title: Stromal and epithelial predominant Wilms tumours have an excellent outcome: the SIOP 93 01 experience.
abstract: BACKGROUND
  Wilms tumour (WT) has various subtypes that are correlated with prognosis and require distinct therapy. Stromal predominant (SpWT) and epithelial WT (EpWT) have previously been associated with a good outcome. The current analysis describes the outcome and (tumour) characteristics of all patients with SpWT, EpWT, including highly differentiated epithelial type (HDET), treated according to the International Society of Pediatric Oncology (SIOP) 93-01 study.
  
  
  METHODS
  All children older than 6 months and below 18 years of age with localized or metastatic WT and intermediate risk (IR) histology or HDET treated with pre-operative chemotherapy were included in the present analysis.
  
  
  RESULTS
  A total of 1,389 eligible patients had IR or HDET histology: 1% HDET, 4% EpWT, 10% SpWT, and 85% other IR. For EpWT/HDET, 93% had stage I/IIN-, 5-year EFS was 90.2% and overall survival of (OS) 98.4%, as compared to 84.0% and 92.5% in other IR histology (NS). Stage I EpWT/HDET had a significant better outcome than stage I of other IR. In SpWT 82% of cases had stage I/IIN-; 5-year EFS was 94.3% and OS 99.2%, significantly better compared to other IR histology. All patients with stage I are alive (2/149 relapses); 3/52 stage IIN-, 2/21 stage IIN+/III, and 6/12 stage IV patients relapsed (1 deceased per stage group).
  
  
  CONCLUSIONS
  The good outcome for EpWT and SpWT generally is very good which may be related to low age and low stage in most cases. A reduction of treatment intensity and/or duration may be justified especially for low stage SpWT that has an EFS close to 100%.
authors.affiliation: Department of Paediatric Oncology, Academic Medical Centre, University of Amsterdam, Emma Children's Hospital AMC, Amsterdam, The Netherlands. arnauld.verschuur@mail.ap-hm.fr
authors.forename: Arnauld C
authors.initials: AC
authors.lastname: Verschuur
authors.forename: Gordan M
authors.initials: GM
authors.lastname: Vujanic
authors.forename: Harm
authors.initials: H
authors.lastname: Van Tinteren
authors.forename: Kathy Pritchard
authors.initials: KP
authors.lastname: Jones
authors.forename: Jan
authors.initials: J
authors.lastname: de Kraker
authors.forename: Bengt
authors.initials: B
authors.lastname: Sandstedt
mesh_terms: D000971:Antineoplastic Combined Chemotherapy Protocols / Q000008:administration & dosage; D002648:Child; D002675:Child, Preschool; D004847:Epithelial Cells / Q000473:pathology*; D005260:Female; D006801:Humans; D007223:Infant; D007680:Kidney Neoplasms; D008297:Male; D009367:Neoplasm Staging; D009392:Nephrectomy; D011379:Prognosis; D017154:Stromal Cells / Q000473:pathology*; D016019:Survival Analysis; D016896:Treatment Outcome; D009396:Wilms Tumor / Q000401:mortality / Q000473:pathology* / Q000628:therapy