Annelotte van Bommel

78 ABSTRACT Objectives: Significant hospital variation in the use of immediate breast reconstruction (IBR) after mastectomy exists in the Netherlands. Aims of this study were to identify hospital organizational factors affecting the use of IBR after mastectomy for ductal carcinoma in situ (DCIS) or invasive breast cancer (BC) and to analyze whether these factors explain the variation. Materials andmethods: Patients with DCIS or primary invasive BC treatedwith mastectomy between 2011 and 2013 were selected from the national NABON Breast Cancer Audit. Hospital and organizational factors were collected with an online web-based survey. Regression analyses were performed to determine whether these factors accounted for the hospital variation. Results: In total, 78% (n=72) of all Dutch hospitals participated in the survey. In these hospitals 16,471 female patients underwent amastectomy for DCIS (n=1,980) or invasive BC (n=14,491) between 2011 and 2014. IBR was performed in 41% of patients with DCIS (hospital range 0–80%) and in 17% of patients with invasive BC (hospital range 0–62%). Hospital type, number of plastic surgeons available and attendance of a plastic surgeon at the MDT meeting increased IBR rates. For invasive BC, higher percentage of mastectomies and more weekly MDT meetings also significantly increased IBR rates. Adjusted data demonstrated decreased IBR rates for DCIS (average 35%, hospital range 0–49%) and invasive BC (average 15%, hospital range 0–18%). Conclusion: Hospital organizational factors affect the use of IBR in theNetherlands. Although only partly explaining hospital variation, optimization of these factors could lead to less variation in IBR rates.