Immediate nephrectomy versus preoperative chemotherapy in the management of non-metastatic Wilms' tumour: results of a randomised trial (UKW3) by the UK Children's Cancer Study Group.

PURPOSE: To determine if patients receiving preoperative chemotherapy with vincristine and actinomycin D for non-metastatic Wilms' tumour have a more advantageous stage distribution and so need less treatment compared to patients who have immediate nephrectomy, without adversely affecting outcome. METHODS: Between 1991 and 2001, a total of 205 patients with newly diagnosed non-metastatic renal tumours, of which 186 had Wilms' histologies, were randomly assigned either to immediate surgery or to 6 weeks preoperative chemotherapy and then delayed surgery. Both groups of children received postoperative chemotherapy according to tumour stage and histology determined at the time of nephrectomy. RESULTS: There was a significant improvement in the stage distribution for patients with Wilms' histologies receiving delayed surgery compared to those having immediate nephrectomy (stage I: 65.2% versus 54.3%; stage II: 23.9% versus 14.9%; stage III: 9.8% versus 29.8%, chi2 test for trend=7.02, p=0.008). This improvement resulted in 20% fewer children receiving radiotherapy or doxorubicin yet event-free and overall survivals at 5 years of 79.6% and 89.0%, respectively, were similar in the two groups. CONCLUSION: Six weeks of preoperative chemotherapy with vincristine and actinomycin D results in a significant shift towards a more advantageous stage distribution and hence reduction in therapy, while maintaining excellent event free and overall survival in children with non-metastatic Wilms' tumour. Around 20% of survivors were therefore spared the late-effects of doxorubicin or radiotherapy. Our results suggest that all children with non-metastatic Wilms' tumour should receive chemotherapy prior to tumour resection.