2933 - Global Greenhouse Gas Emissions from External Beam Radiotherapy: Country-Level Projections to 2050
Presenter(s)
H. Zhu1, I. Meattini2, L. Zhang3, A. Levy4, M. Cao5, S. Stanway6, F. Meng3, E. Rivin del Campo7, K. L. M. Chua8, Z. Zhang9, and M. Abdel-Wahab10; 1Department of Radiation Oncology, Fudan University Shanghai Cancer Center, Fudan University, Shanghai, China, Shanghai, China, 2Department of Experimental and Clinical Biomedical Sciences “M. Serio”, University of Florence, Florence, Italy, 3Beijing Normal University, Beijing, China, 4Institut Gustave Roussy, Villejuif, France, 5Department of Radiation Oncology, University of California San Francisco, San Francisco, CA, 6Royal Marsden Hospital, London, United Kingdom, 7Hopital Tenon, Paris, France, 8National Cancer Centre Singapore, Singapore, Singapore, 9Department of Radiation Oncology, Fudan University Shanghai Cancer Center; Department of Oncology, Shanghai Medical College, Fudan University; Shanghai Clinical Research Center for Radiation Oncology; Shanghai Key Laboratory of Radiation Oncology, Shanghai, China, 10International Atomic Energy Agency, Vienna, Austria
Purpose/Objective(s): Radiotherapy is essential for cancer control, but scaling access must occur alongside decarbonisation of health systems. The global and country-level greenhouse gas emissions implications of external beam radiotherapy (EBRT) scale-up to 2050 remain uncertain.
Materials/Methods: We conducted a country-level, scenario-based modelling study across 181 countries to estimate EBRT-associated greenhouse gas emissions in 2022 and project emissions to 2050. We evaluated radiotherapy scale-up under utilisation envelopes (50% and 64%) and fractionation assumptions, including uniform schedules (25, 15, and 5 fractions per course) and prespecified income-stratified hypofractionation adoption pathways (Moderate and Ambitious) with income-group–specific fractionation mixes and derived mean fractions. We additionally used country-specific utilisation rates as an access-constrained sensitivity scenario.
Results: Across all scenarios, global EBRT-associated emissions increased from 2022 to 2050. Under conventional 25-fraction delivery, emissions rose from 43.02 to 67.94 MtCO2e under the 50% utilisation benchmark and from 55.06 to 86.96 MtCO2e under the 64% benchmark. Shorter-course delivery substantially reduced projected totals (15 fractions: 25.81 to 40.76 MtCO2e under 50% utilisation and 33.04 to 52.18 MtCO2e under 64% utilisation; 5 fractions: 8.60 to 13.59 MtCO2e and 11.01 to 17.39 MtCO2e, respectively). Using realised country-level utilisation yielded a similar increase under 25 fractions (41.62 to 65.89 MtCO2e). Relative to 25 fractions, hypofractionation reduced emissions by approximately 40% (15 fractions) and 80% (5 fractions) across utilisation benchmarks. Emissions growth shifted towards middle-income settings: under the 50% utilisation benchmark with 25 fractions, the high-income share declined from 42.9% in 2022 to 36.5% in 2050, while the lower-middle-income share increased from 15.3% to 19.5%. Emissions remained highly concentrated, with the top 10 emitting countries accounting for 64.5% of global emissions in 2022 and 60.6% in 2050. Prespecified income-stratified adoption of hypofractionation materially reduced these totals without restricting scale-up. Compared with a uniform 25-fraction baseline, the Moderate pathway reduced global emissions by 23.3% in 2022 (43.02 to 33.01 MtCO2e) and 21.9% in 2050 (67.94 to 53.07 MtCO2e), while the Ambitious pathway achieved larger reductions of 36.5% and 34.7%, respectively.
Conclusion: Global EBRT-associated emissions are projected to rise substantially by 2050 across plausible scale-up scenarios. Implementing clinically appropriate hypofractionation and efficiency measures during radiotherapy expansion offers a pragmatic pathway to reduce avoidable emissions without constraining equitable access.