title: Is guideline-adherent adjuvant treatment an equal alternative for patients aged >65 who cannot participate in adjuvant clinical breast cancer trials? A retrospective multi-center cohort study of 4,142 patients.
abstract: BACKGROUND
  It is well accepted that innovation in oncology is transported through randomized clinical trials (CT), furthermore there is some evidence that patients profit from participation in CT. However, especially elderly patients aged >65 usually do not have access to clinical trials; we therefore used an unselected patient cohort to investigate the following questions: (1) Is there a difference in survival parameters between study participants <65 and elderly 65-80 non-participants? (2) Is guideline-adherent adjuvant treatment an equal alternative for elderly patients aged 65-80?
  
  
  METHODS
  This German retrospective multi-center cohort study included 4,142 patients (study participants <65 and elderly breast cancer patients 65-80) with primary breast cancer recruited from 1992 to 2008 in 17 participating breast cancer centers.
  
  
  RESULTS
  Applying the exclusion criteria, we included 960 (23.2%) study participants (PA) <65 and 3,182 (76.8%) elderly >65. Elderly non-participants (NPA) >65 demonstrate a significantly inferior RFS [RFS: HR = 1.67; p < 0.001] and OS [OS: HR = 1.98; p < 0.001] compared to PA <65. Within the elderly group, 1,868 (58.7%) patients received guideline-adherent adjuvant treatment. When comparing guideline conform elderly >65 versus PA <65, we found no significant difference in RFS [RFS: HR = 1.17; p = 0.218] and OS [OS: HR = 1.34; p = 0.054]. In contrast, non-guideline-adherent elderly demonstrated significantly inferior survival parameters [RFS: HR = 2.06; p < 0.001] [OS: HR = 2.50; p < 0.001] compared to <65 PA.
  
  
  CONCLUSIONS
  Guideline-adherent adjuvant treatment seems to be an equivalent option for elderly breast cancer patients. There is a strong association between guideline adherence and improved outcome parameters in elderly breast cancer patients.
authors.affiliation: Institute for Medical Biostatistics, Epidemiology and Informatics, University Medical Centre, Johannes Gutenberg University Mainz, Obere Zahlbacher Straße 69, 55131, Mainz, Germany.
authors.forename: R
authors.initials: R
authors.lastname: Van Ewijk
authors.forename: A
authors.initials: A
authors.lastname: Wöckel
authors.forename: T
authors.initials: T
authors.lastname: Gundelach
authors.forename: K
authors.initials: K
authors.lastname: Hancke
authors.forename: W
authors.initials: W
authors.lastname: Janni
authors.forename: S
authors.initials: S
authors.lastname: Singer
authors.forename: R
authors.initials: R
authors.lastname: Kreienberg
authors.forename: M
authors.initials: M
authors.lastname: Blettner
authors.forename: L
authors.initials: L
authors.lastname: Schwentner
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D001943:Breast Neoplasms / Q000401:mortality* / Q000628:therapy*; D002986:Clinical Trials as Topic; D015331:Cohort Studies; D005260:Female; D019983:Guideline Adherence; D006801:Humans; D010358:Patient Participation; D012189:Retrospective Studies; D016019:Survival Analysis; D016896:Treatment Outcome