Learning to breathe for radiation therapy: a scoping review of deep inspiration breath-hold training

: Deep inspiration breath-hold (DIBH) is widely used in radiation therapy (RT) to reduce radiation exposure to organs at risk, particularly during breast cancer treatment. Successful implementation of DIBH relies on high levels of patient compliance and breath-hold reproducibility. Structured patient training has been proposed as a key component to optimise DIBH performance; however, evidence regarding training modalities and their clinical impact remains fragmented. This scoping review aims to map the available evidence on DIBH training strategies and their outcomes in RT. Literature searches were conducted using PubMed, Embase, Scopus, and Web of Science from inception to 9 October 2025. Twelve studies fulfilled the selection criteria. Most investigations focused on breast cancer patients (n=10; 83%), with limited evidence available for other anatomical sites. Most studies were comparative, evaluating trained versus untrained patients or different training approaches. Across studies, DIBH training was associated with multidimensional benefits, including dosimetric improvements, enhanced breath-hold reproducibility, and reductions in simulation, set-up, and treatment times. Additionally, patient-reported outcomes indicated high satisfaction and increased confidence following training. Considerable heterogeneity was observed in both the endpoints assessed and the training approaches and delivery modalities. Nevertheless, most studies supported the inclusion of home-based practice following initial coaching. Available evidence suggests that structured DIBH training provides clinically relevant benefits across the RT pathway. Current evidence is limited by small sample sizes and predominantly single-centre designs, highlighting the need for standardized training methodologies and outcome measures to enable more robust comparisons across studies.