Evaluation of breast cancer mortality in the German Mammography Screening Program - Feasibility study


ZEBRA – Mach I
Evaluation of Breast Cancer Mortality in the German Mammography-Screening-Program
(Feasibility study I)

In 2005, a breast cancer screening program was introduced in Germany. The Federal Ministry of Environment, Conservation and Reactor Safety and the Federal Office for Radiation Protection advocated that high standards of quality be implemented in this program. Besides aspects of quality management and control, questions concerning the evaluation of the screening program with respect to the long term effects on breast cancer mortality in Germany are also of importance.
To this end, the Federal Office for Radiation Protection commissioned the ZEBRA-consortium, under the leadership of the University of Münster, to conduct a feasibility study for the evaluation of the mammography screening program. In this feasibility study, the project partners, amongst them the BIPS, are supposed to develop and test concepts which enable the analysis of the effectiveness of the screening program using epidemiological methods. The evaluation is to be based on secondary individual data and data protection principles are to be taken into consideration. These concepts should then be applied in a main study.
The BIPS, together with the SOCIUM at the Bremen University, was responsible for the development and testing of concepts based on secondary data from statutory health insurance companies. The advantage of these data is that they also include information on mammography examinations conducted outside the framework of the screening program. In addition, information on women not participating in the screening program is also included. However, some limitations are also associated with this data source, amongst others the lack of information on the cause of death. During the two-year project time (2012 to 2014), the feasibility of using claims data for the evaluation of the screening program was initially explored.
Our institute could show that based on claims data and subject to terms of current data protection regularities, analyses for an evaluation of the screening program are feasible. The necessary data can be included from past, current, and future time periods with unchanged quality. The data give a representative cross section of the 50- to 69-year-old women eligible to take part in the mammography screening program (MSP). Cases of prevalent breast cancer (these are not eligible to participate) can be excluded from the study population on the basis of physician diagnoses, and MSP participants and non-participants can be followed up for a sufficiently long period until the outcome 'death', which will be observed in the evaluation. To date, the addition of individual cause of death information failed due to legal barriers. First analyses for total mortality of the study population showed that participation in the MSP leads to a strong selection bias. This was evident in the considerably lower total mortality in participants compared to non-participants: as this is apparent already one year after participation, this effect can not be attributed to the MSP participation. It is to be expected that a corresponding bias between participants and non-participants will also be present for breast cancer mortality., This has to be accounted for in the evaluation study of the MSP through the utilization of adequate methods for the analysis design to enable meaningful interpretation of the results. The development of such analytical approaches as well as the efforts to enrich the claims data with cause of death information were further pursued in the project "Evaluation der Brustkrebsmortalität im deutschen Mammographie-Screening-Programm (Machbarkeitsstudie II) – ZEBRA 2".

Funding period

Begin:   July 2012
End:   September 2014


  • Federal Office for Radiation Protection


Prof. Dr. med. Hajo Zeeb

Project management

Prof. Dr. Hans Werner Hense, Universität Münster


  • Dr Klaus Giersiepen (Zentrum für Sozialpolitik (ZeS), Universität Bremen)
  • Dr. Oliver Heidinger (Epidemiologisches Krebsregister NRW gGmbH)
  • Prof. Dr. Walter Heindel (Institut für Klinische Radiologie, Medizinische Physik, Universität Münster)
  • Prof. Dr. Hans Werner Hense (Institut für Epidemiologie und Sozialmedizin, Westfälische Wilhelms-Universität Münster)
  • Prof.Dr. Stefanie Klug (Universitäts KrebsZentrum, Dresden)
  • Prof. Dr. Heinz Rothgang (Zentrum für Sozialpolitik (ZeS), Universität Bremen)