Deep inspiration breath-hold for breast cancer radiotherapy: a modelling study of targeted versus non-targeted strategy for clinical and operational optimisation.

Abstract

<h4>Background</h4>Deep inspiration breath-hold (DIBH) holds promise in mitigating late cardiac and pulmonary toxicities in breast cancer patients. However, DIBH increases resource demands, potentially compromising operational efficiency and access to radiotherapy (RT). The aim of this study is to compare the operational implications of a targeted RT approach based on cost-effectiveness with those of non-targeted approaches.<h4>Methods</h4>A state-transition microsimulation model was developed to assess the cost-effectiveness of DIBH versus Free Breathing (FB) in Belgian women aged 40-79 years receiving left- or right-sided RT, with or without regional nodal irradiation. Baseline cardiovascular and lung cancer risks were estimated using SCORE2 and PLCO_all2014 equations, while post-RT risks were derived using normal tissue complication probability models. A healthcare payer perspective was adopted to estimate the incremental cost-effectiveness ratio (ICER) based on quality-adjusted life years (QALYs) and direct healthcare costs. In parallel, a discrete event simulation model evaluated the operational impact of three RT strategies: (1) 100% FB, (2) 100% DIBH, and (3) targeted DIBH (selective use in cost-effective cases).<h4>Findings</h4>DIBH was cost-effective in 58.3% of patients, exhibiting more pronounced benefits in individuals with left-sided cancer, node-positive disease, smokers, those with elevated baseline CVD risk, and older age groups. Compared with not using DIBH, adopting DIBH universally led to a 21.7% (95% CI [21.2%-22.2%]) decrease in maximum throughput whereas a targeted approach (i.e., 58.3% DIBH) resulted in a 13.1% (95% CI [12.9%-14.0%]) reduction in maximum throughput.<h4>Interpretation</h4>A targeted RT approach prioritises DIBH for those deriving the most benefit, improving RT resource utilisation and supporting value-based healthcare.<h4>Funding</h4>This research was funded by the Strategic Research Programme (zwaartepunt, SRP 53, 2019-2024) 'Societal Benefit of Markerless Stereotactic Body Radiotherapy: a Statistical Support based on Quantitative Imaging' (SMARTQI of the Vrije Universiteit Brussel) and the 'Value-Based Breast Radiotherapy' research grant from Kom op tegen Kanker (KOTK_VUB/2024/13906).