Stage-adjusted forecasting of radiotherapy demand and outcome benefits across income groups: estimating survival and local control gains by 2050

Background: Radiotherapy is a vital component of cancer care, yet access is limited. Global estimates often overlook cancer stage variability across countries with different income levels. This study assesses the supply–demand gap for megavoltage radiotherapy machines (MVMs) from 2012 to 2022 and projects the survival and local control benefits achievable by meeting optimal radiotherapy needs by 2050. Methods: Global cancer data were from GLOBOCAN 2022. A validated, stage-adjusted radiotherapy utilisation model was adapted using available cancer stage data from LMICs for each geographical region. Population-based models estimating local control and survival benefit from radiotherapy were also stage-adjusted. The overall shortfall was calculated as patients not receiving treatment due to limited MVM availability. Corresponding outcome gaps were estimated by multiplying shortfall cases by their respective benefit percentages. Results: Radiotherapy demand increased by 2.4 million cases from 2012 to 2022. Optimising access would yield survival benefits for >860,000 people annually and improved local control for 3.5 million cases annually. Lower-middle-income countries are estimated to derive the highest population-based benefits in local control (10.65 %) and survival (4.94 %). The number of patients missing radiotherapy is projected to reach 7.9 million by 2050, creating a global local control gap of 1.2 million and a survival gap of 500,000 cases per year. Conclusion: This study highlights the urgent need for enhanced policies and expanded infrastructure to address radiotherapy disparities, particularly in LMICs, to improve local control and survival outcomes.