A decade of radiotherapy: Clinical evolution, technological innovation, and the challenge of cardiotoxicity

Radiotherapy transformed in 2015–2025, moving from incremental change to biologically informed, image-guided and increasingly automated care. This narrative review, informed by a comprehensive literature search of major databases (2015–2025), synthesises advances across clinical practice, technology, and translational science, with particular attention to radiation-induced cardiotoxicity as a key survivorship challenge. Randomised evidence established hypofractionation and stereotactic body radiotherapy as standards in selected breast, prostate and oligometastatic settings, improving efficiency without compromising control. Technological frontiers include MR-guided online adaptive radiotherapy for real-time plan modification, global expansion of proton therapy for paediatric indications and some adults, emerging biologically-guided radiotherapy (BgRT) platforms, expanding applications of radiopharmaceutical therapy (RPT), and early human feasibility of ultra-high dose-rate FLASH that may widen the therapeutic window. Artificial intelligence streamlines auto-segmentation, planning and quality assurance, while radiogenomics, radiomics and immuno-radiotherapy combinations advance personalisation. Amid these gains, late cardiovascular effects demand urgent focus: radiation-induced cardiotoxicity spans coronary, myocardial, valvular and conduction injury, with risk linked to dose-volume exposure and systemic co-therapies. Mitigation integrates deep-inspiration breath-hold, motion management, cardiac substructure contouring, proton techniques and biomarker-informed risk stratification. Persistent global access disparities, workforce shortages, and cost-effectiveness challenges highlight the need for pragmatic adoption of efficient regimens, equitable infrastructure investment, and supportive policy frameworks including AI-enabled remote planning and cloud-based quality assurance. This review synthesises advances, appraises cardiotoxicity evidence and countermeasures, and prioritises: integrate multi-omic biomarkers with adaptive, AI-enabled delivery; translate FLASH rigorously; build long-term cardio-oncology data; and implement policies extending modern radiotherapy beyond high-income settings. Radiotherapy is set to become more precise, personalised and equitable.