Effectiveness of Mammography Screening on Breast Cancer Mortality – A Study Protocol for Emulation of Target Trials Using German Health Claims Data

Abstract

Malte Braitmaier,1 Bianca Kollhorst,1 Miriam Heinig,2 Ingo Langner,2 Jonas Czwikla,3 Franziska Heinze,3 Laura Buschmann,4 Heike Minnerup,4 Xabiér García-Albéniz,5,6 Hans-Werner Hense,4 André Karch,4 Hajo Zeeb,7,8 Ulrike Haug,2,8 Vanessa Didelez1,9 1Department of Biometry and Data Management, Leibniz Institute for Prevention Research and Epidemiology – BIPS, Bremen, Germany; 2Department of Clinical Epidemiology, Leibniz Institute for Prevention Research and Epidemiology – BIPS, Bremen, Germany; 3SOCIUM Research Center on Inequality and Social Policy, University of Bremen, Bremen, Germany; 4Institute for Epidemiology and Social Medicine, Faculty of Medicine, Westfälische Wilhelms University of Münster, Münster, Germany; 5Department of Epidemiology, Harvard T. H. Chan School of Public Health, Boston, MA, USA; 6RTI Health Solutions, Barcelona, Spain; 7Department of Prevention and Evaluation, Leibniz Institute for Prevention Research and Epidemiology – BIPS, Bremen, Germany; 8Faculty of Human and Health Sciences, University of Bremen, Bremen, Germany; 9Faculty of Mathematics and Computer Science, University of Bremen, Bremen, GermanyCorrespondence: Vanessa Didelez, Leibniz Institute for Prevention Research and Epidemiology – BIPS, Department of Biometry and Data Management, Achterstraße 30, Bremen, 28359, Germany, Tel [phone], Fax [phone], Email [email protected]: The efficacy of mammography screening in reducing breast cancer mortality has been demonstrated in randomized trials. However, treatment options - and hence prognosis – for advanced tumor stages as well as mammography techniques have considerably improved since completion of these trials. Consequently, the effectiveness of mammography screening under current conditions is unclear and controversial. The German mammography screening program (MSP), an organized population-based screening program, was gradually introduced between 2005 and 2008 and achieved nation-wide coverage in 2009.Objective: We describe in detail a study protocol for investigating the effectiveness of the German MSP in reducing breast cancer mortality in women aged 50 to 69 years based on health claims data. Specifically, the proposed study aims at estimating per-protocol effects of several screening strategies on cumulative breast cancer mortality. The first analysis will be conducted once 10-year follow-up data are available.Methods and Analysis: We will use claims data from five statutory health insurance providers in Germany, covering approximately 37.6 million individuals. To estimate the effectiveness of the MSP, hypothetical target trials will be emulated across time, an approach that has been demonstrated to minimize design-related biases. Specifically, the primary contrast will be in terms of the cumulative breast cancer mortality comparing the screening strategies of “never screen” versus “regular screening as intended by the MSP”.Ethics and Dissemination: In Germany, the utilization of data from health insurances for scientific research is regulated by the Code of Social Law. All involved health insurance providers as well as the responsible authorities approved the use of the health claims data for this study. The Ethics Committee of the University of Bremen determined that studies based on claims data are exempt from institutional review. The findings of the proposed study will be published in peer-reviewed journals.Keywords: emulated target trial, cancer screening, effectiveness, claims data, mammography

Keywords

• emulated target trial
• cancer screening
• effectiveness
• claims data
• mammography