Characteristics and outcome of stage II and III non-anaplastic Wilms' tumour treated according to the SIOP trial and study 93-01.

PURPOSE: To determine the prognosis of children with stage II and III of low or intermediate risk histology (SIOP classification) in unilateral localised Wilms tumour (WT) after neoadjuvant chemotherapy according to the trial and study of the International Society of Paediatric Oncology, SIOP 93-01. PATIENTS AND METHODS: Patients with unilateral localised WT and stage II or III with low (LR) or intermediate risk (IR) histology between 6 months and 18 years of age, were selected from the total sample of patients registered in the SIOP 93-01 study between June 1993 and December 2001. All patients received 4 weeks of actinomycin-D/vincristine before surgery. Postoperative chemotherapy consisted of actinomycin-D, vincristine and epirubicin/doxorubicin for 27 weeks. Flank or whole abdomen irradiation was given for stage III. Event-free survival (EFS) and overall survival (OS) were analysed for various subgroups. RESULTS: Of 1476 registered patients 594 (40%) met the inclusion criteria for this analysis. Four hundred and two (67%) had stage II disease and 563 (95%) had intermediate risk histology. Median tumour volume was 439 ml at diagnosis and 163 ml after preoperative chemotherapy. With a median follow-up of 8 years, 5-year EFS was 90% (95% confidence interval [95% CI]: 87-92%) and OS 95% (95% CI: 93-97%). Patients with stage III, blastemal type histology and a large volume at surgery had a worse outcome. CONCLUSION: Treatment for stage II and III LR or IR WT is successful in a neoadjuvant setting as advised by the SIOP. Stage, tumour volume and blastemal type histology are the most important prognostic factors.