title: DBCG trial 89B comparing adjuvant CMF and ovarian ablation: similar outcome for eligible but non-enrolled and randomized breast cancer patients.
abstract: BACKGROUND
  A cohort of premenopausal patients with primary hormone receptor positive breast cancer was prospectively identified to be eligible for the DBCG 89B trial. We perform a long-term follow-up and evaluate the external validity of the trial.
  
  
  METHODS
  Following registration in a population-based registry, patients were invited to be randomized to ovarian ablation (OA) versus nine courses of three-weekly cyclophosphamide, methotrexate and 5-fluorouracil (CMF). The same procedures were used in all patients, including report forms, central review, querying, and analysis of data. Multivariate analysis was used to adjust for differences in base-line characteristics.
  
  
  RESULTS
  Participation in the randomization varied according to center and time period. One thousand six hundred and twenty eight eligible patients were registered and 525 randomized in the DBCG 89B trial. Median estimated follow-up was 9.5 years for disease-free survival and 12.1 years for overall survival. Non-enrolled patients had a disease-free and overall survival similar to randomized patients. Within 5 years of surgery, results were similar following OA and CMF, but disease-free survival was significant inferior with OA more than five years after surgery, adjusted hazard ratio 1.38 (95% CI 1.03 to 1.85; p=0.03). This convened ten years after surgery to an inferior survival with OA, and the adjusted hazard ratio was 2.37 (95% CI 1.43 to 3.91; p<0.01).
  
  
  CONCLUSIONS
  This prospective cohort study indicates that eligible patients not participating in the DBCG 89B trial had a similar disease-free and overall survival as participants. Survival was similar after OA and CMF in the first ten years, but became inferior in the OA group 10 or more years after surgery.
authors.affiliation: Department of Oncology, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark.
authors.forename: Bent
authors.initials: B
authors.lastname: Ejlertsen
authors.forename: Maj-Britt
authors.initials: MB
authors.lastname: Jensen
authors.forename: Henning T
authors.initials: HT
authors.lastname: Mouridsen
authors.forename: Jørn
authors.initials: J
authors.lastname: Andersen
authors.forename: Søren
authors.initials: S
authors.lastname: Cold
authors.forename: Erik
authors.initials: E
authors.lastname: Jakobsen
authors.forename: Claus
authors.initials: C
authors.lastname: Kamby
authors.forename: Peter G
authors.initials: PG
authors.lastname: Sørensen
authors.forename: Marianne
authors.initials: M
authors.lastname: Ewertz
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000008:administration & dosage / Q000009:adverse effects / Q000627:therapeutic use*; D001943:Breast Neoplasms / Q000188:drug therapy / Q000601:surgery / Q000628:therapy*; D017024:Chemotherapy, Adjuvant; D015331:Cohort Studies; D003520:Cyclophosphamide / Q000008:administration & dosage / Q000009:adverse effects; D005260:Female; D005472:Fluorouracil / Q000008:administration & dosage / Q000009:adverse effects; D005500:Follow-Up Studies; D006801:Humans; D008727:Methotrexate / Q000008:administration & dosage / Q000009:adverse effects; D008875:Middle Aged; D010052:Ovariectomy; D010053:Ovary / Q000502:physiology* / Q000528:radiation effects / Q000601:surgery; D015996:Survival Rate; D016896:Treatment Outcome
chemical_list: D003520:Cyclophosphamide; D005472:Fluorouracil; D008727:Methotrexate