title: Variations in survival and perioperative complications between hospitals based on data from two phase III clinical trials for oesophageal cancer.
abstract: BACKGROUND
  Variations in institutional practice may contribute to different outcomes of cancer treatment. The impact of interinstitutional heterogeneity on outcomes between hospitals after oesophagectomy has not been examined previously using data from surgical clinical trials.
  
  
  METHODS
  The data from two phase III trials for oesophageal cancer were used. Japan Clinical Oncology Group (JCOG) 9204 involved oesophagectomy (92-OP) versus oesophagectomy plus postoperative chemotherapy (92-POST), with accrual from 1992 to 1997. JCOG9907 involved postoperative chemotherapy (99-POST) versus preoperative chemotherapy (99-PRE), with accrual from 2000 to 2006. Hospitals contributing fewer than three patients were excluded. The influence of time and preoperative chemotherapy on interinstitutional heterogeneity related to postoperative complications and 5-year overall survival were evaluated by comparisons within and between these trial groups. Heterogeneity was estimated by a mixed-effects model after adjusting for age, sex, performance status, location of the primary tumour and clinical stage.
  
  
  RESULTS
  Twelve hospitals in 92-OP (114 patients), 13 in 92-POST (114), 19 in 99-POST (158) and 18 in 99-PRE (154) were eligible. There was considerable heterogeneity in predicted postoperative complications in both groups in JCOG9204 (median 31.3 (range 15.0-68.2) per cent), and in 99-PRE (35.2 (22.6-46.6) per cent) but not in 99-POST (27.7 (27.7-27.7) per cent) from JCOG9907. A similar pattern was seen for predicted overall survival (92-POST: 66.4 (range 64.1-68.9) per cent; 99-PRE: 55.9 (54.0-59.7) per cent; 99-POST: 44.4 (44.4-44.4) per cent).
  
  
  CONCLUSIONS
  Interinstitutional heterogeneity regarding complications and survival after oesophagectomy is a problem that merits wider consideration.
authors.affiliation: Japan Clinical Oncology Group (JCOG) Data Centre/Operations Office, Centre for Research Administration and Support, National Cancer Centre, Tokyo, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Kataoka
authors.affiliation: Japan Clinical Oncology Group (JCOG) Data Centre/Operations Office, Centre for Research Administration and Support, National Cancer Centre, Tokyo, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Nakamura
authors.affiliation: Japan Clinical Oncology Group (JCOG) Data Centre/Operations Office, Centre for Research Administration and Support, National Cancer Centre, Tokyo, Japan.
authors.forename: J
authors.initials: J
authors.lastname: Mizusawa
authors.affiliation: Japan Clinical Oncology Group (JCOG) Data Centre/Operations Office, Centre for Research Administration and Support, National Cancer Centre, Tokyo, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Fukuda
authors.affiliation: Oesophageal Surgery Division, National Cancer Centre Hospital, Tokyo, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Igaki
authors.affiliation: Department of Gastrointestinal Surgery, Tokai University School of Medicine, Isehara, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Ozawa
authors.affiliation: Department of Chemotherapy and Palliative Care, Tokyo Women's Medical University, Tokyo, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Hayashi
authors.affiliation: Gastrointestinal Medical Oncology Division, National Cancer Centre Hospital, Tokyo, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Kato
authors.affiliation: Department of Surgery, Keio University School of Medicine, Tokyo, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Kitagawa
authors.affiliation: International Goodwill Hospital, Yokohama, Japan.
authors.forename: N
authors.initials: N
authors.lastname: Ando
mesh_terms: D000328:Adult; D000368:Aged; D000970:Antineoplastic Agents / Q000008:administration & dosage; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use; D018196:Carcinoma, Adenosquamous / Q000188:drug therapy / Q000401:mortality / Q000601:surgery*; D002294:Carcinoma, Squamous Cell / Q000188:drug therapy / Q000401:mortality / Q000601:surgery*; D017024:Chemotherapy, Adjuvant; D002945:Cisplatin / Q000008:administration & dosage; D004938:Esophageal Neoplasms / Q000188:drug therapy / Q000401:mortality / Q000601:surgery*; D016629:Esophagectomy / Q000401:mortality; D005260:Female; D005472:Fluorouracil / Q000008:administration & dosage; D006761:Hospitals / Q000706:statistics & numerical data*; D006801:Humans; D007564:Japan; D008297:Male; D008875:Middle Aged; D015233:Models, Statistical; D020360:Neoadjuvant Therapy; D011183:Postoperative Complications / Q000453:epidemiology / Q000209:etiology*; D015996:Survival Rate; D016896:Treatment Outcome
chemical_list: D000970:Antineoplastic Agents; D002945:Cisplatin; D005472:Fluorouracil