The Challenge of Calculating EUSOMA Quality Indicators with Administrative Data: A Pilot Study in Belgium.

Introduction: The study aimed to assess the feasibility of calculating the European Society of Breast Cancer Specialists (EUSOMA) quality indicators (QIs) using Belgian Cancer Registry data coupled to administrative health data and to provide national results. Methods: Women diagnosed with ductal carcinoma in situ (DCIS) or invasive breast cancer (IBC) in 2014-2018 were selected from the cancer registry. Fourteen EUSOMA QIs were chosen to assess the quality of care. Results: Overall, 46,035 patients with IBC and 3,973 patients with DCIS were included. Most QIs had to be rephrased so that they could be calculated with the available data. None of the selected QIs on systemic treatment could be calculated due to a lack of reliable receptor status information. For some Qis, there is ample room for improvement in Belgian clinical practice: cTNM stage reporting, multidisciplinary team meetings, sentinel lymph node biopsy only in IBC with clinically negative lymph nodes. The result was 1-5% lower than the target for mammography and breast ultrasound, pTNM reporting, start of treatment, single breast surgery in DCIS, and no axillary clearance in DCIS. For histological or cytological assessment, receptor status assessment, start of radiotherapy, and single breast surgery in IBC, the results were at or above the target. Conclusion: Several EUSOMA QIs can be calculated with routinely collected data, while for several important aspects of care additional data collection is indicated so that its quality can be assessed. The validity of the obtained results depends on the reporting accuracy.