Epidemiology of Breast Cancer in Kazakhstan (2015–2023)

Abstract

Background: Breast cancer is the most frequently diagnosed malignancy among women worldwide, with approximately 2.3 million new cases annually (Kim et al., 2025). In Kazakhstan, it ranks first among female cancers and remains the leading cause of cancer-related mortality. Despite increasing incidence, declining mortality suggests improvements in early detection and treatment following the implementation of national screening programs. Aim: This study aimed to assess epidemiological trends, clinical characteristics and survival predictors of breast cancer in Kazakhstan from 2015 to 2023 using a nationwide registry-based cohort. Results: A total of 51,229 patients were included in the analysis, where 35,882 were alive and 15,347 people were diseased according to registry. Most patients were aged 50 years and older, accounting for approximately eighty percent of the cohort. Among 88 percent of alive patients were at early stages (Stage I and II) of breast cancer, which indicated a shift toward earlier detection. The most common tumor location was the upper outer quadrant (45.9%). The highest number of cases was reported in Karaganda region, Almaty and Astana cities. Regarding treatment, about 57% of survivors underwent surgical procedures, while 46.5% received chemotherapy. Survival analysis showed that mortality was strongly associated with older age and advanced stage at diagnosis. Multivariable Cox regression identified stage, age and metastases as significant predictors of mortality. Conclusion: The findings suggest a shift toward earlier detection of breast cancer in Kazakhstan, which is likely reflects the effect of national breast cancer screening program. However, regional disparities remain, with rural population experiences less favorable outcomes. It is necessary to improve access to timely diagnosis and comprehensive care. Further development of integrated cancer registries, including clinical and molecular type of breast cancer data, may enhance future cancer prevention strategies.