title: [The value of ipsilateral breast tumor recurrence as a quality indicator: hospital variation in the Netherlands].
abstract: OBJECTIVE
  All Dutch hospitals are obliged to report their 5-year ipsilateral breast tumor recurrence (IBTR) rate after breast cancer surgery. Experts decided that these rates should not exceed 5%. This study determined the value of IBTR as an indicator to compare quality of care between hospitals.
  
  
  METHODS
  Cohort study
  
  
  METHODS
  All patients with breast cancer (pT1-3, any N, M0) who underwent surgery in 1 of 92 Dutch hospitals from 2003 to 2006 were identified in the Netherlands Cancer Registry. Data of recurrence was retrieved from hospital records. Five-year IBTR rates for breast-conserving surgery (BCS) and mastectomy were calculated using the Kaplan-Meier method. Hospital variation was presented in funnel plots . Multivariate analysis was used to assess hospital characteristics associated with IBTR rates.
  
  
  RESULTS
  A total of 40,892 breast cancer patients were included. The overall 5-year IBTR rate was 2.85% (95%-CI 2.68-3.03) and was significantly lower for BCS than for mastectomy (2.38% vs 3.45%, p < 0.001). IBTR rates decreased over time in both groups. Rates varied between 0.77 and 5.70% between hospitals. When random variation is taken into account, only extremely high IBTR rates can be detected as deviant from the target value of 5%. Adjusting for tumor and patient characteristics, analyses showed that a higher volume of mastectomies is associated with lower IBTR rates.
  
  
  CONCLUSIONS
  Our population-based findings show that IBTR rates in the Netherlands are low and have improved over time. The 5-year IBTR rate as an indicator for quality of care of individual hospitals is of limited value.
authors.affiliation: *Dit onderzoek werd eerder gepubliceerd in Annals of Surgical Oncology (2015;(suppl 3):522-8) met als titel 'The value of ipsilateral breast tumor recurrence as a quality indicator: hospital variation in the Netherlands'. Afgedrukt met toestemming.
authors.forename: Margriet
authors.initials: M
authors.lastname: van der Heiden-van der Loo
authors.forename: Sabine
authors.initials: S
authors.lastname: Siesling
authors.forename: Michel W J M
authors.initials: MW
authors.lastname: Wouters
authors.forename: Thijs
authors.initials: T
authors.lastname: van Dalen
authors.forename: Emiel J T
authors.initials: EJ
authors.lastname: Rutgers
authors.forename: Petra H M
authors.initials: PH
authors.lastname: Peeters