Feb. 10, 2021

Breast cancer is the most common cancer and one of the leading causes of death among women. The European Society of Breast Cancer Specialists (EUSOMA) defined quality indicators that act as an instrument for hospitals to standardize the quality assurance. Comparing quality indicators amongst countries may help to identify areas for improvement and further improve the quality of breast cancer care. We compared two countries: Norway and the Netherlands. Data from the Cancer Registry of Norway and the Netherlands Cancer Registry were used to compare some of the EUSOMA quality indicators. To have a meaningful comparison, a statistical method called “Propensity Score Stratification” was used. This technique helps to select groups of patients from the data that are comparable and therefore reduces bias due to differences in patient populations.

Traditionally, these analyses are performed by combining data from the two geographies on one machine. Vantage6 (the open source Personal Health Train implementation) allowed to keep the data locally and enable federated analyses of the Norwegian and Dutch data. Outcomes of five EUSOMA indicators were analysed and compared.

In total 39,163 female breast cancer patients were included in the study, of whom 6377 from Norway. Indicators on MRI availability, surgical approach and post-operative radio therapy were calculated and compared. In both countries four of five quality indicators were well above the minimum standard set by EUSOMA. The indicator for immediate reconstruction was below the EUSOMA threshold for both countries. Despite geographical differences, both countries offer a high quality of breast cancer care may yet improve further in the future. The application of vantage6 enabled quality comparisons between geographies without exchange of patient-level data.

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