Global and Regional Trends in Incidence and Mortality of Female Breast Cancer

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Global and Regional Trends in Incidence and Mortality of Female Breast Cancer and Associated Factors at National Level from 2000 to 2019

Breast cancer remains the most prevalent malignancy among women worldwide, with substantial variations in incidence and mortality across regions. A comprehensive analysis of global trends from 2000 to 2019 reveals critical insights into the evolving burden of female breast cancer (FBC), highlighting disparities linked to socioeconomic development, age-specific patterns, and modifiable risk factors.

Geographical and Socioeconomic Disparities in Breast Cancer Burden

In 2020, an estimated 2.3 million new FBC cases and 684,996 deaths were reported globally. Age-standardized incidence rates (ASIRs) and mortality rates (ASMRs) exhibited stark geographical heterogeneity. Countries with very high Human Development Index (HDI) values, such as Belgium (ASIR: 113.2/100,000) and the Netherlands (ASIR: 100.9/100,000), reported the highest incidence rates. Conversely, low-HDI regions like Gambia (ASIR: 11/100,000) and Botswana (ASMR: 2.5/100,000) showed the lowest rates. China recorded the highest absolute number of new cases (416,371) and deaths (164,959), underscoring its significant burden despite a moderate ASIR (39.1/100,000) and ASMR (8.2/100,000).

The relationship between HDI and FBC burden followed distinct patterns. ASIRs increased linearly with higher HDI, reflecting greater exposure to risk factors like delayed childbirth, reduced breastfeeding, and Westernized lifestyles in affluent nations. In contrast, ASMRs initially rose with HDI but declined in very high-HDI countries (>0.9), likely due to advanced healthcare systems, early detection programs, and improved treatment access.

Temporal Trends in Incidence and Mortality (2000–2019)

Joinpoint regression analysis of data from 60 countries revealed divergent trends over two decades. Incidence rates increased significantly in 26 countries, particularly in Latin America and Asia. Ecuador experienced the steepest rise (AAPC: 2.96%), followed by China (AAPC: 2.76%). In contrast, 22 high-HDI countries, including the United States, Iceland (AAPC: −1.60%), and Norway, showed declining incidence, attributed to reduced hormone replacement therapy (HRT) use and widespread mammography screening.

Mortality trends mirrored this divergence. Nine countries, primarily low- to middle-HDI nations like Mauritius (AAPC: 1.66%) and Guatemala, faced rising mortality. Meanwhile, 31 countries achieved significant declines, with Slovenia (−2.48%) and Iceland (−2.38%) leading reductions. Stable mortality trends were observed in China, Japan, and the Philippines, reflecting delayed benefits from emerging screening programs and healthcare improvements.

Age-Specific Patterns: Rising Burden in Younger Women

Stratification by age revealed alarming trends among women aged <40 years. Incidence increased in 21 countries, notably Ecuador (AAPC: 2.74%) and Fiji (AAPC: 2.28%), suggesting heightened susceptibility to lifestyle and reproductive risk factors in younger cohorts. Conversely, 16 countries, including Norway (−1.65%) and Kuwait (−1.63%), saw declines, possibly due to targeted prevention. Mortality rose in seven countries (e.g., Fiji: 1.65%) but fell sharply in Kuwait (−3.88%), emphasizing the role of healthcare access.

For women ≥40 years, incidence rose in 26 countries, with China (AAPC: 2.98%) and South Korea (AAPC: 2.87%) experiencing rapid growth. Mortality increased in 11 countries, including Ecuador (AAPC: 1.77%), while Slovenia (−2.46%) and Iceland (−2.38%) achieved notable reductions through early detection and treatment advances.

Ecological Analysis of Risk Factors

Multivariate linear regression identified nation-level factors significantly associated with FBC burden:

  1. Incidence Drivers:

    • High Cholesterol Prevalence: A 1% increase correlated with a 2.2-unit rise in ASIR (P<0.001).
    • Health Expenditure: Higher spending linked to elevated ASIRs (β=1.61, P=0.032), reflecting detection bias in high-income settings.
    • Socioeconomic Factors: Urbanization and Westernized diets likely contributed to rising trends in transitioning economies.

  2. Mortality Determinants:

    • Obesity: A 1% increase in obesity prevalence raised ASMR by 0.35 units (P=0.020).
    • Universal Health Coverage (UHC): Weak UHC systems correlated with higher mortality (β=−0.31, P=0.045), underscoring the importance of equitable healthcare access.

Implications for Prevention and Control

The study highlights three critical challenges:

  1. Rising Burden in Developing Countries: Rapid urbanization, lifestyle changes, and aging populations are driving FBC incidence in low- to middle-HDI nations. Countries like China and Ecuador require tailored screening programs and public health campaigns targeting modifiable risks (e.g., obesity, physical inactivity).
  2. Early-Onset Breast Cancer: Increasing incidence among women <40 years demands research into etiology (e.g., genetic predispositions, environmental toxins) and age-specific screening protocols.
  3. Healthcare Inequities: Mortality reductions in high-HDI countries contrast with stagnating or rising rates in regions with limited resources. Scaling up mammography access, chemotherapy availability, and palliative care is essential.

Conclusion

Global FBC trends from 2000 to 2019 reveal a dual narrative: progress in high-income nations through prevention and treatment, contrasted with escalating burdens in developing regions. Addressing this disparity requires multisectoral strategies integrating primary prevention (e.g., obesity control, alcohol regulation), early detection programs, and investments in healthcare infrastructure. Prioritizing universal health coverage and targeted interventions for high-risk populations will be pivotal in reducing the global FBC burden.

doi.org/10.1097/CM9.0000000000001814

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