Annelotte van Bommel

35 The NABON Breast Cancer Audit adjuvant chemotherapy it is recommended to performbreast MRI prior to the start of therapy as the optimal means to monitor response to treatment). 18 Apparently, interpretation of this definition varies between hospitals as demonstrated by the observed variation. Another example is the proportion of patients undergoing an immediate reconstruction following a mastectomy for invasive breast cancer or DCIS and variation in neo-adjuvant chemotherapy. The NBCA may serve as a database to identify factors explaining the observed hospital variation. Identifying areas of variation provides insight, opens discussions among clinicians and enables further research to understand the variation, allowing future guideline recommendations and improving quality of care for all breast cancer patients. Limitations Participation of all hospitals in the audit enables valid comparisons. However, completeness of the data by all participating hospitals is required in order to understand observed differences. Especially in the first year of registration, not all data were complete or correctly coded in the system. For example, it was difficult to retrieve from hospital records by IKNL-trained registrars whether a patient was discussed in anMDTmeeting in the first year of registration. We chose not tomake missing data an advantage; in case that a hospital had not reported if patients were discussed in an MDT meeting, it was assumed that these patients were not discussed in such a meeting. The results should be interpreted within this context and can only lead to an underestimation of actual performances. Furthermore, the present results also underline that the NBCA remains “work-in-progress” as reproducible quality indicators were not available for all involved disciplines, this is expected to change within the next few years. Lastly, it is of note that the observed trends cannot be attributed fully to the audit, as these improvements may well be the result of other changes in breast cancer practice such as new operation techniques to reduce tumor-positive margins or awareness for immediate breast reconstructions. Moreover, indicators for patients without surgery should be defined and these patients should be included in future. 2