Global cancer statistics among older adults in 2024 with projections to 2050: a multi-source population-based analysis

BACKGROUND: Cancer is the second leading cause of death worldwide and disproportionately affects older adults. As population ageing accelerates, the global cancer burden among older adults continues to increase. This study systematically evaluated the latest global cancer burden and its epidemiological characteristics among older adults. METHODS: Data on the incidence and mortality of 33 malignancies, excluding non-melanoma skin cancer, among adults aged 65 + were extracted from the Global Cancer Observatory (GLOBOCAN) 2024 and Global Burden of Disease Study (GBD) 2023 databases and stratified by age, sex, region, and Human Development Index (HDI). Age-standardized incidence and mortality rates (ASIR and ASMR) were calculated. Annual percentage changes (APC) were used to characterize temporal trends. Decomposition analysis was performed to quantify the contributions of population growth, population aging, and epidemiological changes. Demographic projection methods and generalized additive model (GAM) were applied to forecast the cancer burden through 2050. RESULTS: In 2024, there were 9,966,392 new cancer cases and 6,001,290 cancer deaths among older adults worldwide, accounting for 51.11% and 61.84%, respectively, of all-age totals. Lung, colorectal, stomach, liver, and prostate cancers were leading causes of death. Incidence and mortality were higher in men and increased with age. The Western Pacific Region had the largest burden, whereas Europe Region had the highest ASIR. ASIR correlated positively with HDI (rs = 0.771), while mortality-to-incidence ratio (MIR) correlated negatively (rs = -0.825). From 2000 to 2023, ASIR and ASMR declined, although burden increased, primarily driven by population growth; pancreatic cancer exhibited the most rapid increase. Tobacco use remained the leading risk factor for mortality, while metabolic risks rose in importance. Under a demographic scenario assuming constant 2024 age-specific rates and changes only in population size and age structure, new cancer cases and deaths among older adults are projected to reach approximately 19.8 million and 12.5 million by 2050, roughly double the 2024 figures, with the largest increase in the Eastern Mediterranean region. CONCLUSION: Cancer burden in older adults is substantial, varying by sex, age, region, and development level. Precision prevention and control are urgently needed, particularly in low- and middle-income regions. REGISTRY AND THE REGISTRATION NO. OF THE STUDY/TRIAL: N/A.