Comparison of female breast cancer between Russia and Germany: A population-based study on time trends and stage at diagnosis

1Introduction

Female breast cancer was the leading cause of global cancer incidence in 2020. Incidence rates are estimated to be generally higher in Western-European countries (90.7/100,000 population) than in Eastern Europe (57.1/100,000 population) [1] . A study from Russia observed increasing breast cancer age-standardised incidence rates over the past decades from 33.0 to 47.0 per 100,000 (1993–2013) [2] . Similarly, the latest report from Germany showed that incidence rates increased by 48.1 % between 2005 and 2016 [3] . In Germany, one out of eight women is estimated to develop breast cancer during her lifetime [4] .

The main reasons for increasing breast cancer rates are widely discussed. Obesity has reached an epidemic proportion in Russia and is showing a rising trend as a consequence of the adoption of western dietary patterns and less physical activities [56] . In addition, reproductive risk factors like earlier age at menarche [7] and declining fertility rates [2] are reported from Russia. Similarly, the increasing incidence in Germany likely reflects changes in the prevalence of hormonal and reproductive risk factors, lifestyle risk factors, as well as increased early detection through organised or opportunistic mammographic screening [1] .

The Russian health system inherited its infrastructure from the Soviet Union. In each region, the administration has a health department that monitors regionally owned health facilities and observes municipal-level health departments. To date, there is no national body in charge of the prevention and monitoring of non-communicable diseases. However, a network of preventive health centres was established in 2010, in charge of promoting healthy lifestyles [8] . Cancer screening programmes are known to be opportunistic and lack overall coordination [9] . Opportunistic programmes provide screening to women on request or due to the presence of another illness or an increased risk of breast cancer in the family [10] . Starting from 2013, the dispanserizatsiya (periodical health check of adults) has been included in the compulsory health insurance system in the Russian Federation. In the frames of the dispanserizatsiya , mammography had been offered to women aged 39–75 once in three years and, starting from 2018, every two years [11] .

Germany’s health system ensures access to high-quality care through Universal Health Care coverage, with about 90 % of the population covered by the statutory health insurance system. A large part of the remaining population in Germany has private health insurance and there are only few uninsured people. In 2008, the German National Cancer Plan was initiated, involving all relevant stakeholders and national experts in cancer control [12] . The German mammography-screening program (MSP) is being offered systematically to all statutory and private health insurance members. The MSP was implemented between 2005 and 2009 depending on the region, inviting women aged 50–69 years every second year [13] . There are 94 MSP units across the country, with each covering about 0.5–1 million population. At the federal state level, centres are responsible for inviting women by mail to participate in the programme. Since the year 2009, the participation has been about 50 % [14] . The programme complies with the quality process indicators of the European guidelines on breast cancer screening [15] .

The stage of breast cancer at diagnosis is a major determinant of overall survival and reflects many indicators, such as awareness of cancer symptoms, timely diagnosis, and the effectiveness of screening programmes [16] . Several epidemiological trends are to be expected when a MSP is introduced: Initiated by a short-term increase in incidence with a following decline in overall and late-stage breast cancer incidence below pre-screening levels after several years [17] .

This study aimed to gain further insights into the development of epidemiological markers associated to the effectiveness of early detection efforts for breast cancer in Russia during a period when there was no state-operated opportunistic screening. To do so, we examined trends of stage at diagnosis in two Russian regions and compared the results with the development in Germany before and after the implementation of the MSP.