Annelotte van Bommel

21 The NABON Breast Cancer Audit Quality indicators: monitoring of the structure, process and outcome of breast cancer care Quality indicators are as much evidence-based as possible. These quality indicators are used to evaluate guideline adherence and outcomes of breast cancer care and they cover different aspects of the multidisciplinary care path for breast cancer patients, from diagnostic work-up to the different treatment options. For 2015, 32 quality indicators measuring structure, processes and outcomes of breast cancer care are available for benchmarked feedback and public transparency. Each indicator consists of a nominator and a denominator, the latter describing the selection of patients under consideration ( Supplementary Appendix 1 ). For 10 indicators, a professional standardized norm is available, that is, a generally accepted cut-off value, implying that a hospital should perform above (e.g., in case of pre-operative multi-disciplinary team [MDT] meeting) or below (e.g., in case of tumor-positive margins) a predefined standard. These norms are based on consensus of the multidisciplinary scientific committee. For some indicators, such as tumor-positive margins, norms are based on national guidelines/international literature. For other indicators, where total adherence was expected and desirable, thresholds were set at 90%. Other indicators were merely defined to explore institutional variation in treatment patterns. Standardized cut-off values denominating a level of quality are not (yet) available for these indicators. The NBCA quality indicators are evaluated annually by the scientific committee on their validity and existing indicators may be adapted or removed when considered redundant whereas new indicators are developed based on new insights. Currently, some indicators are merged (pre- and post-operative MDT meeting with a more strict norm), others are deleted (estrogen and progesterone receptor positivity), while others are adjusted (such as the frequency of tumor-positive margins which will be presented in relation to the proportion of patients who subsequently undergo re-excisions). Dataset and registration of NBCA data All surgically treated patients diagnosed with primary invasive breast cancer or ductal carcinoma in situ (DCIS) in the Netherlands are included in the NBCA. Patients diagnosed with lobular carcinoma in situ, phyllodes tumors, sarcomas and lymphomas are not included. Patients are included based on the date of the 2