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Background Our aim is to show whether the sentinel node procedure (SNP) is recommendable for pediatric patients with extremity rhabdomyosarcoma (RMS). Lymph node metastases are an important prognostic factor in pediatric patients with extremity RMS. Accurate nodal staging is necessary to treat the patient accordingly. An alternative to the current recommended lymph node sampling is the sentinel node procedure (SNP). Methods A systematic review was performed summarizing all published cases of SNP in addition to 13 cases from our hospital and 8 cases from two other hospitals that have not been published before. Results For all patients (n = 55), at least one SLN was identified, but the SNP technique used was not uniform. The SNP changed the nodal classification of eight patients (17.0%) and had a false-negative rate of 10.5%. Conclusions The SNP is recommendable for pediatric patients with extremity RMS. It can change lymph node status and can be used to sample patients in a more targeted way than nodal sampling alone. Therefore, we recommend use of the SNP in addition to clinical and radiological nodal assessment for pediatric patients with extremity RMS.

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.

Thymic tumors are epithelial tumors arising from the anterior mediastinum and constitute 0.2-1.5% of all adult malignancies but are exceptional in pediatric population. Thymic epithelial tumors (TETs) encompass a variety of histologic subtypes associated with different clinical outcomes. Due to its rarity in children, TETs' management requires a multidisciplinary approach. However, prognosis remains still poor, especially among patients with thymic carcinoma. This study presents the internationally recognized recommendations for the diagnosis and treatment of thymic tumors in children and adolescents, established by the European Cooperative Study Group for Pediatric Rare Tumors (EXPeRT) group within the EU-funded project Paediatric Rare Tumours Network - European Registry (PARTNER).

As part of the European Union-funded project designated Paediatric Rare Tumours Network - European Registry (PARTNER), the European Cooperative Study Group for Pediatric Rare Tumors (EXPeRT) is continuously developing consensus recommendations in order to harmonize standard care for very rare solid tumors of children and adolescents. This paper presents the internationally recognized recommendations for the diagnosis and treatment of sex cord stromal tumors (SCST). The clinical approach to sex cord stromal tumors of the testis (TSCST) and ovary (OSCST) depends on histological differentiation and tumor stage. Virtually all TSCSTs present as localized nonmetastatic tumors, with excellent prognosis after complete resection. In contrast, the prognosis of OSCSTs may be adversely affected by tumor spillage during surgery or presence of metastases. In these cases, cisplatin-based chemotherapy is recommended. Of note, some SCSTs may develop in the context of tumor predisposition syndromes, for example, DICER-1, so that specific follow-up is indicated. SCSTs should be diagnosed and treated according to standardized recommendations that include reference pathology, genetic testing for tumor predisposition syndromes in selected cases, and stratified adjuvant chemotherapy in patients with unfavorable risk profile. To ensure high quality of diagnosis and therapy, patients should be enrolled into prospective registries.

Patients with a Wilms tumor are often admitted to the hospital accidentally, with an abdominal mass causing asymmetry of the abdominal wall. Hypertension accompanying a Wilms tumor occurs in about 10–27% of children, but cardiomyopathy associated with a Wilms tumor is very rarely described. This publication presents a case of a 9-month-old girl with a bilateral Wilms tumor accompanied by dilated cardiomyopathy since her initial cancer diagnosis, as well as her off-protocol treatment. The severe condition of the child forced the application of off-protocol treatment, i.e., accelerated resection of a larger tumor, which enabled the improvement of heart performance and made subsequent therapy possible. In the course of the presented treatment, a gradual normalization of cardiac ventricular function and contractility was observed. In conclusion, a massive abdominal tumor associated with abdominal compartment syndrome compromised the functioning of the cardiovascular system in the young child. Therefore, earlier removal of Wilms tumors in patients with heart failure should be considered. This may result in the improvement of cardiovascular function and the possibility of further therapy.

PURPOSE To evaluate the impact of surgeon-assessed extent of primary tumor resection on local progression and survival in patients in the International Society of Pediatric Oncology Europe Neuroblastoma Group High-Risk Neuroblastoma 1 trial. PATIENTS AND METHODS Patients recruited between 2002 and 2015 with stage 4 disease > 1 year or stage 4/4S with MYCN amplification < 1 year who had completed induction without progression, achieved response criteria for high-dose therapy (HDT), and had no resection before induction were included. Data were collected on the extent of primary tumor excision, severe operative complications, and outcome. RESULTS A total of 1,531 patients were included (median observation time, 6.1 years). Surgeon-assessed extent of resection included complete macroscopic excision (CME) in 1,172 patients (77%) and incomplete macroscopic resection (IME) in 359 (23%). Surgical mortality was 7 (0.46%) of 1,531. Severe operative complications occurred in 142 patients (9.7%), and nephrectomy was performed in 124 (8.8%). Five-year event-free survival (EFS) ± SE (0.40 ± 0.01) and overall survival (OS; 0.45 ± 0.02) were significantly higher with CME compared with IME (5-year EFS, 0.33 ± 0.03; 5-year OS, 0.37 ± 0.03; P < .001 and P = .004). The cumulative incidence of local progression (CILP) was significantly lower after CME (0.17 ± 0.01) compared with IME (0.30 ± 0.02; P < .001). With immunotherapy, outcomes were still superior with CME versus IME (5-year EFS, 0.47 ± 0.02 v 0.39 ± 0.04; P = .038); CILP was 0.14 ± 0.01 after CME and 0.27 ± 0.03 after IME ( P < .002). A hazard ratio of 1.3 for EFS associated with IME compared with CME was observed before and after the introduction of immunotherapy ( P = .030 and P = .038). CONCLUSION In patients with stage 4 high-risk neuroblastoma who have responded to induction therapy, CME of the primary tumor is associated with improved survival and local control after HDT, local radiotherapy (21 Gy), and immunotherapy.

For decades, radiotherapy with two opposing photon beams has been the standard technique used to cover the flank target volume in paediatric patients with renal tumours. Nowadays, many institutes are implementing advanced radiotherapy techniques that spare healthy tissue. To decrease the radiotherapy dose to healthy structures while preserving oncological efficacy, the conventional approach of flank irradiation has been adapted into a guideline for highly conformal flank target-volume delineation by paediatric radiation oncologists and representatives of the International Society of Paediatric Oncology's Renal Tumour Study Group (SIOP-RTSG) board during four live international consensus meetings. The consensus was refined by delineation exercises and videoconferences by ten collaborating paediatric radiation oncologists. The final guideline includes eight chronological steps to generate the tumour bed and clinical, internal, and planning target volumes, and it describes the optional use of surgical clips to optimise treatment planning. This guideline will be added into the radiotherapy guideline of the UMBRELLA SIOP-RTSG protocol for paediatric renal tumours to improve international consistency of highly conformal flank target-volume delineation.

Introduction High-risk (HR) metastatic (stage IV) Wilms tumours (WTs) have a particular poor outcome. Methods Here, we report the results of HR (diffuse anaplastic [DA] or blastemal type [BT]) stage IV WT treated patients according to the HR arm in the SIOP2001 prospective study. Results From January 2002 to August 2014, 3559 patients with WT were included in the SIOP2001 trial. Among the 525 patients (15%) with metastatic WT, 74 (14%) had stage IV HR-WT. The median age at diagnosis was 5.5 years (range: 1.4–18.3). Thirty-four patients (47%) had BT-WT and 40 (53%) had DA-WT. Five-year event-free survival rates were 44 ± 17% and 28 ± 15% for BT-WT and DA-WT, respectively (p = 0.09). Five-year overall survival rates were 53 ± 17% and 29 ± 16% for BT-WT and DA-WT, respectively (p = 0.03). Metastatic complete response after preoperative treatment was significantly associated with outcome in univariate and multivariate analyses (hazards ratio = 0.3; p = 0.01). Postoperative radiotherapy of metastatic sites might also be beneficial. Forty-three of 74 patients experienced a relapse or progression predominantly in the lungs (80%). The median time to relapse/progression after diagnosis was 7.3 months (range: 1.6–33.3) and 4.9 months (range: 0.7–28.4) for BT-WT and DA-WT, respectively (p = 0.67). This is the first prospective evidence of inferior survival of stage IV BT-WT as compared with historical intermediate-risk WT. Survival of patients with stage IV DA-WT has not improved compared to the previous SIOP93-01 study. Conclusion These results call for new treatment approaches for patients with HR stage IV WT.

The impact of biopsying Wilms tumour (WT) at diagnosis on assigning the tumour stage and recommended treatment remains controversial. To address this important question, we analysed the potential association of all types of biopsy with local recurrence in patients treated in the SIOP WT 2001 trial, where needle biopsy was permitted without 'upstaging' the tumour to stage III. Only open biopsy required treatment as stage III.Among 2971 patients with unilateral WT (stages I-IV), 420 relapsed (139 local). Risk factors for recurrence were analysed by Cox proportional hazard methods.Biopsy was performed in 969 of 2971 (33%) patients (64% cutting needle, 30% fine needle aspiration [FNA] and 6% open biopsy). Biopsied patients were older, with larger tumours and a greater proportion with high-risk histology. In multivariate analysis that included all factors associated with local recurrence in univariate analysis, only high-risk histology (hazard ratio [HR] = 2.32; 95% confidence interval [CI]: 1.58-3.42, p=0.0001), age≥2 years (HR = 2.24; 95% CI: 1.22-4.09, p = 0.01) and preoperative tumour volume (HR = 1.07 per 100 ml; 95% CI: 1.02-1.12, p = 0.01) were significant. The HR for the association of local recurrence and event-free and overall survival with biopsy was not significant (HR = 1.4; 95% CI: 0.9-2.17, p = 0.13; HR = 1.1; 95% CI: 0.85-1.42, p = 0.46 and HR = 1.13; 95% CI: 0.79-1.62, p = 0.51, respectively). These results were not materially different whether FNA or open biopsy were included in the biopsy group or not.This post hoc analysis provides some reassurance that needle biopsy is not an independent adverse factor for either local recurrence or survival after adjustment for all relevant risk factors. Needle biopsy should not be an automatic criterion to 'upstage' WT.

The >90% rates of overall survival for children with Wilms tumour are remarkable and have been achieved at the same time as reducing treatment for most patients. However, beneath this headline figure, 20% of patients still relapse after first-line therapy and up to 25% of survivors report severe late effects. The aim of the SIOP-RTSG is to improve outcomes and to reduce acute and late treatment toxic effects in all children

Congenital mesoblastic nephroma (CMN) is a rare pediatric renal tumor with low malignant potential that most commonly occurs early in infancy. Treatment strategies are based on the few published CMN series, while a significant number of CMN patients have been described in case reports. The aim of this narrative review was to create an up-to-date overview of the literature. Complete surgical removal is curative in most cases. The risk of treatment-related mortality (both surgery- and chemotherapy-related) is relatively high in the first weeks of life, indicating that these young patients deserve special attention with respect to timing and type of treatment.

BACKGROUND The risk factors responsible for recurrences of Wilms' tumor (nephroblastoma) are still under discussion. The aim of the study was to analyze the relationship between relapses of Wilms' tumor and the patients' clinical history. MATERIAL AND METHODS Clinical data from children registered in the Polish Pediatric Solid Tumors Study Group were analyzed. The clinical stages (CS), pathology variants (high risk: HR, intermediate risk: INT, and low risk: LOW) and chemotherapy regimens were correlated with the outcomes. RESULTS Recurrences developed in 34 out of 288 (11.8%) patients with Wilms' tumor treated in accordance with International Society for Pediatric Oncology 2001 (SIOP 2001) protocols. Of these 34 patients, 11 initially had CS I, seven were at CS II, four were at CS III, 11 were at CS IV and one had CS V. There were eight patients with second recurrences; of these, seven were in the INT risk group and one in the high histological risk group. There was no correlation between age (p=0.256) or gender (p=0.538) and the risk of tumor recurrence. In the study group, seven out of 10 patients with local recurrences are alive; as are 13 out of 22 patients with distant recurrences (p=0.703). Those who died due to disease progression comprised six out of 26 patients with a first recurrence (four HR, two INT), and seven out of eight with a second recurrence (one HR, six INT). CONCLUSIONS The prognosis after relapse in initially metastatic patients did not differ from that in patients who had primarily localized disease. The pathology variants probably had more significance.

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. (C) 2014 Elsevier Ltd. All rights reserved

Objective To analyse ovarian Sertoli-Leydig cell tumours (SLCTs) for potential prognostic markers and their use for treatment stratification. Patients Forty-four patients were included. Patients were prospectively reported to the German MAKEI (Maligne Keimzelltumoren) studies ( n =23), French TGM protocols ( n =10), Italian Rare Tumour Project (TREP) registry ( n =6), and the Polish Pediatric Rare Tumour Study group ( n =5). Tumours were classified according to World Health Organisation (WHO) and staged according to International Federation of Gynecological Oncology (FIGO). Results Median age was 13.9 (0.5–17.4) years. All patients underwent resection by tumour enucleation ( n =8), ovariectomy ( n =17), adenectomy isolated ( n =18) or with hysterectomy ( n =1). FIGO-stage: Ia 24pts., Ic 17pts., II/III 3pts. One patient had bilateral tumours. Four patients (stage Ia: 3, stage Ic: 1) developed a metachronous contralateral tumour. Otherwise, all stage Ia patients remained in complete remission. Among 20 patients with incomplete resection or tumour spread (stage Ic–III), eight relapsed, and five patients died. Eleven patients were initially treated with two to sixcycles of cisplatin-based chemotherapy. Of these, seven patients are in continuous remission. Poor histological differentiation was associated with higher relapse rate (5/13) compared to intermediate (3/18) and high differentiation (0/4). Tumours with retiform pattern or heterologous elements showed a high relapse rate, too (5/11). After a median follow-up of 62months, event-free survival is 0.70±0.07, relapse-free survival 0.81±0.06 and overall survival 0.87±0.05. Conclusions Prognosis of SLCTs is determined by stage and histopathologic differentiation. Complete resection with careful avoidance of spillage is a prerequisite of cure. The impact of chemotherapy in incompletely resected and advanced stage tumours remains to be evaluated.

PURPOSE: To determine the optimal duration of preoperative chemotherapy to further increase the proportion of stage I tumors by comparison of two regimens in the treatment of patients older than 6 months who have unilateral Wilms’ tumor. PATIENTS AND METHODS: Eligible patients (n = 382) initially received four weekly doses of vincristine (VCR) and two courses of actinomycin D (AMD) and were randomized either to be operated on (4-week group [n = 193]) or to receive 4 more weeks of the same chemotherapy regimen (8-week group [n = 189]). The assessment criterion was the observed percentage of stage I tumors. After surgery, patients were assigned according to tumor stage and histology to four different treatment groups: stage I and favorable histology (n = 5) were to have no further treatment (NFT); stage I and standard histology or anaplasia (n = 244), VCR and AMD for 17 weeks (AV); stages II and III and favorable or standard histology, VCR, AMD, and an anthracycline for 27 weeks (AVE) with no abdominal radiotherapy for stage II N0 disease (n = 75) or with a 15-Gy dose of abdominal irradiation (RTH) in case of stages IIN1 and III (n = 56). Anaplastic tumors staged higher than I or clear-cell sarcoma of the kidney (14), AMD, VCR, an anthracycline, and ifosfamide for 36 weeks (DEVI). RESULTS: No advantage was found in favor of prolonged preoperative treatment. The percentages obtained for the 4-week and the 8-week groups, respectively, were as follows: stage I, 64% versus 62%; intraoperative tumor rupture rate, 1% versus 3%; 2-year EFS, 84% versus 83%; and 5-year OS, 92% versus 87%. Two-year EFS and 5-year OS rates, respectively, of the different treatment groups were as follows: NFT, 100% for both EFS and OS; AV, 88% and 93%; AVE, 84% and 88%; AVE RTH, 71% and 85%; and DEVI, 71% and 71%. The rate of abdominal recurrences in stage II N0 nonirradiated patients was 6.6%. CONCLUSION: The 4-week schedule pre-nephrectomy chemotherapy regimen should be considered the standard treatment. Clinical trials should continue to improve the cure rate of high-risk patients and the quality of life of children with a more favorable prognosis.

The aim of the study was to assess rates and types of nephrectomy-related complications in children nephrectomized for nephroblastoma after preoperative chemotherapy. Records of 598 Wilms' tumour patients registered in the International Society of Paediatric Oncology Trial & Study No. 9 (SIOP-9), and pretreated correctly according to the protocol with vincristine + actinomycin D ± epirubicine or adriamycin prior to nephrectomy, were retrospectively reviewed. Forty-nine patients (8%), who suffered from 54 complications, were identified. Most frequent events were small-bowel occlusions (3.7 %) and tumour ruptures (2.8 %). Other complications were registered in 2.0 % of cases. The low rate of nephrectomy complications and no deaths related to registered ones, are another argument for preoperative chemotherapy in Wilms' tumour patients.

The favourable results from the treatment of Wilms' tumour are an example of the success of multimodal therapy in paediatric oncology. The epidemiology, methods of diagnosis, benefits of pre-operative chemotherapy, basic principles of surgery and post-operative treatment modalities are presented. The approach to the management of Wilms' tumour considered in this paper is mainly that of the International Society of Paediatric Oncology.

The low incidence and the heterogeneity of very rare tumors (VRTs) demand for international cooperation. In 2008, EXPeRT (European Cooperative Study Group for Pediatric Rare Tumors) was founded by national groups from Italy, France, United Kingdom, Poland and Germany. The first aims of EXPeRT were to agree on a uniform definition of VRTs and to develop the currently most relevant scientific questions. Current initiatives include international data exchange, retrospective and prospective studies of specific entities, and the development of harmonized and internationally recognized guidelines. Moreover, EXPeRT established a network for expert consultation to assist in clinical decision in VRTs.

Thymoma and thymic carcinoma are infrequent ­epithelial tumors occurring usually in older adults in fourth to sixth life decade, constituting only 0.2–1.5% of all malignancies (Voitz et al. 1997). The classification system, risk factors and treatments have been developed in adults and have been transferred to the treatment of children and adolescents. Pediatric experience, however limited, confirms that characteristics of this disease probably do not change with age. In children, thymomas and thymic carcinomas contribute less than 1% to all mediastinal tumors (Ramon and Suster 1991). Larger multi-center pediatric studies are necessary to definitely confirm this statement (Stachowicz-Stencel et al. 2010; Yaris et al. 2006). Despite low incidence in childhood, it is important to keep in mind this rare condition. On one hand, 30–50% of cases are asymptomatic and recognized incidentally at X-ray performed for other reasons, such as respiratory infection. On the other hand, 30–65% of patients suffer from autoimmune paraneoplastic syndromes related to thymoma. Among these, myasthenia gravis is observed most commonly (Schmidt-Wolf et al. 2003).

Head and neck pathologies are frequent in childhood but rarely have malignant origin. Traumatic lesions, inflammatory enlargement of the lymph nodes, congenital malformations, cysts, hemangioma, lymphangioma, vascular malformations, and even infectious diseases may mimic malignant conditions. A classical diagnostic workup is well applicable to differentiate between those conditions.

Summary Background Present treatment for Wilms' tumour is very successful. Now, efforts are aimed at reducing toxicity and burden of treatment by shortening schedules without loss of effectiveness. The objective of this randomised trial was to assess whether postoperative chemotherapy for patients with stage I intermediate-risk and anaplastic Wilms' tumour could be shortened to only 4 weeks from the standard 18 weeks, while maintaining equivalent event-free survival. Methods Between June, 1993, and June, 2000, 410 patients were randomly assigned after four doses of vincristine plus one course of dactinomycin postoperatively either to stop further adjuvant chemotherapy (no further chemotherapy group, n=200), or to receive a further two courses of the same chemotherapy (standard group, n=210). Previous treatment consisted of chemotherapy before nephrectomy of four doses of vincristine and two courses of dactinomycin followed by surgical resection of the tumour. Eligible patients were at least 6 months old and had stage I tumours with either intermediate-risk histology or anaplasia. The primary endpoint of this equivalence trial was 2-year event-free survival. Both per-protocol and intention-to-treat analyses were done. Findings By 2 years, 18 recurrences were reported in the standard group, and 22 in the no further chemotherapy group. Event-free survival was 91·4% (95% CI 87·5–95·2) for the no further chemotherapy group and 88·8% (84·3–93·2) for the standard group (difference=2·6%, upper 97·5% confidence limit 8·4%). The null hypothesis, that experimental treatment is less effective than standard treatment, could be rejected (p=0·008). Conclusions Shortening duration of chemotherapy could reduce acute and late side-effects and inconvenience for patient and parents while maintaining effectiveness, and could be beneficial in terms of health costs.

Les essais et etudes menes par la Societe Internationale d'Oncologie Pediatrique (SIOP), sur le traitement de la tumeur de Wilms, ont montre que la chimiotherapie pre-operatoire permet d'observer une distribution plus favorable des stades, de diminuer la frequence des complications peri-operatoire et de reduire les traitements post-operatoires, Cependant, certaines situations peuvent conduire a pratiquer rapidement une chirurgie premiere. Cette etude a pour but d'evaluer les indications d'une nephrectomie premiere en urgence. Sept cent vingt cas de nephroblastome unilateraux et non-metastatiques enregistres dans l'essai et l'etude SIOP 9 ont ete revus. Vingt-quatre (3%) cas operes d'emblee en urgence ont ete identifies parmi eux. Une chirurgie premiere a ete motivee par une hemorragie massive liee a une rupture tumorale pour 13 patients, une suspicion d'abdomen aigue pour 7 patients, une occlusion intestinale pour 2, et pour d'autres raisons. Au cours du traitement post-operatoire 72% de ces patients ont ete irradies et 92% ont recu des anthracyclines. Des complications peri-operatoire sont survenues frequemment: 25% des cas. Cependant, l'evolution a ete favorable et 22 sur 24 sont vivants (recul 7 a 79 mois). Le nombre de patients (7) ayant presente un «abdomen aigue» aurait probablement pu etre largement limite par des procedures d'observation et de diagnostic adaptees.

The surgical treatment of malignant renal tumours in children (nephroblastomas) is part of a multimodal therapeutic strategy, defined by the International Society of Paediatric Oncology protocol. Resection of the primary tumour and determination of the post-operative stage determine subsequent treatment. The modalities of the surgical procedure are described together with the particular cases concerning infants under the age of 6 months, extension to the renal vein and inferior vena cava, emergency surgery, bilateral, tumours or tumour in a solitary kidney, lymph node involvement, metastatic nephroblastomas and complications of surgery.

Treatment of Wilms' tumor is an example of success of modern oncology. A combination of surgery, radiotherapy, and chemotherapy is widely accepted as the efficacious treatment of nephroblastoma. However, timing of each part of the treatment differs, in various protocols: the Societe Internationale d'Oncologie Pediatrique (SIOP) recommends the diagnosis based on imaging and metabolic exclusion of neuroblastoma to reduce the biopsy-related risk of spillage. In patients more than 6 months old, the treatment starts with the preoperative chemotherapy to improve the stage distribution at surgery and decrease the complications rate. Patients with advanced nephroblastoma, as those with vena cava thrombus and lung metastases, can benefit the most from the pretreatment. Results from the SIOP studies 6 and 9 confirm these statements: the stage distribution after the pretreatment reveals more than 50% of cases staged I, the 4-year disease-free survival in pulmonary stages IV was 83%, and of 42 patients with vena cava thrombus still present at surgery, 38 are alive from 27 to 109 months.

The aim of the study was to assess rates and types of nephrectomy-related complications in children nephrectomized for nephroblastoma after preoperative chemotherapy. Records of 598 Wilms' tumour patients registered in the International Society of Paediatric Oncology TrialStudy No. 9 (SIOP-9), and pretreated correctly according to the protocol with vincristine + actinomycin D +/- epirubicine or adriamycin prior to nephrectomy, were retrospectively reviewed. Forty-nine patients (8%), who suffered from 54 complications, were identified. Most frequent events were small-bowel occlusions (3.7%) and tumour ruptures (2.8%). Other complications were registered in 2.0% of cases. The low rate of nephrectomy complications and no deaths related to registered ones, are another argument for preoperative chemotherapy in Wilms' tumour patients.

The favourable results from the treatment of Wilms' tumour are an example of the success of multimodal therapy in paediatric oncology. The epidemiology, methods of diagnosis, benefits of pre-operative chemotherapy, basic principles of surgery and post-operative treatment modalities are presented. The approach to the management of Wilms' tumour considered in this paper is mainly that of the International Society of Paediatric Oncology.

Adrenocortical tumours (ACTs) are rare during childhood. A complete surgical resection provides the best chance of cure, but the role and efficacy of the adjuvant therapy are still controversial. Various histologic criteria of malignancy for ACTs adopted in children do not facilitate comparative studies and are not completely shared. Therefore, a sharp demarcation between benign and malignant lesions has not been recognised, making it difficult to identify who potentially needs perioperative therapy. This manuscript presents the internationally harmonised recommendations for the diagnosis and treatment of ACTs in children and adolescents, established by the European Cooperative Study Group for Paediatric Rare Tumours (EXPeRT) group within the EU-funded project PARTNER (Paediatric Rare Tumours Network - European Registry).