expression of 146 genes on chromosome 12 was stronger in +12 tumors than in no +12 tumors, while that of 10 genes on 16q was weaker in 16q- tumors than in no 16q- tumors. Overexpression in 75 out of 146 upregulated genes and underexpression in 7 out of 10 downregulated genes correlated with better and worse overall survival, respectively, based on the public database. +12 was identified as a potential new marker predicting a favorable outcome, and chromosome abnormalities may be related to altered gene expression associated with these abnormalities.

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

BACKGROUND

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

PROCEDURE

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

RESULTS

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

CONCLUSIONS

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

Position paper: Rationale for the treatment of children with CCSK in the UMBRELLA SIOP-RTSG 2016 protocol

The International Society of Paediatric Oncology-Renal Tumour Study Group (SIOP-RTSG) has developed a new protocol for the diagnosis, treatment, and follow-up monitoring of childhood renal tumours - the UMBRELLA SIOP-RTSG 2016 protocol (the UMBRELLA protocol). This protocol has been designed to continue international collaboration in the treatment of childhood renal tumours and will be implemented in over 50 different countries. Clear cell sarcoma of the kidney, which is a rare paediatric renal tumour that most commonly occurs in children between 2 and 4 years of age, is specifically addressed in the UMBRELLA protocol.

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.

Predictive factor for intraoperative tumor rupture of Wilms tumor

PURPOSE

For Wilms tumor, intraoperative tumor rupture with wide tumor spillage during surgical manipulation raises the classification to stage 3. Then, postoperative chemotherapy must be more intensive, and abdominal radiotherapy is added. Therefore, intraoperative tumor rupture should be avoided if possible. However, predictive factors for intraoperative tumor rupture have not been sufficiently described. Here we examined the risk factors for intraoperative tumor rupture.

METHODS

Patients with Wilms tumor who underwent treatment according to the National Wilms Tumor Study or the Japanese Wilms Tumor Study protocol at our institution were reviewed retrospectively. Collected cases were categorized into two groups: the ruptured group and the non-ruptured group. Risk factors for intraoperative tumor rupture, including the ratio of the tumor area to the abdominal area in a preoperative single horizontal computed tomography slice (T/A ratio), were investigated in both groups.

RESULTS

The two groups were not different in age, body weight, tumor laterality, sex, or histological distribution. The T/A ratio in the ruptured group was significantly higher than that in the non-ruptured group. Receiver operating characteristic curve analysis identified a discriminative value for a T/A ratio >0.5.

CONCLUSION

The T/A ratio can be a predictive factor for intraoperative tumor rupture of Wilms tumor.

Anaplastic histology Wilms' tumors registered to the Japan Wilms' Tumor Study Group are less aggressive than that in the National Wilms' Tumor Study 5

PURPOSE

To evaluate the clinical features and treatment results of anaplastic histology (AH) Wilms' tumor (WT) patients registered in the Japan Wilms' Tumor Study (JWiTS) group to elucidate the clinical characteristics of AH in the Japanese population.

PATIENTS AND METHODS

Of 344 WT patients who were enrolled in JWiTS between 1995 and 2013, 17 had AH. Treatment using the JWiTS protocols was similar to the fifth National Wilms' Tumor Study 5 (NWTS-5) protocols. Clinical characteristics and mutation status of TP53 gene were evaluated and compared with those in NWST-5 study.

RESULTS

AH incidences in JWiTS were 4.9 %, lower than that in NWTS-5. Seven tumors had focal AH and 10 had diffuse AH. Clinical stages of AH patients were stage I in seven, stage II in three, stage III in five, stage IV in one and unknown in one. Four-year event-free survival and overall survival rates were 90.9 and 86.7 %, respectively. Two patients with diffuse AH and none with focal AH had TP53 mutation.

CONCLUSION

Japanese patients presented with higher incidence, earlier stages and may have better outcomes than American patients, indicating a possible biological heterogeneity of AH WT. Further analysis is necessary to elucidate the different characteristic of AH WT between Japanese and American populations.

Wilms tumor: Successes and challenges in management outside of cooperative clinical trials

OBJECTIVE/BACKGROUND

Management of Wilms tumor (WT) in children depends on a multidisciplinary approach to treatment, and outcomes have significantly improved as reported by cooperative group clinical trials. Here, we review the clinical outcomes of patients with WT and identify challenges and barriers encountered in multidisciplinary management outside of cooperative clinical trials.

METHODS

We retrospectively reviewed the clinical records of 35 children with WT treated between April 2002 and June 2013 at the Children's Cancer Institute in Lebanon.

RESULTS

Upfront resection was performed in 23 cases. Biopsies were performed for Stage V tumors (n=4), those with unresectable tumors or inferior vena caval thrombus (n=5), and patients who had partial surgery performed elsewhere prior to presentation (n=2). One patient died due to toxicity prior to surgery. The tumor was Stage I in eight patients, Stage II in five patients, Stages III and IV in nine patients each, and bilateral (Stage V) in four patients. Adherence to The National Wilms Tumor Study-5 recommendations was adequate. At the time of analysis, 30 patients were free of disease and four patients had relapse-all having metastatic disease initially.

CONCLUSION

The National Wilms Tumor Study-5 therapy resulted in favorable outcomes in children with nonmetastatic Wilms tumor in the setting of a multidisciplinary approach to therapy and resolution of financial barriers to medical care. Upstaging due to prior intervention and lung radiation therapy to all those with computed tomography-detected lung nodules may both have resulted in overtreatment of a subset of patients. Finally, the relatively high incidence of bilateral tumors suggests the need for further genetic and molecular studies in this patient population.

Management of pediatric renal tumor: Past and future trials of the Japan Wilms Tumor Study Group

The Japan Wilms Tumor Study group (JWiTS) was founded in 1996 to improve outcomes for children with renal tumor in Japan, and a nationwide multicenter cooperative study was initiated thereafter. JWiTS-1 (1996-2005) was analyzed, and JWiTS-2 (2005-2014) is now under analysis; the following problems have been identified and used to decide future study protocol: (i) there has been a decline in survival rate for patients with rhabdoid tumor of the kidney (RTK) and new treatment strategies are required; (ii) the survival rate for bilateral Wilms tumors (BWT) has improved, but results for renal preservation are unsatisfactory; (iii) the prognosis of stage IV favorable nephroblastoma is very good, suggesting that the current protocols provide overtreatment, particularly for patients with lung metastasis; and (iv) no effective biological risk factors exist for predicting the outcome of Wilms tumor, and a study of the genetic changes of these tumors is necessary to determine biological markers for use in risk classification. To solve these issues, the development of a new risk classification of pediatric renal tumors is required. In addition, different study protocols should be developed according to the risk-based classification of the patients. Further, a new study protocol for BWT began in 2015, and new study protocols are being prepared for RTK, and for Wilms tumor with lung metastasis. In addition, an analysis of biological markers with regard to risk classification is to be performed. Furthermore, to create new protocols for patients with rare renal tumors, international collaboration with Children's Oncology Group and International Society of Pediatric Oncology is necessary.

Clear cell sarcoma of the kidney with calcification and a novel chromosomal abnormality: a case report

A 9-year-old male presented with a renal tumor that showed a cystic structure with calcification on computed tomography. A pathological analysis of the resected tumor suggested clear cell sarcoma of the kidney (CCSK). Thus, this patient suffered atypical CCSK with significant calcification and gross necrosis. A novel chromosomal abnormality was also identified in the tumor.

Consistent in-frame internal tandem duplications of BCOR characterize clear cell sarcoma of the kidney

Clear cell sarcoma of the kidney (CCSK) is one of the major pediatric renal neoplasms, but its associated genetic abnormalities are largely unknown. We identified internal tandem duplications in the BCOR gene (BCL6 corepressor) affecting the C terminus in 100% (20/20) of CCSK tumors but in none (0/193) of the other pediatric renal tumors. CCSK tumors expressed only an aberrant BCOR allele, indicating a close correlation between BCOR aberration and CCSK tumorigenesis.

Clear cell sarcoma of the kidney distinguished from synovial sarcoma using genetic analysis: a case report

Background

The most common pediatric renal neoplasm is Wilms tumor, but clear cell sarcoma of the kidney or synovial sarcoma of the kidney are also sometimes encountered. Accurate pathological diagnosis is important, because adjuvant therapies including chemotherapy and radiotherapy differ according to the pathological type.

Case presentation

A 9-year-old boy presented with a headache, and ultrasonography, computed tomography, and magnetic resonance imaging revealed a heterogeneous enhancement of soft tissue originating from the upper pole of the left kidney, measuring approximately 11.0 × 10.0 × 8.0 cm. A left radical nephrectomy was performed using an intraperitoneal approach through an anterior subcostal incision. Pathological examination suggested clear cell sarcoma of the kidney or synovial sarcoma of the kidney based on morphological and immunohistological features. Using genetic analysis, a final diagnosis of spindle cell pattern clear cell sarcoma of the kidney was made based on the absence of the SYT-SSX fusion gene. After adjuvant chemo-radiotherapy was administered, no recurrence or metastasis has been identified as of 60 months postoperatively.

Conclusion

In this case, it was difficult to discriminate clear cell sarcoma of the kidney from synovial sarcoma of the kidney based on histopathological examination alone, and genetic analysis was required. Accurate pathological diagnosis of pediatric renal tumor is important for determining optimal treatment and preventing recurrence and metastasis.

A high incidence of WT1 abnormality in bilateral Wilms tumours in Japan, and the penetrance rates in children with WT1 germline mutation

Background:

Bilateral Wilms tumours (BWTs) occur by germline mutation of various predisposing genes; one of which is WT1 whose abnormality was reported in 17–38% of BWTs in Caucasians, whereas no such studies have been conducted in East-Asians. Carriers with WT1 mutations are increasing because of improved survival.

Methods:

Statuses of WT1 and IGF2 were examined in 45 BWTs from 31 patients with WT1 sequencing and SNP array-based genomic analyses. The penetrance rates were estimated in WT1-mutant familial Wilms tumours collected from the present and previous studies.

Results:

We detected WT1 abnormalities in 25 (81%) of 31 patients and two families, which were included in the penetrance rate analysis of familial Wilms tumour. Of 35 BWTs from the 25 patients, 31 had small homozygous WT1 mutations and uniparental disomy of IGF2, while 4 had large 11p13 deletions with the retention of 11p heterozygosity. The penetrance rate was 100% if children inherited small WT1 mutations from their fathers, and 67% if inherited the mutations from their mothers, or inherited or had de novo 11p13 deletions irrespective of parental origin (P=0.057).

Conclusions:

The high incidence of WT1 abnormalities in Japanese BWTs sharply contrasts with the lower incidence in Caucasian counterparts, and the penetrance rates should be clarified for genetic counselling of survivors with WT1 mutations.

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.

Wilms' tumor: a 24-year retrospective study from a single center

Medical records of 71 children with Wilms' tumor at Sisli Etfal Education and Research Hospital between 1990 and 2014 were reviewed. Mean age at diagnosis was 3.11 years (2 days-7 years). Male to female ratio was M/F = 6/10. The incidence of associated anomaly was 16.9%. Clinical manifestations included abdominal mass (89%), hematuria (30%), hypertansion (25%), abdominal pain (15%), fever (5%), restlessness (2%), weight loss (2%), varicocele (1%). Ultrasound (USG) was the most often initial study in a child presenting with abdominal mass. Doppler USG was also made to evaluate the inferior vena cava (IVC) for the presence of tumor extension in children with renal mass. The left kidney was affected in 33 patients (46.5%), the right was affected in 31 patients (43.7%). Two patients was extrarenal (2.8%). And 5 patients (7.04%) were bilateral on the presentation. Preoperative chemotheraphy was done in 14 cases. In 63 patients with unilateral Wilm tm, unilateral radical nefrectomy is performed. In one patient with solitary kidney, nephron sparing surgery (NSS) is performed. In 3 patients with bilateral tm NSS is performed and in 2 patients with bilateral Wilms' tm NSS is performed in one side and nefrectomy on the other side. Out of 71 Wilms tumor (WT) patients, 17 of them has been out of our follow. And 4 of them are died. Ten of them has metastases. Forty children are under follow with no metastases. Patients with WT needs a multimodal, multidisiplinary treatment with the cooperation of pediatric oncologist and pediatric surgeon and needs close follow-up.

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

BACKGROUND

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

PROCEDURE

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

RESULTS

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

CONCLUSIONS

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

Social and biological factors influencing the outcomes of children with Wilms tumors in Kenya and other Sub-Saharan countries

Wilms tumor (WT) is a common pediatric solid tumor, and the 5-year event-free survival rate of patients with this tumor has reached 85-90% in developed countries, whereas those in developing countries were reported to be less than 50%. To overcome these disparities, physicians and investigators in developed and developing countries are currently performing research with the aim of the better management of children with WT in Kenya and other Sub-Saharan countries. Axt and colleagues published a study that increased understanding of clinicopathology of WT in Kenya on the basis of a comprehensive web-based WT registry. The study revealed that patients enrolled in the National Health Insurance Fund (NHIF) showed better completion rate of therapy and better event-free survival than those not enrolled, indicating insufficient health coverage for those not enrolled in the NHIF. Approximately 20-30% of Kenyan population is estimated to be covered by some forms of health insurance, mostly by the NHIF. This could be improved through various approaches. The report described that 2-year event-free survival rate was 52.7% for all patients, although loss to follow up was 50%; the findings indicate large problems both in the study results and also in the completion of treatment. It is crucial to determine at which point patients stopped their treatment and why. The development of standardized treatment protocol for WT is an urgent agenda. We hope that researchers in developed countries and health providers in Kenya can work together in future to conquer disparities in the outcomes of children with WT.

Anaplastic sarcoma of the kidney: case report and literature review

Anaplastic sarcoma of the kidney (ASK) is a relatively newly recognized pediatric renal tumor. The present patient, a 13-year-old boy with a large renal mass, underwent surgery. Pathological findings showed proliferation of short spindle-shaped cells with anaplastic features including multiple foci in hyaline cartilage. Complex chromosomal abnormalities were detected in the tumor cells. Postoperative chemotherapy with the regimen for Ewing's sarcoma achieved complete remission but the tumor recurred and the patient died during re-induction chemotherapy. Autopsy indicated the cause of death as duodenal hemorrhage. Because there were no viable tumor cells, the recurrent tumor was considered to have been completely cured by chemotherapy. ASK is a very rare tumor, of unknown pathogenesis, and no standard treatment has yet been established, but the tumor cells may be responsive to chemotherapy. Further study is needed to establish the optimal treatment strategy.

The prognostic significance of blastemal predominant histology in initially resected Wilms' tumors: a report from the Study Group for Pediatric Solid Tumors in the Kyushu Area, Japan

BACKGROUND AND PURPOSE

The strategy used to treat pediatric renal tumors in Japan is based on the Japanese Wilms' Tumor Study (JWiTS) protocol, which was based on the National Wilms' Tumor Study (NWTS)-5 regimen. The regimen is characterized by an initial radical operation, followed by adjuvant chemotherapy and radiotherapy. Concerning the histological classification, a new classification based on the International Society of Pediatric Oncology (SIOP) classification was used beginning in 2008. The main points of revision are that the "blastemal predominant type" was classified as an independent category in the Wilms' tumor subtypes. The purpose of this study was to analyze the biological characteristics from the standpoint of the newly established histological classification.

MATERIALS AND METHODS

From 1971 to 2005, 174 cases of Wilms' tumors treated with an initial operation followed by adjuvant therapy were re-evaluated by the new histological classification. Histologically, all these materials showed no secondary changes associated with adjuvant therapy.

RESULTS

According to the new classification, Wilms' tumors were classified into four subtypes, including the mixed type (n=112), epithelial type (n=17), mesenchymal type (n=15), and blastemal predominant type (n=26). The 5 year overall survival rates were as follows; mixed type (90.1%), epithelial type (100%), mesenchymal type (93.3%), and blastemal predominant type (65.4%).

CONCLUSION

The patients with blastemal predominant tumors demonstrated a significantly worse prognosis compared with those of other subtypes. The treatment strategy of blastemal predominant category should be distinguished from the other favorable subtypes.

Relapse of unilateral favorable histology Wilms' tumor: significant clinicopathological factors

PURPOSE

To evaluate the clinicopathological features that indicate relapse and suggest a new risk based therapeutic strategy for unilateral Favorable Histology Wilms Tumor (FH-WT).

MATERIALS & METHODS

Thirty-three patients with unilateral WT were treated in two institutions between 1986 and 2010. Twenty-eight patients with FH-WT received primary nephrectomy according to the National Wilms' Tumor Study (NWTS) or the Japanese Wilms' Tumor Study (JWiTS) protocol. Retrospective analyses of the non-relapsed group (n=23) and the relapsed group (n=5) compared age, gender, tumor laterality, tumor weight, initial tumor stage, known histological subtype, chemotherapy (2 or 3 drugs), and any irradiation delivered. Stages and histological subtypes of the tumors were re-evaluated according to the Japanese staging system.

RESULTS

Five of the twenty-eight tumors relapsed, and one patient died. The initial staging (P=0.029) and the histological subtype (P=0.003) were the only factors indicating relapse. Nine of the twenty-three tumors were histologically classified as blastemal predominant subtype (BPT-WT). Five relapsed.

CONCLUSION

According to the basic Japanese therapeutic strategy, all patients underwent a primary nephrectomy before chemotherapy. This study suggests that the histological subtype pre-treatment "BPT-WT" should be included as a strong indicator of poor prognosis. Such patients should be treated as a high-risk group.

Methylation of the RASSF1A promoter is predictive of poor outcome among patients with Wilms tumor

BACKGROUND

Wilms tumor (WT) has a survival rate of 90% following multimodality therapy. Nevertheless, there are some groups of patients with event-free survival rates less than 75%. In addition to clinical prognostic factors, loss of heterozygosity at 1p and/or 16q has been used to determine treatment intensity. However, the incidence of this abnormality is low, and new biomarkers are still needed.

PROCEDURE

We analyzed methylation status of three tumor suppressor genes; Ras-association domain family 1 protein, isoform A (RASSF1A), DCR2, and CASP8, in 84 WTs using conventional methylation-specific PCR (cMSP), and the results were correlated with outcome. Furthermore, we analyzed the methylation status of RASSF1A by quantitative MSP (qMSP) in 171 WTs, and evaluated clinical and genetic differences between the methylated and unmethylated tumors.

RESULTS

RASSF1A was the most frequently methylated gene identified by cMSP, and associated with a poor outcome. Patients with a RASSF1A-methylated tumor had shorter overall and event-free survival periods (P = 0.043 and 0.018, respectively), when a cut-off value of 7% by qMSP was used. The methylation was more frequent in tumors of older children than younger children (P < 0.001), and in advanced-stage tumors than early stage tumors (P = 0.001). However, multivariate analysis could not confirm the prognostic significance of RASSF1A methylation, possibly because of a small number of advanced stage tumors examined. RASSF1A methylation was correlated with LOH at 1p and/or 16q (P = 0.017), but not with WT1 abnormality, suggesting the methylation and LOH to involve the same tumorigenic pathway.

CONCLUSIONS

The methylation status of RASSF1A might be a novel biomarker to predict outcome of WT patients.

Clear cell sarcoma of the kidney: a review

Clear cell sarcoma of the kidney (CCSK) is a rare renal tumour that is observed most often in children under 3years of age. Only a few large series of CCSK have been reported and patients with CCSK are often included among patients with other types of childhood renal tumours. The purpose of this paper is to review the published series and case reports of CCSK and to create an up-to-date overview of clinical and histological features, genetics, treatment, and outcome.

The clinical course in pediatric solid tumor patients with focal nodular hyperplasia of the liver

BACKGROUND

Focal nodular hyperplasia (FNH) of the liver is a rare benign lesion that may be related to the vascular and hepatic damage induced by completion of tumor therapy and a reaction to localized vascular abnormality. The aim of this study was to analyze the clinical course in pediatric solid tumor patients with FNH.

METHODS

We analyzed thirty-two patients with pediatric solid tumors who received multiagent chemotherapy (15 advanced neuroblastomas, 7 hepatoblastomas, 5 rhabdomyosarcomas, 2 nephroblastomas, 1 rhabdoid tumor of the kidney, 1 clear cell sarcoma of the kidney and 1 pancreatoblastoma). All of them had been previously treated at our hospital, and have been alive for over 3 years without recurrence.

RESULTS

FNH lesions were discovered in three (9.4%) of 32 patients, and were neuroblastoma (NB) stage 4. All 3 patients received induction chemotherapy and high-dose alkylating agents, and developed grade 3 (National Cancer Institute Common Toxicity Criteria; NCI-CTC) liver dysfunction during completion of tumor therapy without veno-occlusive disease. Two of the 3 patients received the same induction chemotherapy and high doses of alkylating agents with total body irradiation for cytoreductive agents prior to peripheral blood cell transplantation. FNH lesions in both female patients who received estrogen replacement therapy after completion of tumor therapy have expanded and are increasing.

CONCLUSION

FNH appears to be a late complication of iatrogenic disease in NB stage 4 patients. The therapeutic agents for NB stage 4 and estrogen replacement therapy should be considered as risk factors for the development of FNH.

Clear cell sarcoma of the kidney in children: experience in a developing country

INTRODUCTION

Clear cell sarcoma of the kidney (CCSK) is a rare tumour comprising 4% of primary renal tumours in children. It has a unique constellation of chromosomal and molecular features and should no longer be viewed as an unfavourable histological variant of Wilms tumour. Little is known of its clinical presentation and pathological profile in children living in a developing country.

AIM

To describe the clinical and pathological features of CCSK in children in our practice and to identify factors contributing to poor patient outcomes.

METHOD

A retrospective review of patients with a confirmed diagnosis of CCSK who presented for treatment at a single institution between 1990 and 2008.

RESULTS

14 patients fulfilled the inception criteria. They represented 4% of 356 patients presenting with primary renal tumours during the review period. Clinical and radiological features were indistinguishable from Wilms tumour. Tumours were large (Mean mass 1.4 kg; median 0.9 kg) and metastases were common (42%). Lung and lymph node metastases were more common than skeletal disease. Co-morbidity, particularly hypertension (64%) was common. Initial diagnosis by needle biopsy was correct in only two of seven patients (29%) leading to inappropriate neoadjuvant chemotherapy. Overall survival is poor with 57% of patients alive and disease free from 1 to 7 years off treatment.

CONCLUSION

In a developing country, CCSK is rare and clinically and radiologically indistinguishable from Wilms tumour. Associated hypertension is common. Pretreatment diagnosis is difficult and sampling errors using needle biopsies may be unavoidable. Treatment results are poor and, given the propensity for late recurrence in CCSK, may not be sustained.