Trends Over Time in Breast-Cancer-Specific Mortality in Germany
After the guidelines for cancer screening were changed in 2003, nationwide mammography screening was implemented in Germany, based on the European guidelines for quality assurance in breast cancer screening and diagnosis (1). Since 2005 women aged between 50 and 69 who are insured in statutory health insurance schemes have been entitled to undergo mammography screening every two years. The overriding objective of introducing screening was to lower breast cancer specific mortality. To date, the benefits and harms of screening remain the subject of controversial debate. From a scientific perspective, (older) randomized controlled trials and observational studies are cited as the evidence base (the Canadian Breast Cancer Screening Study, the Health Insurance Plan of Greater New York (HIP) trial, Stockholm trial, Malmö Mammographic Screening Trial, Gothenburg trial, and Swedish Two-County Study) and differently evaluated by author group (2). In recent times doubt has arisen regarding whether mortality reducing effects that were mainly observed in the 1970s and 1980s can still be achieved today on a background of improved therapeutic options. For this reason, analyzing recent observational data is of particular importance.
Screening related reductions in mortality should be seen not only at the level of the participants but also at the population level. The expectation would also be that a fall in breast cancer mortality is accompanied by a fall in diagnosed late stage cancers. Both effects would be seen primarily in the age group entitled to screening investigations and not—or only to a lesser degree—in other age groups.
Katalinic et al reported in 2019 that when comparing the years 2003/2004 and 2015/2016 the incidence of stage IV tumors in 50–59 year old women fell by 23.0% and in 60–69 year old women by 24.2%. In other age groups the incidence had not fallen or at least not to the same extent. Regarding breast cancer mortality, a statistically significant reduction of 25.8% was described in 50–59 year old women and of 21.2% in 60–69 year old women (age group 40–49: −16.1%; 70–79: −2.5%) (3).
We studied whether the observed mortality trends continued on the basis of population data up to the year 2018.
Material and methods
Population and mortality data from 2003 to 2018 were accessed via the Information System of the Federal Health Monitoring database (www.gbe-bund.de, last accessed 8 January 2021).
Age specific rates were reported for six age groups (entitled to screening: 50–59, 60–69; not entitled 20–39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, and ≥ 80 years). Differences were reported as absolute and relative differences between rates in the prescreening period (mean 2003/2004) and the available most recent two tears (2017/2018). We used joinpoint regression models to analyze trends (SEER Joinpoint software 22.214.171.124; model selection took place by weighted “Bayesian information criterion,” BIC). Joinpoint regressions determine stepwise log-linear regression straight lines and provide estimates of the annual percentage change (APC) and their 95% confidence intervals. A maximum of three joinpoints was permitted.
The trend analysis showed a fall in mortality in almost all age groups up to about 2007–2010, with the biggest drops in the age groups 20–39, 40–49, and 50–59 years (Figure). The trends subsequently changed. Falls in the age groups entitled to screening examinations continued to be observed (50–59 years: APC −1.6% [−0.8; −2.3]); 60–69 years: APC −2.7% [−2.1; −3.2]). Mortality rates in 2017/2018 in the screening relevant age groups were 28.8% and 23.6% lower than in the prescreening period. From 2008 or 2007 onwards, rises in mortality rates were observed in the two oldest age groups (70–79 years: APC 0.5% [0; 0.9]; ≥ 80 years: APC 1.8% [1.4; 2.1]). The relative rate increase in women aged 80 or older was 14.2%.
As described earlier for the period up to 2016 (3), the drop in mortality in the screening relevant age groups continued until 2018. The mortality rate in the 70–79 age group is still slightly below the rate from the prescreening period, but has increased slightly since 2008 (APC: 0.5%; [0; 0.9]). In the age group ≥80, the increase in mortality in the post-implementation phase is an annual percentage change of 1.8% [1.4; 2.1]. The reason for this is not known.
For the older age groups it should be borne in mind that participation in mammography screening was—if applicable—not possible or possible to a limited degree only, since women in the older age groups were already too old to participate in screening when the program was introduced in 2005.
Looking at the age group of 70–79 year olds in isolation (data not shown), who before 2018 were able to participate in six screening rounds, reveals a continuous drop in mortality. Altogether the continuing mortality reduction in the screening age groups indicates an effect of mammography screening, whereas in other age groups stagnation or even an increase was observed.
Currently, an expansion of the screening program to include younger (<50 years) and older ((≥70 years) women is under discussion and being investigated in studies (for example 4, 5]). A group of experts from the European Commission (ECIBC) considers the existing evidence as sufficient. The currently lacking mortality drop in these age groups should, however, prompt such a discussion in Germany too.
Annika Waldmann, Joachim Hübner, Alexander Katalinic
Conflict of interest statement
Prof Dr Katalinic is the chair of the scientific advisory board of the German Breast Cancer Screening Program
Dr Dr Hübner received author or co-author fees in the context of a publication with a connection to the subject matter, from Springer publishers.
The remaining authors declare that no conflict of interest exists.
Manuscript received on 18 January 2021, revised version accepted on 5 March 2021.
Translated from the original German by Birte Twisselmann, PhD.
Cite this as:
Waldmann A, Hübner J, Katalinic A:
Trends over time in breast-cancer-specific mortality in Germany.
Dtsch Arztebl Int 2021; 118: 538–9.
University of Lübeck, Institute for Cancer Epidemiology e. V. (Katalinic)
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Der Onkologe, 202110.1007/s00761-021-01059-7