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

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.

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.

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).

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.