[Treatment of childhood cancer in Africa. Action of the Franco-African childhood cancer group]. / Le traitement des cancers de l'enfant en Afrique. Travaux du groupe franco-africain d'oncologie pédiatrique.

The childhood cancer survival rate is currently 75% in industrialized countries. Rates in developing countries are much lower. The Franco-African Childhood Cancer Group (French acronym, GFAOP) was founded in 2000 with aim of reducing this unfavorable situation in Africa. The GFAOP has developed two forms of action. The main form consists of organizing two- to twelve-month training sessions for physicians and nurses in France and Morocco. The other form involves assessing the feasibility of modern treatment protocols for various cancers in Africa. The first feasibility trials were carried out on nephroblastoma and Burkitt's lymphoma in 12 pilot units in North Africa, West Africa, and Madagascar. In the first study from 2001 to 2005 we treated 306 cases of Burkitt's lymphoma using French LMB protocols adapted to the African setting and achieved a survival rate of 61%. A second study started in 2005 using Endoxan alone achieved a highly satisfactory survival rate of 73% for neuroblastoma in all stages except bilateral. Altogether from 2001 to 2007 more than 1000 cases of nephroblastoma and Burkitt's lymphoma were treated in African hospitals by African doctors and nurses. No patients were transferred to Europe. The GFAOP supplied drugs when necessary and took care of most travel expenses. African and French doctors worked together on protocol design, trial management, and data analysis. These promising results show that the latest therapeutic techniques can be used to treat childhood cancer in Africa by adapting the protocol to conditions in developing countries. Sanofi-Aventis Laboratories in association with the International Union against Cancer has launched a major campaign to improve Pediatric Oncology in developing countries. Projects in four GFAOP units are being financed through this campaign. In 2006 the GFAOP began assessment of two new treatment protocols, i.e., one for acute lymphoblastic leukemia and the other for Hodgkin's disease. Two other projects are being planned, i.e., one for treatment of retinoblastoma and the other for treatment of some types of brain tumors.

Wilm's tumor with pulmonary metastases at diagnosis: the significance of primary chemotherapy. International Society of Pediatric Oncology Nephroblastoma Trial and Study Committee.

Data from patients with pulmonary metastases (PM) from Wilms' tumor at diagnosis (stage IV) were collected from six European centers. All patients were pretreated with a chemotherapy (CT) regimen consisting of vincristine (VCR), dactinomycin (AD), and Adriamycin (doxorubicin; Adria Laboratories, Columbus, OH). After nephrectomy, local therapy for residual pulmonary disease was considered to avoid whole-lung irradiation. Only four of 36 patients still had multiple inoperable metastases after preoperative CT. Thirty patients survived. Four of them were irradiated. Of the six patients who died, four died of PM, one died of abdominal recurrence, and one of therapy-related disease. Disease-free survival and actuarial survival rates are 83% with a mean follow-up of 4 years postnephrectomy.

Etoposide in relapsed or refractory Wilms' tumor: a phase II study by the French Society of Pediatric Oncology and the United Kingdom Children's Cancer Study Group.

PURPOSE: Despite a high cure rate of approximately 85% in Wilms' tumor by multimodality therapy, to date only four drugs are known to be active against such tumors. There is a clear need for new active drugs. PATIENTS AND METHODS: Thirty-one patients with relapsed or refractory Wilms' tumor from three British and 14 French centers were treated with intravenous (IV) etoposide 200 mg/m2 daily for 5 days. Original stage was I (n = 3), II (n = 7), III (n = 9), IV (n = 10), and V (n = 2). Prior chemotherapy, administered initially or at relapse, included vincristine and dactinomycin in all cases, doxorubicin or epirubicin in 30, and ifosfamide in 20. Sites of relapse or resistant disease were lung in 13, abdomen or pelvis in six, liver in one, and multiple in 11. When entered onto the study, 12 patients were in first relapse, 10 in second relapse, and four in third or more relapse. Five had never obtained a complete remission. All but two (progressing) patients received two courses of etoposide, the second course being administered at day 21. RESULTS: A complete response (CR) was documented in two patients, partial response (PR) in 11, stable disease in 10, and progressive disease (PD) in eight. The duration of response could not be evaluated, because all responding patients were subsequently treated with multimodality therapy. The major toxicities observed were neutropenia and thrombocytopenia, but most patients had been heavily pretreated. No toxic death clearly associated with etoposide was noted. CONCLUSION: It is concluded that etoposide in this schedule is an active agent in Wilms' tumor and should be considered for inclusion in regimens for high-risk patients, such as those with metastatic disease at diagnosis and those who relapse after multiagent chemotherapy.

Results of the Sixth International Society of Pediatric Oncology Wilms' Tumor Trial and Study: a risk-adapted therapeutic approach in Wilms' tumor.

PURPOSE: The Sixth International Society of Pediatric Oncology study (SIOP6) concerned Wilms' tumor with favorable histology, preoperatively treated to obtain a high rate of stage I patients, and sought to reduce treatment for patients with stage I and stage II negative nodes (IIN0) tumors and to find better therapy to prevent relapses in stage II positive nodes (IIN1) and stage III patients. PATIENTS AND METHODS: Eligible patients (N = 509) had received four weekly doses of vincristine (VCR) and two courses of dactinomycin (AMD) preoperatively and were assigned after surgery, according to stage and lymph node involvement, to three different prognostic groups, which were to be randomized. Stage I patients (n = 303) received VCR and AMD either for 17 weeks (S) or 38 weeks (L). Stage IIN0 patients (n = 123) received either 20 Gy irradiation (R+) or no irradiation (R-) and received VCR and AMD for 38 weeks. Stage IIN1 and III patients (n = 83) received intensified VCR and AMD (INTVCR) versus VCR, AMD, and Adriamycin (ADRIA; Doxorubicin Farmitalia Carbo Erba, Rueil, Malmaison, France; doxorubicin). Assessment criteria were 2-year disease-free survival (DFS) and 5-year survival (SURV) percentages. A stopping rule was added that took into account abdominal recurrences for the stage IIN0 trial. RESULT: A 52% rate of stage I tumors was obtained, with a low rate of ruptures (7%). The 2-year DFS and 5-year SURV rates according to the different therapeutic groups were stage I, 92% versus 88% (equivalent) and 95% versus 92% for S and L, respectively; stage IIN0, 72% versus 78% (stage equivalent) and 88% versus 85% for R+ and R-, respectively; and stage IIN1 and stage III, 49% versus 74% (P < .029) and 77% versus 80% for INTVCR and ADRIA, respectively, which results in an 82% DFS and 89% SURV rate for the entire trial population. However, six abdominal metastases observed during the first year of follow-up (FU) in the R- group versus none in the R+ group resulted in discontinuation of the stage IIN0 trial. CONCLUSION: Risk-adapted therapy to limit risk of sequelae is possible. More intensive chemotherapy is necessary to prevent abdominal recurrences in nonirradiated stage IIN0 patients treated preoperatively. A three-drug protocol is necessary in stage IIN1 and stage III patients.

Bilateral Wilms' tumor: long-term survival and some epidemiological features.

Sixty-seven children with a bilateral Wilms' tumor (BWT) who were registered to the International Society of Pediatric Oncology (SIOP) nephroblastoma trial and studies 1, 2, and 5, conducted between 1971 and 1980, were analyzed. The overall 10-year survival was 64%. While most deaths due to tumor occurred within 3 years after diagnosis of bilateral disease, five patients died after 3 years (20%), three with synchronous and two with metachronous BWT. The survival rates for the 42 children with synchronous BWT (follow-up time, 6 1/2 to 14 years) and the 25 children with metachronous BWT (follow-up time, 5 to 13 years) were 69% and 56%, respectively. Due to an improvement in the synchronous group, overall survival improved over the years: 47%, 72%, and 70%, in SIOP 1, 2, and 5, respectively. Age at diagnosis and most advanced tumor stage affected prognosis. Children presenting a tumor manifestation before the age of 2 years had better prognosis than older children. This difference is significant in synchronous BWT. Prognosis for children with local stage 1 or 2 was better than for those with local stage 3. Median age at initial presentation in BWT was lower than in unilateral nephroblastoma and lower in metachronous BWT than in synchronous BWT. Young children presenting with unilateral nephroblastoma should have a careful follow-up of the contralateral kidney for at least the next 3 1/2 years, as most contralateral tumors will develop during this period.

Ifosfamide is an active drug in Wilms' tumor: a phase II study conducted by the French Society of Pediatric Oncology.

Twenty-one patients with advanced Wilms' tumor entered a phase II study with high-dose ifosfamide (3 g/m2 over two days every 15 days). Mesna and hyperhydration were associated with minimal bladder toxicity. After two courses, five partial responses and six complete responses were observed. Ten patients did not respond. The median duration of response was 2 months (range, 1 to 7). Therapy was delayed because of leukopenia for 1 or 2 weeks in only three cases. Fever and infection were not observed. Seven patients presented with hematuria, three of whom were among the 17 patients coadministered mesna, which did not interfere with subsequent therapy.

Effectiveness of preoperative chemotherapy in Wilms' tumor: results of an International Society of Paediatric Oncology (SIOP) clinical trial.

The results of a controlled clinical trial of preoperative radiotherapy compared to chemotherapy in patients with nephroblastoma are presented. Of 397 histologically proven cases of Wilms' tumor registered at 34 centers between January 1977 and July 1979, 164 were eligible for the trial and were randomized to receive preoperative radiotherapy and chemotherapy (group R, 76 patients) or preoperative chemotherapy (group C, 88 patients). The results were evaluated in terms of the number of surgical tumor ruptures and of local tumor extent at pathologic examination, reflecting the effectiveness of the preoperative treatment. Survival and recurrence-free survival in the two treatment groups were also taken into account. The stage distribution was comparable in the two groups, with 52% stage I tumors in group R, and 43% in group C. Significant changes in the pathologic pattern were more frequent in group R than in group C (53% versus 17%). From these data it is concluded that preoperative chemotherapy is as good as preoperative radiotherapy in terms of prevention of tumor rupture. In addition, it was shown that 43% of an unselected population of patients with Wilms' tumor could be treated without any radiotherapy when chemotherapy had been given preoperatively.

Optimal duration of preoperative therapy in unilateral and nonmetastatic Wilms' tumor in children older than 6 months: results of the Ninth International Society of Pediatric Oncology Wilms' Tumor Trial and Study.

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.

Etoposide and carboplatin: a highly effective combination in relapsed or refractory Wilms' tumor--a phase II study by the French Society of Pediatric Oncology.

PURPOSE: Since we had previously demonstrated encouraging efficacy of etoposide in patients with relapsed or refractory Wilms' tumor (WT), the likely synergism between etoposide and platinum compounds prompted us to conduct a phase II study of a combination with carboplatin. PATIENTS AND METHODS: Twenty-six relapsed or refractory WT patients were included in a phase II study of two courses of combination etoposide 100 mg/m2/d for 5 days and carboplatin 160 mg/m2/d for 5 days, with a 21-day interval between the two courses. Initial stages were I (n = 2), II (n = 8), III (n = 6), IV (n = 6), V (n = 3), and unknown (n = 1). Sites of diseases were lung(s) (11 patients), abdomen-pelvis or liver or primary tumor (six patients), and multiple (eight patients). Histology was unfavorable in three of 26 patients. RESULTS: Complete response (CR) was documented in eight patients and partial remission (PR) in 11 (overall response rate, 73%). Stable disease (SD) was observed in five patients and progressive disease (PD) in two. Thrombocytopenia (grade IV) was the major toxicity, and platelet transfusions were required in all but two patients. Grade III anemia and grade III to IV neutropenia were seen in 19 and 23, respectively, of 25 assessable first courses. Venoocclusive disease of the liver was fatal in one child who had undergone irradiation to the whole abdomen, 8 weeks before study. CONCLUSION: Combination etoposide and carboplatin has impressive activity in refractory or relapsed WT at the cost of high-grade hematologic toxicity, especially thrombocytopenia. It is of great interest in second-line therapy, since eight of 26 patients are still alive in continuous CR (median follow-up duration, 40 months; range, 24 to 56). This combination deserves further investigation as first-line or consolidation treatment.

High-dose melphalan, etoposide, and carboplatin followed by autologous stem-cell rescue in pediatric high-risk recurrent Wilms' tumor: a French Society of Pediatric Oncology study.

PURPOSE: The three-drug combination of melphalan (M), etoposide (E), and carboplatin (C) followed by autologous stem-cell (ASC) rescue has been evaluated prospectively by the French Society of Pediatric Oncology (SFOP) in pediatric high-risk recurrent (HRR) Wilms' tumor (WT) patients with chemotherapy-responsive disease. PATIENTS AND METHODS: From October 1988 to October 1994, 29 patients with HRR WT were treated in nine SFOP centers. Two additional patients with stage IV anaplastic WT were consolidated in first complete response (CR) with the same regimen and have been studied separately. The regimen consisted of M 180 mg/m2 for 1 day, E 200 mg/m2/d for 5 days, and C at a daily targeted area under the concentration-time curve (AUC) of 4 mg x min/mL for 5 days. ASCs were reinfused 48 hours after M. RESULTS: Twelve of 28 assessable patients with HRR WT are still in continuous CR at a median of 48.5 months (range, 36 to 96) after consolidation. Disease-free survival (DFS) and overall survival (OS) estimated by the Kaplan-Meier method at 3 years were 50%+/-17% and 60%+/-18%, respectively. Sixteen patients relapsed at a median of 8.5 months (range, 3 to 53) after consolidation. Toxicity data are available in 31 grafted patients. Grade III and IV toxicities included hematologic side effects (n=31), hemorrhage (n=8), mucositis (n=24), diarrhea (n=12), renal disorders (n=8), and pneumonitis (n=3). CONCLUSION: The adverse prognostic factors (APF) used to select patients for this dose-intensive chemotherapy define children with very-poor-risk recurrent WT. Despite high treatment-related toxicity, about half of these patients remain disease-free at 3 years. Patient outcome is statistically better when high-dose chemotherapy (HDCT) is performed as early as the second CR or partial response (PR). Novel therapeutic approaches with innovative preparative regimens are warranted for the remaining high-risk patients.

Reduction of postoperative chemotherapy in children with stage I intermediate-risk and anaplastic Wilms' tumour (SIOP 93-01 trial): a randomised controlled trial.

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.

WT1 splicing alterations in Wilms' tumors.

Hereditary and sporadic forms of tumors are generally related to germ-line and somatic mutations of the same tumor suppressor gene. Unexpectedly, in Wilms' tumor, somatic mutations of the WT1 gene were found only occasionally in sporadic cases, although constitutional mutations of this gene are clearly associated with predisposition. It has been suggested that abnormal splicing may be another mode of somatic WT1 alteration. However, this idea was based on the analysis of a small series of tumors, precluding accurate evaluation of the frequency of such changes. To investigate WT1 changes at the somatic level in more detail, we analyzed the levels of the four isoform transcripts produced by alternative splicing events in a large series of 50 tumors, normal mature kidneys, and fetal kidneys. We characterized splicing alterations in 63% of sporadic Wilms' tumors. Moreover, taking into account the decreased and increased overall levels of WT1 mRNA, the percentage of sporadic tumors with changes in WT1 expression reached 90%. Whether and how these alterations of expression play a role in the tumorigenic process remain to be evaluated.

Testing genomic imprinting in Wilm's tumor.

Data from 511 cases of Wilms' tumor in France (including 12 familial cases) and 8 pedigrees from the literature were analyzed to test three modifications of Knudson's classical bimutational theory, based on genomic imprinting in Wilms' tumor carcinogenesis. Analysis of data of age at diagnosis and segregation analysis were performed to determine the number of independent events for Wilms' tumor development and to search for a differential role of paternal and maternal alleles. Unexpectedly, we show that only one rare event is required for tumor development in isolated unilateral cases which are considered to be mainly nonhereditary. In familial cases, we observe no effect of the sex of the transmitting parent on either hge at diagnosis or segregation ratio. We show that this could be explained by models of genomic imprinting which assume two nonindependent events, or only one rare genetic event. In bilateral cases we show a bimodality for age at diagnosis which could be due to a mixture of hereditary and nonhereditary cases. This result completely questions the classical assumption according to which all bilateral cases would be hereditary. These findings support the hypothesis that this childhood cancer arises from a variety of etiological pathways and might be useful to find strategies for further molecular investigations.

Somatic mosaicism for partial paternal isodisomy in Wiedemann-Beckwith syndrome: a post-fertilization event.

Genomic imprinting has been implicated in the aetiology of an overgrowth cancer-prone syndrome, the Wiedemann-Beck-with syndrome (WBS). We have demonstrated uniparental disomy (UPD) for paternal chromosome 11p markers in 5 out of 25 sporadic cases (20%). Delineation of the extent of the disomy region may help in understanding the mechanism and the stage, meiotic or mitotic, of disomy formation in this disease and in associated tumours. Our current studies in WBS patients with seventeen 11p and one 11q markers reveal paternal isodisomy, not heterodisomy, in the five cases. For one case we demonstrate unambiguously that partial isodisomy for 11p and somatic mosaicism for UPD resulted from a post-fertilization event. The restriction of isodisomy to part of 11p in another case, and somatic mosaicism for UPD in three other cases, suggest a mitotic recombinational event that must have occurred after fertilization. Mosaic phenotypes reflect the timing of their origin and the fate of the cells involved, as well as the cell-specific pattern of imprinting. Somatic mosaicism for UPD in four cases may thus explain the incomplete forms of WBS. The association of hemihypertrophy in sporadic WBS and even some cases of isolated hemihypertrophy. This is in agreement with a recent report of paternal isodisomy for 11p markers in a patient with hemihypertrophy, Wilms' tumour and adrenocortical carcinoma. Moreover, the risk of developing a tumour seems higher (50%) for patients with paternal 11p UPD than for WBS patients in general (7.5%).

Adult Wilms' tumour: review of 22 cases.

The Institut Gustave Roussy experience with nephroblastoma in 22 patients older than 16 years during a 19-year period (1973-1992) was retrospectively reviewed. All patients underwent a nephrectomy. There were 4 stage I, 8 stage II, 3 stage III and 7 stage IV patients. Initial postnephrectomy therapy included single modality approach in 7 patients (radiotherapy in 1 and chemotherapy in 6) and combined modality approach (radiotherapy and chemotherapy) in 15 patients. The agents used most often were actinomycin, vincristine and doxorubicin. 2 of 7 (29%) and 7/15 (47%) patients are disease-free survivors after first-line treatment. Salvage chemotherapy was given in 13 patients. Only 1 patient experienced a subsequent sustained complete remission. After a mean follow-up of 100 months (range 10-240), 12/22 patients (55%) are alive, including 10 who are disease-free (45%). We confirm that adult patients are likely to have more advanced disease and poorer prognosis than children. The combined modality approach is more active than one-modality therapy. Aggressive treatment, including the three-drug regimen actinomycin+vincristine+doxorubicin, regardless of stage, associated to irradiation starting from stage II, is recommended.

Abdominal recurrences in Wilms' tumours: a report from the SIOP Wilms' tumour trials and studies.

The Wilms' tumour trials and studies conducted from 1971 to 1980 registered 1042 patients. Of these, 82 patients developed an abdominal recurrence. Particulars of these were studied. Half of the recurrences occurred in stage III patients. Often several untoward prognostic factors could be identified, such as large tumour size, difficult operation, incomplete excision, peritoneal adhesions or metastases, tumour extending to renal vein or vena cava. A tumour rupture increases the chance for an abdominal recurrence, especially if appropriate radiotherapy is not given. In many of these cases, postoperative radiotherapy seems to have been insufficiently tailored to the operative findings. For stage III cases, a careful discussion between surgeon, radiotherapist, and pathologist should lead to the optimal radiotherapy field size and dose for each individual patient, so that the risk of abdominal recurrence can be reduced.

A phase II study of ifosfamide in the treatment of relapses in Wilms' tumor.

The purpose of this study was to evaluate the antitumor activity and tolerability of ifosfamide (IFO) at a dose of 3 g/m2, given on 2 consecutive days every 2 weeks, in advanced Wilms' tumor patients in whom conventional therapy had failed. Mesna and hyperhydration were concomitantly given to minimize bladder toxicity. A total of 21 patients with advanced Wilms' tumor were entered in the study. The response observed after two courses was complete in 6 patients and partial in 5; 10 did not respond; the median duration of response was 2 months (range, 1-7 months). Leucopenia caused a delay in therapy for 1 or 2 weeks in only three cases. Neither fever nor infection were observed. Of 7 patients who developed hematuria, 3 were among the 17 who concurrently received mesna. The urotoxicity did not interfere with subsequent therapy in these three cases.

The management of relapsed Wilms tumor.

Relapsed Wilms tumor is often very responsive to re-treatment, and cures are possible in many cases. Recurrent Wilms tumor forms a heterogeneous group because initial therapies vary widely. Given the complexity of the problem, there is a great need for an organized clinical investigative approach. Ideally, the treatment of initial relapse should be specified by the primary treatment protocol in order to better evaluate overall survival as an end-point for new primary therapy strategies. This is especially appropriate for Wilms tumor, because the investigations of this tumor over the last 20 years have attempted to determine the minimal therapy necessary for cure. Thus, survival rather than relapse-free survival is the most appropriate criterion for the success of a primary retreatment regimen. This investigative approach would also allow evaluation of treatment strategies tailored to a specific patient population. Important questions remain for those who treat recurrent Wilms tumor. Defining the role of high-dose therapy, defining the role of total body irradiation in high-dose therapy regimens, and defining the benefit and toxicity of cyclophosphamide compared with ifosfamide are three current questions under investigation. Developing new agents and regimens effective against Wilms tumor, especially against anaplastic tumors, RTK, and CCSK, is extremely important if progress is to be made in treating these tumors after relapse. Finally, there is a strong need to develop biologic information about tumors that recur, so not only will we better understand why patients relapse but also we can develop therapy tailored specifically to the biology of the recurrent tumor.

The role of preoperative chemotherapy in the management of Wilms' tumor. The SIOP studies. International Society of Pediatric Oncology.

More than 25 years after introducing preoperative chemotherapy for Wilms' tumor, the benefits of this approach are well known. The preoperative protocol results in easier operations with significantly fewer tumor ruptures during surgery and a favorable stage distribution. Acute toxicity and late effects are minimized without jeopardizing disease-free and overall survival. Future clinical trials of Wilms' tumor should seek additional risk factors to stratify and individualize treatment. These prognostic factors will improve the cure rates for high-risk patients by intensifying therapy and the quality of life for children with more favorable prognosis by lowering therapy to a minimum. As is true for radical surgery, partial nephrectomy in unilateral disease must be evaluated in carefully selected patients according to clear and well-defined indications. Molecular genetic studies should increase understanding of Wilms' tumor, influencing treatment and outcome.

Paediatric surgical oncology. 5--Nephroblastoma. International Society of Paediatric Oncology (SIOP) Nephroblastoma Trial & Study Committee.

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.