title: Efficacy of Preoperative Chemotherapy in Treatment of Children With Wilms' Tumor: A Meta-Analysis.
abstract: BACKGROUND
  To assess the efficacy of preoperative chemotherapy in Wilms' tumor patients and explore its true value for specific subgroups.
  
  
  OBJECTIVE
  In the presence of these controversies, a meta-analysis that examines the efficacy of preoperative chemotherapy in Wilms' tumor patients and specific subgroups is needed to clarify these issues. The objective of this meta-analysis is to assess the efficacy of preoperative chemotherapy in Wilms' tumor patients and explore its true value for specific subgroups.
  
  
  METHODS
  Computer-based systematic search with "preoperative chemotherapy", "Neoadjuvant Therapy" and "Wilms' tumor" as search terms till January 2013 was performed.
  
  
  METHODS
  No language restrictions were applied. Searches were limited to randomized clinical trials (RCTs) or retrospective studies in human participants under 18 years. A manual examination of references in selected articles was also performed.
  
  
  METHODS
  Relative Risk (RR) and their 95% Confidence Interval (CI) for Tumor Shrinkage (TS), total Tumor Resection (TR), Event-Free Survival (EFS) and details of subgroup analysis were extracted. Meta-analysis was carried out with the help of the software STATA 11.0. Finally, four original Randomized Clinical Trials (RCTs) and 28 retrospective studies with 2375 patients were included.
  
  
  RESULTS
  For preoperative chemotherapy vs. up-front surgery (PC vs. SU) group, the pooled RR was 9.109 for TS (95% CI: 5.109 - 16.241; P < 0.001), 1.291 for TR (95% CI: 1.124 - 1.483; P < 0.001) and 1.101 for EFS (95% CI: 0.980 - 1.238; P = 0.106). For subgroup short course vs. long course (SC vs. LC), the pooled RR was 1.097 for TS (95% CI: 0.784 - 1.563; P = 0.587), 1.197 for TR (95% CI: 0.960 - 1.493; P = 0.110) and 1.006 for EFS (95% CI: 0.910 - 1.250; P = 0.430).
  
  
  CONCLUSIONS
  Short course preoperative chemotherapy is as effective as long course and preoperative chemotherapy only benefits Wilms' tumor patients in tumor shrinkage and resection but not event-free survival.
authors.affiliation: Department of Hepatobiliary and Pancreatic Surgery, Key Laboratory of Combined Multi-Organ Transplantation, School of Medicine, First Affiliated Hospital, Zhejiang University, Hangzhou, China.
authors.forename: Jia
authors.initials: J
authors.lastname: Junjun
authors.affiliation: School of Medicine, Children's Hospital, Zhejiang University, Hangzhou, China.
authors.forename: Zhou
authors.initials: Z
authors.lastname: Xuelian
authors.affiliation: School of Medicine, Zhejiang University, Hangzhou, China.
authors.forename: Kadel
authors.initials: K
authors.lastname: Dhruba
authors.affiliation: Department of Hepatobiliary and Pancreatic Surgery, Key Laboratory of Combined Multi-Organ Transplantation, School of Medicine, First Affiliated Hospital, Zhejiang University, Hangzhou, China.
authors.forename: Xie
authors.initials: X
authors.lastname: Haiyang
authors.affiliation: Department of Hepatobiliary and Pancreatic Surgery, Key Laboratory of Combined Multi-Organ Transplantation, School of Medicine, First Affiliated Hospital, Zhejiang University, Hangzhou, China.
authors.forename: Zhou
authors.initials: Z
authors.lastname: Lin
authors.affiliation: Department of Hepatobiliary and Pancreatic Surgery, Key Laboratory of Combined Multi-Organ Transplantation, School of Medicine, First Affiliated Hospital, Zhejiang University, Hangzhou, China.
authors.forename: Zheng
authors.initials: Z
authors.lastname: Shusen
keywords: Event Free Survival; Meta-Analysis; Wilms’ Tumor