<![CDATA[Radiotherapy depends on functioning equipment, reliable electricity, specialised personnel, and repeated patient attendance, making service continuity vulnerable during disasters and humanitarian crises. This systematic review synthesised evidence on radiotherapy disruption, adaptive responses, and implications for Indonesia. A thematic systematic review with narrative synthesis was conducted following PRISMA 2020 and the approach described by Thomas and Harden. Five databases were searched in April 2026, supplemented by citation searching and grey literature. Methodological quality was assessed using MMAT, AMSTAR-2, AGREE-II, or narrative appraisal according to study type. Forty-nine sources were included: 41 (84%) concerned pandemics/PHEICs, four (8%) armed conflict, and four (8%) natural disasters. Five domains were identified: patient access, infrastructure/equipment, pandemic-specific disruption, preparedness/resilience, and workforce disruption. Treatment and scheduling changes, particularly for brachytherapy, emerged as a cross-cutting mechanism. Pandemic evidence suggested greater disruption in LMIC settings, although this could not be generalised to other crisis types. For Indonesia, single-LINAC dependency, geographic dispersion, and multi-hazard exposure indicate preparedness vulnerabilities. Four priorities are proposed: a national multi-hazard preparedness framework, equipment and power redundancy, selective hypofractionation, and formal inter-centre transfer pathways. Further research should prospectively evaluate these strategies in Indonesia and other LMIC settings.]]>
