Estimating total and diagnosed global cancer incidence and stage distribution from 1990 to 2050: a simulation-based...

Cancer incidence is increasing globally, with the largest burden in low-income and middle-income countries. Workforce shortages and health system barriers contribute to substantial diagnostic delays and underdiagnosis, but estimates of undiagnosed cancer burden are lacking. The aim of this study was to estimate incidence (total and diagnosed) and stage at diagnosis in each country for 17 cancers from 1990 to 2050.

We developed the Global Cancer Workforce microsimulation model to simulate 17 cancer types (oral, nasopharynx, oesophagus, stomach, colon, rectum, anus, liver, pancreas, lung, skin melanoma, breast, cervix uteri, ovary, prostate, bladder, and brain and CNS) in 200 countries and territories from 1990 to 2050, accounting for demographic trends and health system factors, including ten specific workforce personnel types relevant to cancer diagnosis. We calibrated the incidence module to empirical data on diagnosed cancer incidence and stage distribution at diagnosis. Using the calibrated model, we estimated both total (underlying) and diagnosed crude and age-standardised incidence rates (per 100 000 population) and numbers of cancer cases for each country and region from 1990 to 2050. We also estimated the proportion of cancers diagnosed at each stage (I-IV).

Globally, among the 17 cancers included in the model, diagnosed cancer incidence was projected to increase from 13·58 million (95% uncertainty interval [UI] 12·17-14·51) cases in 2025 to 19·32 million (17·65-21·33) in 2050. Lung, breast, and prostate cancers were projected to remain the most commonly diagnosed cancers globally. The proportions of incident cancers that die undiagnosed showed large disparities by region, ranging from 0·9% (95% UI 0·6-1·3) in western Europe to 67·4% (60·1-74·2) in western Africa, with a global average of 31·5% (28·1-36·7). Globally, the proportion of cancers diagnosed at advanced stages (III-IV) was projected to decline slightly, from 45·7% (44·7-46·7) in 2025 to 44·7% (43·7-45·7) in 2050, with worse stage distributions in Africa and Asia compared with other regions.

These findings highlight the substantial and growing burden of cancers, especially in low-income and middle-income countries, where many people who develop cancer die undiagnosed. Accounting for demographic and epidemiological trends as well as health system factors, our modelling framework enables evaluation of targeted interventions to strengthen the cancer workforce and improve diagnostic pathways across diverse geographical and socioeconomic settings.

American Cancer Society and Breast Cancer Research Foundation.