title: [Effects of guideline-compliant therapy on the survival of primary breast cancer patients with: results of a retrospective cohort study].
abstract: OBJECTIVE
  The development and implementation of the "Interdisciplinary S3 Guideline for the Diagnosis, Treatment and Follow-up Care of Breast Cancer" (3) is intended to optimise national health services. This guideline already serves both as a basis for the certification of German breast centres and for the external comparative quality assurance based on guideline based quality indicators. Nevertheless, the effects of the implementation on relevant outcomes have not been examined so far.
  
  
  METHODS
  The retrospective cohort study analyses data of 3,976 female patients with primary breast cancer which were collected at the University of Ulm and co-operating certified breast centres between 2001 and 2005. Based on the S3 guideline, an analysis model was developed to allow for the examination of guideline-adherent therapy on the basis of the guideline recommendations, and the effects of guideline-adherent compared to not guideline-adherent therapy on overall (OAS) and recurrence-free survival (RFS) were examined subsequently.
  
  
  RESULTS
  In total, 2,063 (51.9%) of the 3,976 patients were treated in adherence the guideline. In 1,913 (48.1%) patients deviations from the guideline recommendations in at least one of the therapeutic options were found. The variable "guideline-adherent treatment" had significant influence on RFS [p < 0.001; HR=2.20; 95% CI (1.74 to 2.79)] and OAS (p < 0.001; HR=2.57; 95% CI (1.96 to 3.37)], each adjusted for age, tumour size, nodal status and grading. RFS decreases with the number of deviations from guideline recommendations [1 to 2 deviations: p < 0.001; HR=2.04; 95% CI (1.60 to 2.60); ≥ 3 deviations: p < 0.001; HR=3.64; 95% CI (2.43 to 5.45), also adjusted for age, tumour size, nodal status and grading]. Similar results were found for the OAS.
  
  
  CONCLUSIONS
  Patients with breast cancer should be treated in adherence to guideline recommendations. Deviations and barrier factors will have to be evaluated in the future in order to further optimise both the guideline and guideline-adherent therapy.
authors.affiliation: Universität Bremen, Fachbereich Mathematik und Informatik.
authors.forename: Regine
authors.initials: R
authors.lastname: Wolters
authors.forename: Achim
authors.initials: A
authors.lastname: Wöckel
authors.forename: Manfred
authors.initials: M
authors.lastname: Wischnewsky
authors.forename: Rolf
authors.initials: R
authors.lastname: Kreienberg
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001943:Breast Neoplasms / Q000401:mortality* / Q000473:pathology / Q000628:therapy*; D002173:Cancer Care Facilities; D015331:Cohort Studies; D003131:Combined Modality Therapy; D003299:Cooperative Behavior; D019317:Evidence-Based Medicine; D005260:Female; D005858:Germany; D019983:Guideline Adherence; D006801:Humans; D033183:Interdisciplinary Communication; D008207:Lymphatic Metastasis / Q000473:pathology; D008297:Male; D008875:Middle Aged; D009313:National Health Programs; D009367:Neoplasm Staging; D017410:Practice Guidelines as Topic; D012189:Retrospective Studies; D015996:Survival Rate; D047368:Tumor Burden