Breast Cancer in Megapolises of Kazakhstan: Epidemiological Assessment of Incidence and Mortality

Background: Breast cancer is the most common malignant disease among the female population of Kazakhstan like in many developed countries of the world (Canada, UK, US, Western Europe), and it accounts for every 5th tumor. We aimed to assess the epidemiological aspects of breast cancer incidence and mortality among Almaty and Astana (Now Nur-Sultan), Kazakhstan residents in 2009-2018. Methods: A retrospective study using modern descriptive and analytical methods of epidemiology was conducted to evaluate the breast cancer incidence and mortality in megapolises of Kazakhstan. Results: The average annual age-standardized incidence rate of breast cancer amounted to 61.9(sic) (95% CI=56.2-67.6) in Almaty and 61.2(sic) (95% CI=56.765.7) in Astana. The average age-standardized mortality was 19.2(sic) (95% CI=17.3-21.1) in Almaty and 19.3(sic) (95% CI=17.1-21.4) in Astana. The standardized incidence in the megapolises tended to increase (T-gr=+0.8% in Almaty and T-gr=+1.4% in Astana), while the mortality was decreasing (T-dec=-4.2% in Almaty and T-dec=-1.1% in Astana). According to the component analysis, the growth in the number of breast cancer cases was due to a population increase (Delta(P)=+130.4% in Almaty and Delta(P)=+93.2% in Astana), with a notable decrease of factors related to the risk of getting sick (Delta(R)=-27.9% in Almaty, Delta(R)=-6.1% in Astana). Conclusion: This is the first epidemiological study to assess the changes in incidence and mortality from breast cancer in megapolises of Kazakhstan because of screening. The results of this study can be used to improve the government program to combat breast cancer.