Introduction/Background Breast cancer (BC) is one of the most common tumours in the globe. Since 2011, BC in Kazakhstan has been ranked first in the structure of the overall cancer incidence and 4 in the structure of the overall cancer mortality. Since 2008, population BC screening has been introduced among women 50–60 years old with an interval of 2 years. In 2014, 80% of mammography devices were digitized. Since 2018, the screening age has been extended to 40–70 years.
Methodology The following screening indicators were analyzed: the cancer detection rate (CDR), the proportion of 0–1 stages (since 2011), the interrelation with the dynamics of morbidity and mortality. According to the levels of morbidity (average annual rate for 2004–2007), the regions of the country are divided into three groups: A - high (23.2–30.8 per 100 000 population), B - mid (18.4%ooo-22.5%ooo), and C - low (13, 2–15.18%ooo) rate.
In total, over 12 years of screening, 5,763,518 women were examined, 9,323 cases of BC were identified. Coverage to the targeted population ranged from 82% in 2012 to 47.5% in 2018. Since 2011, BC screening cases (8 330) have been compared with the cancer registry.
Results Average CDR in 2011–2019 was 0.18%, in groups A - 0.23%, B - 0.20% and C - 0.14%. The share of 0-I stages was 36.2%, in groups A - 39.9%, B - 29.9% and C - 22.1%.
The average annual baseline morbidity (2004–2007) was in groups A - 26.6 per 100 000 population, B - 21.2%ooo and C -14.3%ooo. Before digitalization (2008–2014), the average annual morbidity in groups was: in A - 30.5%ooo, B - 22.8%ooo, C - 16.5%ooo, after digitalization, respectively 31.5, 23.8 and 18.7.
The greatest increase of morbidity was noted in groups A and C (20.6% and 30.7%), less in group B (12.4%). Screening increased the incidence since 20.8%ooo in 2008 till 25.3 in 2018 and slightly reduced the mortality rate from 8.5 (2008) to 6.8 (2018) per 100 thousand of the population.
Conclusion Over the 12 years of screening in Kazakhstan, the BC incidence has increased and mortality has decreased. Regions with a high baseline morbidity had higher CDRs by screening, especially in the first years, as well as high levels of BC detection in stage 0-I. It is possible that radiologists have better skills and women’s cancer awareness is higher in regions with a high cancer incidence.
For regions with different BC incidence rates, it is necessary to identify indicators to assess of the effectiveness and improve the quality of screening.
Disclosures The authors have no financial conflicts of interest.
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