Intercontinental and Regional Disparities in Cancer Burden: A Comprehensive Analysis of Trends and Projections Using 1990-2021 GBD Data with Forecasting to 2035

Abstract

Background: Understanding the intercontinental and regional cancer burden attributable to modifiable risk factors is crucial for developing effective prevention strategies. Using GBD 2021 data, this study aims to identify disparities in cancer burden, predict future trends across different continents, and inform targeted interventions.

Methods: This study utilized the GBD 2021 framework to comprehensively assess the cancer burden across four world regions, with a focus on age-standardized incidence rates (ASIR), age-standardized mortality rates (ASMR), and disability-adjusted life years (DALYs). We systematically analyzed cancer-related risk factors using associations extracted from the GBD database. Through the application of average annual percent change (AAPC) and the Bayesian age-period-cohort (BAPC) model, we forecasted the cancer burden in each region from 2022 to 2035.

Findings: In 2021, cancer incidence and mortality rates varied significantly across continents. The Americas had the highest incidence (1633·49 per 100,000) and a mortality rate of 116·097, followed by Europe with 950·248 and 132·578, respectively. Asia reported an incidence of 636·893 and mortality of 112·329, while Africa had the lowest rates at 332·175 and 98·594. Europe exhibited the highest DALYs at 3284·53 per 100,000, reflecting a substantial cancer burden. High-income regions predominantly experienced lifestyle-related cancers, such as those linked to smoking, colorectal, and breast cancers, whereas low-income areas, notably sub-Saharan Africa, faced infection-driven cancers like cervical cancer. Young females under 35 had a higher cancer burden than males, but this trend reversed after age 70, with men showing higher mortality across all age groups. Smoking remained the leading mortality risk in the Americas, Europe, and Asia, while unsafe sex was the predominant risk in Africa, aligning with high cervical cancer rates. Since 1990, high BMI and blood glucose have emerged as major cancer risk factors, influenced by rising obesity and metabolic diseases. By 2035, incidence in the Americas is projected to increase to 1779·6 per 100,000, with stable mortality at 98·97, while other regions are expected to show moderate shifts, indicating varied progress in cancer prevention and management across regions.

Interpretation: This study reveals pronounced global disparities in cancer burden, shaped by economic development, healthcare access, and lifestyle factors. High-income regions, like North America and Europe, show high incidence but lower mortality rates due to robust screening and preventive measures. Conversely, low-income regions, especially sub-Saharan Africa, experience high mortality from preventable cancers, highlighting critical healthcare gaps. Gender analysis shows women have a higher incidence due to screening, while men face higher mortality risks. Projected increases in incidence globally underscore the urgency for tailored cancer control strategies, focusing on prevention and healthcare access improvements across diverse socio-economic contexts.

Funding: This study received no funding.

Declaration of Interest: The authors declare no competing interests.

Keywords: Cancer burden, Intercontinental disparities, Global analysis, Incidence, Mortality, Risk factors, Cancer projections