Annelotte van Bommel

94 due to low numbers of DCIS patients we were not able to demonstrate the same significant effect of hospital organizational factors on IBR rates as for invasive breast cancer. To investigate the effect of hospital factors explaining variation in performing IBR, a multilevel analysis was performed to obtain the adjusted data for the funnel plot. The demonstrated reduction in variation after case-mix correction for patient and tumor factors was mainly caused by hospital factors. Other undefined hospital related factors could have contributed to this reduction, such as surgeons’ attitude towards IBR, gender of the (plastic) surgeon, geographical location, waiting times for plastic surgery, patient preferences and loss of control of patient’s management. 11,15 Jeevan et al. demonstrated that 50% of the patients were very satisfied with the options they received about breast reconstruction but preferred no IBR. 2 Further research should identify patient preferences and surgeon’s attitudes towards IBR and whether or not these factors can explain the variation in performing IBR completely; such studies are on its way. CONCLUSION Large hospital variation in IBR rates was observed between hospitals in the Netherlands. The current study demonstrated that the observed variation in performing IBR was significantly affected by hospital type, but also by organizational factors that could be subject for change and improvement. Although hospital variation could only be partially explained by these factors, optimization of these factors could lead to an increased use of IBR in breast cancer patients and less variation in IBR rates between hospitals.