title: Clinical characteristics and outcome of Wilms tumors with a favorable histology in Japan: a report from the Study Group for Pediatric Solid Malignant Tumors in the Kyushu Area, Japan.
abstract: OBJECTIVE
  Since 1996, the standard treatment of Wilms tumors in Japan has been based on the regimen of the Japanese Wilms Tumor Study. However, in Japan, there have been no reports about Wilms tumors that analyzed the clinical features and patient outcome in a large series until now. This study aims to assess the clinical characteristics of patients with Wilms tumor with a favorable histology from a retrospective standpoint in the Kyushu area in Japan and, furthermore, to analyze the historical changes of clinical features and outcome from the 1980s to the 1990s.
  
  
  METHODS
  Between 1982 and 1996, 90 cases of Wilms tumors with a favorable histology were registered in the Kyushu area. Regarding the clinical feature and outcome, they were divided into 2 groups (group A, 1982-1989, n = 50; group B, 1990-1996, n = 40). The outcome was analyzed based on the 5-year overall survival rate.
  
  
  RESULTS
  The clinical features (age, sex, initial symptom, location, stage) demonstrated no definite differences between group A and group B. Regarding the operation, the rate of an initial complete resection in the early stages was significantly higher in group B than in group A. All stage V cases in group B undewent a bilateral tumor biopsy instead of a radical nephrectomy as the initial operation. The 5-year overall survival rate throughout the whole period was 87.8%, whereas the rates were 84.0% for group A and 90.0% for group B (P = NS), respectively. Of particular note, the outcome of patients with stage I and stage V in group B substantially improved in comparison to that in group A. However, in advanced cases, no significant improvement in the outcome was noted.
  
  
  CONCLUSIONS
  This is the first report about the clinical features and outcome for Wilms tumors with a favorable histology in Japan from the 1980s to the 1990s. The present study suggested that in the early-stage cases, an initially complete resection followed by standard postoperative chemotherapy substantially improved the outcome of the patients in group B. In the stage V cases, the performance of renal salvage surgery may have positively contributed to the improvement in the outcome in group B. However, in the advanced stage cases, no definite improvement was noted. In the future, an improved efficacy of the treatments for Wilms tumors based on the standard protocol established by the Japanese Wilms Tumor Study in 1996 is expected in Japan.
authors.affiliation: Department of Pediatric Surgery, Kyushu University, Kyushu University, Higashi-ku, Fukuoka 812-8582, Japan. suita@pedsurg.med.kyushu-u.ac.jp
authors.forename: Sachiyo
authors.initials: S
authors.lastname: Suita
authors.forename: Yoshiaki
authors.initials: Y
authors.lastname: Kinoshita
authors.forename: Tatsuro
authors.initials: T
authors.lastname: Tajiri
authors.forename: Toshiro
authors.initials: T
authors.lastname: Hara
authors.forename: Masazumi
authors.initials: M
authors.lastname: Tsuneyoshi
authors.forename: Hiroyoshi
authors.initials: H
authors.lastname: Mizote
authors.forename: Hiroko
authors.initials: H
authors.lastname: Inada
authors.forename: Hideo
authors.initials: H
authors.lastname: Takamatsu
authors.forename: Yoshifumi
authors.initials: Y
authors.lastname: Kawano
authors.forename: Yukihiro
authors.initials: Y
authors.lastname: Inomata
authors.forename: Akira
authors.initials: A
authors.lastname: Nagasaki
authors.forename: Yasuharu
authors.initials: Y
authors.lastname: Ono
authors.forename: Noritoshi
authors.initials: N
authors.lastname: Handa
authors.forename: Jun
authors.initials: J
authors.lastname: Okamura
authors.forename: Eiichi
authors.initials: E
authors.lastname: Ishii
authors.forename: Kiyoshi
authors.initials: K
authors.lastname: Kawakami
mesh_terms: D002675:Child, Preschool; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007564:Japan; D007680:Kidney Neoplasms / Q000401:mortality* / Q000473:pathology / Q000601:surgery; D008297:Male; D009367:Neoplasm Staging; D009392:Nephrectomy; D012189:Retrospective Studies; D016019:Survival Analysis; D016896:Treatment Outcome; D009396:Wilms Tumor / Q000401:mortality* / Q000473:pathology / Q000601:surgery