A scoring system for Wilms' tumour: pathological study of the second Medical Research Council (MRC) trial

Stage I epithelial or stromal type Wilms tumors are low risk tumors: An analysis of patients treated on the SIOP-WT-2001 protocol in the UK-CCLG and GPOH studies (2001-2020)

BACKGROUND

Patients treated with preoperative chemotherapy with stage I intermediate-risk Wilms tumor (IR-WT) represent the largest group of patients with Wilms tumor (WT), and they have excellent outcomes.

METHODS

The authors performed a retrospective analysis of patients with stage I epithelial (ET-WT) or stromal type WT (ST-WT) treated pre- and postoperatively according to the International Society of Paediatric Oncology-WT-2001 protocol in the UK Children's Cancer and Leukaemia Group and Gesellschaft für Pädiatrische Onkologie und Hämatologie groups' participation in the relevant WT trials and studies (2001-2020).

RESULTS

There were 880 patients with stage I IR-WT, including 124 with ET-WT, 156 with ST-WT, and 600 with other IR-WT (oIR-WT). Patients with stage I ET-WT or ST-WT were significantly younger than patients with oIR-WT, represented a large proportion of stage I WTs in their groups, and tumors showed poor histologic response to preoperative chemotherapy. The 5-year event-free survival (EFS) estimates for patients with stage I ET-WT (96.8% ± 1.8 SE) or ST-WT (96.8% ± 1.6 SE) were significantly better than for patients with oIR-WT (90.3% ± 1.3 SE) (p = .014 and p = .009, respectively). A multivariate analysis showed that histologic type (ET-WT or ST-WT) remained a significant factor for EFS when adjusted for age and gender (p = .032 and p = .022, respectively). In both groups, relapses occurred in 3.2% of patients, and the overall survival was 99.2%.

CONCLUSIONS

The results suggest that stage I ET-WT or ST-WT could be regarded as low-risk WT, for which omission of postoperative chemotherapy should be considered.

PLAIN LANGUAGE SUMMARY

Patients with pretreated intermediate-risk Wilms tumor (WT) represent the largest group of patients with WT. This study reports the outcomes of patients with stage I epithelial type (ET-WT) or stromal type WT (ST-WT). These patients were significantly younger and had a larger proportion of stage I cases than patients with other intermediate-risk WT (oIR-WT). The event-free survival for patients with stage I ET-WT and ST-WT was significantly better than for patients with oIR-WT. Rare relapses were curable resulting in 99.2% overall survival.

Is there a socioeconomic variation in survival from renal tumours in children and young people resident in northern England (1968-2012)?

BACKGROUND

Despite strong evidence of a social gradient in cancer survival among UK adults, studies in children and young people remain inconclusive and have not included renal tumours. This study investigated the relationship between socioeconomic status and survival from renal tumours among children and young people.

PROCEDURE

Kaplan-Meier estimation and Cox regression were used to analyse survival for all 209 renal tumours in children and young people (0-24 years) diagnosed 1968-2012 and registered by a specialist population-based registry. Sociodemographic and clinicopathologic variables, including paternal occupation at birth, were also analysed.

RESULTS

No significant disparity in overall renal tumour and Wilms tumour (WT) survival was observed according to paternal social class [p=0.988 and 0.808, respectively]. The strongest predictor of survival was stage, with late stage (III-IV) disease having a 4-fold higher risk of death compared to early stage (I-II) disease [p<0.001]. Similarly, high mortality-risk was seen for late stage WT in children aged 0-14 years (Hazard Ratio=6.37; 95% CI=2.60-15.59).

CONCLUSIONS

This study did not detect a significant social gradient in renal tumour survival. The identification of tumour stage as a strong predictor of survival irrespective of age, necessitates the development of appropriate public health interventions that target early diagnosis and treatment.

Stromal and epithelial predominant Wilms tumours have an excellent outcome: the SIOP 93 01 experience

BACKGROUND

Wilms tumour (WT) has various subtypes that are correlated with prognosis and require distinct therapy. Stromal predominant (SpWT) and epithelial WT (EpWT) have previously been associated with a good outcome. The current analysis describes the outcome and (tumour) characteristics of all patients with SpWT, EpWT, including highly differentiated epithelial type (HDET), treated according to the International Society of Pediatric Oncology (SIOP) 93-01 study.

PROCEDURE

All children older than 6 months and below 18 years of age with localized or metastatic WT and intermediate risk (IR) histology or HDET treated with pre-operative chemotherapy were included in the present analysis.

RESULTS

A total of 1,389 eligible patients had IR or HDET histology: 1% HDET, 4% EpWT, 10% SpWT, and 85% other IR. For EpWT/HDET, 93% had stage I/IIN-, 5-year EFS was 90.2% and overall survival of (OS) 98.4%, as compared to 84.0% and 92.5% in other IR histology (NS). Stage I EpWT/HDET had a significant better outcome than stage I of other IR. In SpWT 82% of cases had stage I/IIN-; 5-year EFS was 94.3% and OS 99.2%, significantly better compared to other IR histology. All patients with stage I are alive (2/149 relapses); 3/52 stage IIN-, 2/21 stage IIN+/III, and 6/12 stage IV patients relapsed (1 deceased per stage group).

CONCLUSIONS

The good outcome for EpWT and SpWT generally is very good which may be related to low age and low stage in most cases. A reduction of treatment intensity and/or duration may be justified especially for low stage SpWT that has an EFS close to 100%.

Increased serum VEGF in 13 children with Wilms' tumour falls after surgery but rising levels predict poor prognosis

Vascular endothelial cell growth factor (VEGF, a potent endothelial cell mitogen in vitro) may be important in tumour development and its spread in vivo. In this preliminary study, we tested the hypotheses that (i) raised serum levels in Wilms' tumour fall after surgery, and (ii) rising levels predict adverse outcome. Serum VEGF was measured (ELISA) in 13 children about to undergo surgery, and serially on the following day, a week later, and finally 3-6 months after surgery. A simple follow-up at 6 months was also performed. The control group was 60 healthy adults. Before surgery, the median (inter-quartile range) VEGF in the children was 20 ng/ml (10.4-70.5) and was 1 ng/ml (0.5-4.0) in the adults. This difference is statistically highly significant (P=0.0001). After surgery, levels in the children fell significantly to 1.3 ng/ml (0.5-7.95) the following day and to 1.9 ng/ml (0.5-5.0) the following week (P<0.001, ANOVA). Six months after surgery, three of the children had died. A level of >10 ng/ml measured 3 months after surgery correctly identified all three deaths: levels were 1.3 ng/ml (0.5-1.9) in the survivors and were 20.0 ng/ml (15-104) in those who died. These data indicate a rapid reduction in raised VEGF following surgery for Wilms' tumour, but that rising levels predict poor prognosis.

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

BACKGROUND

Histologic subtypes of standard histology Wilms' tumor (WT) and the effect of preoperative therapy on their clinical and histologic features, deserve to be analysed in respect to outcome to find an adequate baseline for therapy.

PATIENTS AND METHODS

The German Society of Paediatric Oncology & Haematology enrolled patients from January 1989 to March 1994 for therapy according the International Society of Paediatric Oncology trial & study 9. Standardised preoperative therapy with dactinomycin and vincristine for 4-8 weeks was generally applied in patients between 0.5 and 16 years with localized renal tumors and imaging typical for WT. In 99.5% of cases representative material was sent for review to the Kiel Paediatric Tumour Registry. For prospective subtyping of 329 WT (258 after preoperative therapy, 71 with immediate surgery) modified Beckwith & Palmer criteria were used. Reduction in volume measured by imaging prior to chemotherapy and surgery was used to assess response (poor response: reduction < 40%; good response: reduction > or = 40%).

RESULTS

There were 39% of patients treated with immediate surgery and 12.4% of patients with preoperative therapy in the age group up to 12 months. The difference in age (P = 0.022) was linked with different amounts of epithelial WT (15.5% vs. 3.1%), median age: 0.58 and 0.93 years. Due to the effect of chemotherapy the amount of other WT changed: stromal 0% to 14%, mixed 45.1% to 29.4%, blastemal 39.4% to 9.3%). After preoperative therapy 37.6% of WT were predominantly regressive, 6.6% completely necrotic. Poor response was frequent in differentiated WT (86% of stromal, 75% of epithelial WT) but none relapsed. In the other WT with viable tumor left after preoperative therapy > 70% had good response, poor response was a risk factor (P = 0.0057).

CONCLUSIONS

Subtyping according modified Beckwith & Palmer can be used in WT after preoperative therapy to stratify postoperative therapy in future. A milder therapy could be tested in differentiated WT at low stages and an intensified in the others with viable tumor left and poor response, i.e., mainly blastemal WT.

Thirty-year population-based review of childhood renal tumours with an assessment of prognostic features including tumour DNA characteristics

We have reviewed all paediatric kidney tumours seen in the West Midlands Health Authority Region over a 30-year period. There were 205 cases confirmed after a review of the pathology by three paediatric pathologists. Seven were cases of bone metastasising renal tumour (clear cell sarcoma), 5 were rhabdoid tumours, 2 were renal cell carcinomas, and 13 were mesoblastic nephromas. In 3 cases, it was not possible to define further the histological diagnosis. The remaining 175 cases were considered to be Wilms' tumour (86%), which is equivalent to an incidence of 5.7/10(6)/year. In the cases of Wilms' tumour, there were 91 boys and 84 girls (1.1:1). The majority of patients were Caucasian with only 7% of non-Caucasian origin. At presentation, 78% of the patients were less than 5 years old. All of these patients except 9 had surgery as part of their treatment, 154 children had total nephrectomy, 3 had partial nephrectomy, and 9 had other surgical procedures. The majority also received chemotherapy and radiotherapy. Sex, chemotherapy, and stage all had prognostic significance in univariate analysis. The actuarial survival at 10 years increased from 17% for patients treated in the first decade of the study to 78% for patients treated in the third. DNA characteristics were investigated using flow cytometry in paraffin-embedded material and adequate information was obtained in 73 cases of Wilms' tumour. Only 7 had aneuploid tumours. Univariate survival analysis of these 73 results showed that stage, sex, the percentage of cells in the synthetic phase and the proliferative index from the DNA investigations had predictive value.

Malignant renal tumors of childhood

The prognosis in nephroblastoma (Wilms' tumor) has been improved considerably by treatment protocols combining surgery, chemotherapy, radiation therapy, and, in some clinical trials, pre-operative chemotherapy. Cure is now achieved in most patients. All clinical trials have employed treatment strategies tailored to the individual risk of the patient, including the histological subtype of the tumor. In the National Wilms' Tumor Study (NWTS) of the United States these subtypes have been divided into two groups of tumors according to their "favorable" or "unfavorable" histology. At the Kiel Pediatric Tumor Registry we have devised a system which distinguishes three groups of tumors classified according to prognosis. The first group includes tumors with a favorable prognosis, even if only surgery is performed. These comprise congenital mesoblastic nephroma (CMN) and cystic, partially differentiated nephroblastoma (CPDN). The second group consists of tumors posing an intermediate risk, such as typical nephroblastoma and its histological variants characterized by variations in the relative proportions of the histological components. Fetal rhabdomyomatous nephroblastoma (FRN) is also included in this group. The third group comprises tumors of high risk such as anaplastic nephroblastoma, clear cell sarcoma of the kidney (CCSK), and malignant rhabdoid tumor of the kidney (MRTK). Since histological diagnosis plays a crucial role in the assignment of a patient to a particular type of treatment protocol, knowledge of the histological appearance of the various tumor types both with and without preoperative treatment is of utmost importance.

International variations in the incidence of childhood renal tumours

The International Agency for Research on Cancer has coordinated a worldwide study of childhood cancer incidence, with data from over 50 countries. We present here the results on renal tumours. Wilms' tumour was the most common malignant kidney tumour in all regions. It is sometimes considered to be an 'index cancer of childhood' but it is clear from the present study that there is at least a threefold difference in incidence between the age-standardised annual rates of over 10 per million in the Black populations in the United States and Nigeria and those of around three per million in several East Asian populations. In White Caucasian populations, Wilms' tumour had an annual incidence of 6-9 per million, accounting for 5-7% of all childhood cancer. It was almost everywhere equally common in boys and girls, but the sex ratio in East Asia was M/F = 1.4:1. Age distributions were similar among White Caucasian and Black populations, with the peak incidence in the second year of life. In East Asia, however, 25-40% of the total incidence occurred in infants aged under 1 year, compared with around 15% in many Western series. Other studies have shown that, in the United States, Wilms' tumour has a lower incidence among Asian children than among Whites or Blacks and tends to occur at a younger age. The variation in patterns of incidence of Wilms' tumour along ethnic rather than geographical lines suggests that genetic predisposition is important in its aetiology. Renal carcinoma in childhood is rare throughout the world, with little sign of international variation. It accounted for a higher proportion of childhood renal tumours in East Asia but this was attributable to the lower incidence of Wilms' tumour in that region.

Sera of children with renal tumours contain low-molecular-mass hyaluronic acid

The molecular mass of hyaluronic acid (HA) rather than its serum concentration alone may be a hallmark of certain types of malignancy. A radiometric assay was used to measure HA levels in 35 children with renal tumours [33 Wilms' tumours and 2 bone metastasizing renal tumours of childhood (BMRTC)] and 20 normal siblings of children with cancer. The HA level in the sera of normal children was barely detectable and had a molecular mass of 1-5 x 10(5). In both Wilms' and BMRTC patients, very high levels of HA were found in preoperative serum samples; these fell dramatically following surgical excision of the tumours. A novel finding of our study was the presence of low-molecular-mass HA (similar to the angiogenic fragments of HA) in the sera of BMRTC patients. In contrast, high-molecular-mass HA (which is not angiogenic) was found in the sera of Wilms' patients (2 x 10(6) kDa). Following surgery in BMRTC patients, not only did serum HA levels fall to a value within normal ranges, but also the HA which remained was of high molecular mass.

Prognostic relevance of DNA content in childhood renal tumours

The DNA content of paraffin embedded tumour specimens from 100 children with kidney tumours was studied by flow cytometry. Data of adequate quality were obtained from 93 cases comprising 67 Wilms' tumours with a favourable histology (FH), 12 Wilms' tumours with unfavourable histology (UH) (pleomorphic), 8 bone-metastasising renal tumours of childhood (BMRTC) and 6 rhabdoid renal tumours. Only 4.5% FH compared with 75% UH Wilms' were aneuploid (P less than 0.001). Although BMRTC and rhabdoid tumours are associated with poor prognosis, there were no examples of aneuploidy in these tumours. The proliferation index was found to be of no prognostic value. Staging and ploidy were not correlated with each other in any of the various histological types of renal tumours studied.

A monoclonal antibody stains blastemal but not tubular components of Wilms' tumour

The monoclonal antibody PAL-E is specific for endothelial cells in a wide variety of normal and tumour tissue. In normal kidney, PAL-E reacts exclusively with the endothelium of non-glomerular blood vessels. In Wilms' tumour, binding of PAL-E was not restricted to the endothelium; staining of blastemal cells was observed in seven out of eight cases examined. Mesenchymal and tubular components, if present in Wilms' tumour, were negative. In contrast, a monoclonal antibody to Factor VIII-related antigen (RFF-8-R-1) bound only to endothelial cells in these tumours. In fetal kidney, PAL-E binding showed a wider distribution than in adult kidney and both stromal and glomerular capillaries were stained. Tubules and non-endothelial stromal cells were negative. These results indicate that the reactivity of the monoclonal antibody, PAL-E, is not restricted to cells of endothelial origin in all tissues. The implications of these findings for the differentiation of Wilms' tumour are discussed.

Study of childhood renal tumours using peroxidase conjugated lectins

Six peroxidase conjugated lectins were used to compare their ability to bind to formalin fixed paraffin embedded tissue sections of childhood renal tumours (Wilms' tumour, mesoblastic nephroma, renal carcinoma, rhabdoid renal tumour, and bone metastasising renal tumour of childhood (BMRTC) with fetal and normal children's kidney. Lectins were found to be helpful in the differential diagnosis of renal tumours. Another important finding was that the mesenchyme of renal tumours showed differences in its reactivity among various types of kidney tumours. The results of lectin binding were not helpful in establishing the origin of kidney tumours.

Study of childhood renal tumours using antisera to fibronectin, laminin, and epithelial membrane antigen

Using a peroxidase-antiperoxidase staining procedure, formalin fixed paraffin embedded sections of fetal and normal kidney; benign (mesoblastic nephroma); and malignant tumours (Wilms' tumour, clear cell renal carcinoma, rhabdoid renal tumour, and bone metastasising renal tumour of childhood (BMRTC] were examined for their reactivity with antisera to fibronectin, laminin, and epithelial membrane antigen. Mesoblastic nephroma contained fibronectin but no laminin. Most Wilms' tumours lacked both fibronectin and laminin; 50% of rhabdoid renal tumours were positive for fibronectin and laminin--rhabdoid tumours as recognised morphologically may, in fact, be two separate entities. BMRTC and clear cell renal carcinoma lacked both fibronectin and laminin. Epithelial membrane antigen was present in most of the tubular Wilms' tumour but absent in blastemal Wilms' tumours. The presence of epithelial membrane antigen in rhabdoid tumours was surprising, as histologically, this type of tumour shows no sign of epithelial differentiation. Epithelial membrane antigen antiserum stained clear cell renal carcinomas: epithelial membrane antigen is found in the distal and not the proximal tubules of fetal and normal kidneys. Thus an obvious interpretation is that clear cell renal carcinomas originate from distal rather than from proximal tubules, as has always been thought. On the basis of these results and data from other published findings some possible histogenetic origins of childhood renal tumours were proposed.

Papillary Wilms' tumour with carcinoma-like foci and renal cell carcinoma in childhood

Five cases of Wilms' tumour with prominent papillary formation and focal carcinoma-like epithelium are described. The morphology of these tumours is compared with a group of six renal cell carcinomas in childhood. A link between this type of nephroblastoma and renal carcinoma is suggested but pure renal carcinomas are considered to be a separate category. The biological behaviour of the papillary Wilms' tumours was found to be more aggressive than is generally believed. The course of the disease may be influenced by carcinoma-like structures although this fact is not definitely established. Staging seems to be more helpful in such patients as is the case with renal cell carcinomas. Further studies on this type of Wilms' tumour are needed to establish more consistent data.

Mesoblastic nephroma contains fibronectin but lacks laminin

Non-metastatic mesoblastic nephromas from four young children were shown to contain fibronectin but not laminin using an immunoperoxidase staining procedure. In contrast, one metastasising spindle celled sarcomatous tumour from a neonate was laminin positive. During embryogenesis primitive nephrogenic mesenchyme contains only fibronectin and no laminin; metanephric blastema (permanent kidney) is positive for laminin. The staining for fibronectin and laminin may help to ascertain the histogenesis of different types of renal tumour.

Childhood kidney tumours: in vitro studies and natural history

The growth patterns of mesoblastic nephroma, Wilms' tumour and bone metastasizing renal tumour of childhood (BMRTC) are distinct from one another and are therefore useful in distinguishing children's kidney tumours. Of the 3 tumour types only BMRTC was able to invade native collagen gels. Fibronectin was present in Wilms' tumour and mesoblastic nephroma, but absent from BMRTC. The readdition of fibronectin to fibronectin depleted tissue culture medium markedly reduced the ability of BMRTC to migrate into collagen gels. The significance of the results and their relevance to the natural history of these neoplasms is discussed.