WILMS-TUMOR - OPTIMAL TREATMENT STRATEGIES

Wilms' tumour (WT) is the most common renal tumour in children. Much p rogress has been made in the management of patients with this malignan cy over the last 3 decades. The improved outcome has mainly resulted f rom the availability of cooperative national and international trials involving the National Wilms' Tumour Study Group (NWTS) and the Intern ational Society of Paediatric Oncology (SIOP). These groups have focus ed on optimising postoperative (NWTS) and preoperative (SIOP) therapy, respectively. The early studies by the NWTS (1 and 2) identified the following separate subgroups of patients (based on age and stage) that benefited either from the addition of irradiation to postoperative ch emotherapy or from combination chemotherapy as opposed to single agent s, and those patients who did not benefit from prolonged chemotherapy administration. Additionally, these studies identified histologic feat ures associated with a poor outcome. The more recent studies by NWTS ( 3 and 4) concentrated on reducing treatment for low risk patients to a void long term sequelae while intensifying therapy for patients with h igh risk features, such as those with unfavourable histology and/or me tastatic disease. The early SIOP trials (1, 2 and 5) concluded that pa tients treated with pre operative therapy (chemotherapy alone or combi ned with irradiation) experienced fewer intraoperative tumour ruptures compared with patients who had immediate surgery. However, preoperati ve chemotherapy preserved tumour histology at surgical exploration bet ter than preoperative irradiation. The more recent SIOP trials (6, 9 a nd 93-01) have compared the use of different preoperative treatment re gimens as well as the intensity and duration of postoperative therapy based on prognostic features (stage and histology). These studies have also identified groups benefiting from the addition bf irradiation an d/or the use of a third chemotherapeutic agent. Bilateral WT occurs in a small percentage of patients and treatment strategies, although eff icacious, are limited by the need to maximise residual renal parenchym a. Recurrent WT occurs in 10 to 15% of cases and although a proportion of patients are curable, the overall outcome is poor with 3-year surv ival being in the range of 30%. There are several ongoing studies util ising new drug combinations (carboplatin, cyclophosphamide and etoposi de) attempting to improve the outcome for these patients. Overall, the majority of patients with WT will be cured and become long term survi vors. Cooperative group studies continue to address the issue of minim ising long term morbidity for low risk patients while maximising outco me for high risk patients.