Treatment and outcome of Wilms' tumour patients: an analysis of all cases registered in the UKW3 trial

The randomised findings of the UKW3 trial were that preoperative chemotherapy was associated with a more advantageous stage distribution and reduction in therapy burden versus immediate nephrectomy without compromising outcome in localised Wilms' tumour (WT). We analysed outcome in all WT registered in UKW3. Seven hundred and eighteen WT cases (7% anaplastic) were registered in UKW3. We assigned a treatment stage and conducted survival analysis. Five-year event-free survival (EFS) and overall survival (OS) were 77.2% [95% confidence interval (CI) 73.9-80.2] and 87.5% (95% CI 84.8-89.7) after median follow-up of 9.5 years and 10.0 years, respectively. Five-year OS in localised non-anaplastic cases was 92.9% (95% CI 90.2-94.9). Anaplasia was associated with adverse outcome compared with non-anaplastic cases: 5-year EFS of 42.0% (95% CI 28.3-55.1) versus 79.8% (95% CI 76.5-82.7) and 5-year OS of 60% (95% CI 45.1-72.0) versus 89.6% (95% CI 87.0-91.7), respectively. Outcomes were similar for non-anaplastic stage I or II but significantly poorer in stage III cases than stage I. Five-year OS after relapse was 54.1% (95% CI 44.5-62.8). Forty-seven percent of non-anaplastic WT received anthracycline; 27% were treated with radiotherapy first line. These outcomes provide a baseline for future comparisons of WT treatment approach, burden and patient outcome.