Annelotte van Bommel

81 Organizational factors affect the use of immediate breast reconstruction cancer (0–0.5, 0.5–2.5 and > 2.5), number of breast surgeons available at the institution per 100 new diagnoses of breast cancer (0–1.5, 1.5–2.5 and >2.5) and the presence of a plastic surgeon at the weekly MDT meeting (never/incidental, structural). “Never” refers to hospitals where no plastic surgeon was attending the weekly MDT meetings and “incidental” only incidentally on request. Only patients of hospitals that responded to the survey were included for analyses. In case data were missing, we categorized them as unknown. Statistical analyses DCIS and invasive breast cancer were analyzed separately. Factors tested for confounding were age, social economic state (SES), multifocality, clinical tumor stage, clinical lymph node stage, grade and radiation therapy. With use of a logistic regression model hospital organizational factors were related to the prevalence of IBR and were presented as odds ratio’s with 95% confidence intervals (95%CIs). Factors that demonstrated to significantly affect IBR rates in univariable analyses (p <0.10) were included in the multivariable analyses. Hospital performance of IBR was visualized with the use of funnel plots. In the funnel plots the volume is based on the number of mastectomies (and not the total number of breast cancer diagnosis treated per hospital) over 3 years. Actually, in the Netherlands, 60% of the patients are treated with breast conserving surgery, so the actual hospital volume of breast cancer patients is much higher. Data were analyzed unadjusted and adjusted for patient, tumor and hospital organizational factors significantly affecting the use of IBR. Since the data is organized at more than one level and is clustered for the individual hospitals, multilevel analysis was performed. Not all organizational characteristics of the hospitals were known, but with use of a multilevel analysis, all hospital depending factors were taken into account in the adjusted data. All statistical analyses were performed in STATA (version 13.1 2013, Texas). 5