Evaluation of the breast cancer mortality in the German Mammography Screening Program: Main study - 2nd part
Description
- The Mammography Screening Program (MSP) has been introduced nationwide in Germany since 2009. Following the introduction of the program, various options for investigating the effectiveness of this program in reducing breast cancer mortality were explored as part of the program's regulatory mandate. In this context, the project ZEBRA-HS-II was conducted.
Most of the analyses of the ZEBRA-HS-II project at BIPS were conducted as a cohort study on the basis of so-called secondary data (i. e., the data were collected in a different context and will be used 'secondarily' for this project). The data maintained at BIPS comprising a Germany-wide sample of pseudonymized insured persons from the statutory health insurance (SHI) played a central role. In the already completed feasibility phase of this project (Mach I and Mach II; see links below), our institute was able to demonstrate the basic suitability of these data for the planned analyses. In the first part of the main phase of the project (ZEBRA-HS-I; see link below), the data basis and the methods of analysis were developed for the analyses planned in the second part of the main study, which has been completed at the end of 2024, comparing breast cancer mortality in MSP participants and non-participants. As the endpoint under consideration in this study (breast cancer mortality) is a relatively rare event, a very large study population had to be included for an accurate estimate of a potential effect of MSP. In addition, an effect of the MSP would not be measurable at the population level until approximately 6–10 years after screening participation, requiring a long follow-up of the study population.
It was a particular challenge for the analyses to account for the fact that women who participate in screening differ from non-participants in terms of risk factors, among other things. Any resulting selection bias had to therefore be considered in the statistical analyses. An appropriate study protocol capable of adequately accounting for these aspects has been developed in ZEBRA-HS-I and was published in 2022.
In the current project phase ZEBRA-HS-II, BIPS is primarily working on the following tasks:
• Implementation of the analyses planned in the study protocol
• Operationalization of an Emulated Target Trial-approach for the analysis on the basis of the created SHI-database
• Implementation of the analyses on breast cancer mortality and coordination of these analyses with cooperation partners in the project
• Evaluation of the results
For the analyses, the data years 2004 to 2018 were included. The cause of death missing in the SHI data was added on the one hand by linkage to data from cancer registries and on the other hand by using an algorithm based on SHI data, which was validated based on official cause of death information.
Funding period
- Begin: December 2021
End: December 2024
Sponsor
- Federal Office for Radiation Protection
Contact
Project management (national)
- Dr. Heike Minnerup, Institut für Epidemiologie und Sozialmedizin, Westfälische Wilhelms-Universität Münster
Links
Selected project-related publications
- Heinze F, Langner I, Bartholomäus S, Meyer M, Kieschke J, Maaser K, Czwikla J. Enrichment of health insurance claims data with official death certificate information from three German cancer registries: Proportions of successful linkages and differences by region, year, and age. Das Gesundheitswesen. 2025; (Epub 2025 Mar 13).
https://doi.org/10.1055/a-2531-6220 - Braitmaier M, Kollhorst B, Heinig M, Langner I, Czwikla J, Heinze F, Buschmann L, Minnerup H, García-Albéniz X, Hense H-W, Karch A, Zeeb H, Haug U, Didelez V. Effectiveness of mammography screening on breast cancer mortality - A study protocol for emulation of target trials using German health claims data. Clinical Epidemiology. 2022;14:1293-1303.
https://doi.org/10.2147/CLEP.S376107