Epidemiology of Breast Cancer Mortality in Kazakhstan, trends and Geographic Distribution.

BACKGROUND: According to the International Agency for Research on Cancer, ongoing demographic changes will lead to an increase in the number of deaths from breast cancer (BC) per year in the vast majority of regions. In 2040 it is expected that 1.04 million people worldwide will die from this malignancy, including 2,380 women in Kazakhstan. METHODS: The retrospective study (2009-2018) was done using descriptive and analytical methods of oncoepidemiology. The extensive, crude and age-specific incidence rates are determined according to the generally accepted methodology used in sanitary statistics. The data were used to calculate the average percentage change (APС) using the Joinpoint regression analysis to determine the trend over the study period. RESULTS: During 10 years 12,958 women died from BC. An average age of the death was 61.6 years (95%CI=60.6-62.6) and tended to increase (APC=+0.6%, R2=0.6117). Age-specific rates had a bimodal increase with peak rates at 70-74 years - 76.7±5.5 (APC=+3.4%, R2=0.2656) and 80-84 years - 78.0±9.1 (APC=+3.7%, R2=0.0875). The age-standardized rate was 13.9 per 100,000 of female population, and the trend has decreased. When compiling thematic maps, mortality rates were determined on the basis of standardized indicators: low - up to 12.5, average - from 12.5 to 15.2, high - above 15.2 per 100,000. The results of the spatial analysis showed the regions with a higher levels of BC mortality rate per 100,000: Pavlodar (16.9), Almaty (19.2) and Astana cities (19.3). CONCLUSIONS: Age-standardized mortality rates had a strong downward trend (APC=-4.0%, R2=0.9218). The decrease mostly is due to a large coverage of the population by mammography screening and to an improvement in the effectiveness of breast cancer treatment.

Impact of Screening on Breast Cancer Incidence in Kazakhstan: Results of Component Analysis.

OBJECTIVE: The study is to conduct a component analysis of the dynamics of the incidence of BC (BC) in Kazakhstan, taking into account regions. METHODS: Primary data were for registered patients with BC (ICD 10 - C50) in the whole country during the period of 2009-2018. Evaluation of changes in BC incidence in the population of Kazakhstan was performed using component analysis according to the methodological recommendations. RESULTS: The study period, 40,199 new cases of BC were recorded. The incidence rate increased from 39.5 (2009) to 49.6 in 2018 and the overall growth was 2.8 per 100,000 population of female, including due to the age structure - ∑ΔA=+2.99, due to the risk of acquiring illness - ∑ΔR=+6.82 and their combined effect - ∑ΔRA=+0.31. The component analysis revealed that the increase in the number of patients with BC was mainly due to the growth of the population (ΔP=+31.1%), changes in its age structure (ΔA=+18.0%) and changes associated with the risk of acquiring illness (ΔR=+41.0%). The increase in the number of patients in the regions of the republic is associated with the influence of demographic factors and with risk factors for getting sick, including mammographic screening. CONCLUSION: Thus, as a result of the component analysis, the role of the influence of demographic factors and the risk of acquiring illness on the formation of the number of patients and the incidence of BC was evaluated, while geographical variability was established. This research was the first epidemiological study of the dynamics of BC in the regional context by the method of component analysis in the population of Kazakhstan. The implementation of the results of this study is recommended in management of anticancer activities for BC.

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 0 0000 (95% CI=56.2-67.6) in Almaty and 61.2 0 0000 (95% CI=56.765.7) in Astana. The average age-standardized mortality was 19.2 0 0000 (95% CI=17.3-21.1) in Almaty and 19.3 0 0000 (95% CI=17.1-21.4) in Astana. The standardized incidence in the megapolises tended to increase (Tgr=+0.8% in Almaty and Tgr=+1.4% in Astana), while the mortality was decreasing (Tdec=-4.2% in Almaty and Tdec=-1.1% in Astana). According to the component analysis, the growth in the number of breast cancer cases was due to a population increase (ΔP=+130.4% in Almaty and ΔP=+93.2% in Astana), with a notable decrease of factors related to the risk of getting sick (ΔR=-27.9% in Almaty, ΔR=-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.