Background <p>Cancer prehabilitation comprises structured, individualised, predominantly multimodal interventions (exercise, nutrition, psychoeducation and risk-factor modification) delivered between diagnosis and treatment initiation; however, many studies still lack a&#xa0;clear definition.</p> Objective <p>This study aims to describe the rationale, core components, entity-specific considerations and implementation options for prehabilitation in the radiotherapy setting.</p> Methods <p>We performed a&#xa0;selective review of evidence-bearing literature in cohorts receiving radiotherapy.</p> Results <p>Multimodal prehabilitation can increase functional reserve, reduce treatment interruptions and hospitalisations, potentially improve quality of life, and spare health services resources. For patients undergoing radiotherapy, entity-tailored modules (e.g., pelvic floor and swallowing training, bone health programmes, and inspiratory muscle training) and early initiation appear to be particularly relevant. Key outcome triad: complete, dose-intense and on-schedule radiotherapy delivery; toxicity; and patient-reported outcome measures (PROMs).</p> Conclusion <p>Prehabilitation in radiotherapy is feasible and clinically impactful. Standardised care pathways with systematic screening, multimodal intervention bundles, and quality-assured outcome tracking should be further evaluated and implemented.</p>