Results of the Childhood Cancer and Leukaemia Group's United Kingdom Relapsed Wilms Tumour Trial

Background: The United Kingdom relapsed Wilms tumour (UKW-R) trial aimed to improve the historically low survival rates after relapse of Wilms tumour (WT) through a prospective national risk-stratified protocol. The trial also evaluated efficacy and toxicity of high-dose melphalan.

Methods: Patients with relapsed/refractory WT were allocated to one of three treatment groups based on time to relapse and initial therapy. Group A: Patients with Stage 1 non-anaplastic WT treated only with vincristine (VCR) or up to two doses of VCR + actinomycin D (ACT) relapsing > 6 months from diagnosis received ‘intensive’ AVD (ACT + VCR + doxorubicin [DOX]). Group B: Patients with Stage 2 non-anaplastic WT treated with VCR + ACT relapsing > 6 months from diagnosis received eight alternating courses of DOX/cyclophosphamide (CPM) and CPM/etoposide (ETOP). Group C: All other patients whose initial therapy included additional DOX, other drugs and/or radiotherapy received six alternating courses of carboplatin (CARBO)/ETOP and CPM/ETOP followed by melphalan + autologous stem cell rescue (M + ASCT). All patients were recommended radiotherapy ± surgery for sites of relapse.

Results: From 2002 to 2008, 78 children were enrolled (Group A: 13, Group B: 10 and Group C: 55). Median age was 5.3 years. 38 children received M + ASCT with no transplant related mortality. 25 children died (5: Group A + B and 20: Group C), all from tumour related causes. The 4-year event-free and overall survival for the whole group were 63% and 68%, and 77%/81% (Group A + B) and 57%/63% (Group C), respectively. Median follow-up for alive patients is 65.4 months (8.1–155.4).

Discussion: Survival rates following risk stratification including M + ASCT are higher than historical observations for similar high-risk groups that did not include high-dose chemotherapy.