Abstract
INTRODUCTION: Many patients struggle to sustain Deep Inspiration Breath Hold (DIBH) during breast cancer (BC) radiation therapy (RT). Identifying barriers to tolerance can guide targeted interventions and optimise departmental resources, particularly in rural settings. We aimed to: (i) identify factors affecting DIBH tolerance; (ii) develop a structured screening program; and (iii) evaluate its effectiveness. METHODS: We retrospectively reviewed the medical records of all BC patients offered DIBH between 2020-2024 at the North Coast Cancer Institute (NCCI), Lismore, NSW. Patient characteristics and documented reasons for DIBH intolerance informed the development of a radiation therapist-led screening tool introduced in 2023. The program involved mock treatment positioning and a brief functional assessment of DIBH capacity based on pain, physical limitations, respiratory capacity, psychological barriers, and chemotherapy-related effects, with coaching or referral as required. The screening program classified patients as: able without intervention; able with intervention; or unable despite intervention. We summarised findings using descriptive statistics. RESULTS: DIBH was offered to 214 patients (median age 64 years) with 75 (35%) unable to tolerate the technique. Reasons for intolerance included respiratory-related (20%), physical/pain limitations (7%), psychological factors (6%), and chemotherapy-related effects (2%). Among the 139 who completed DIBH, reported challenges included pain (23%), anxiety (4%), respiratory issues (3.5%), and isolated cases of chemotherapy-related effects or language barriers. Screening demonstrated 96% concordance with CT simulation outcomes (50/52 patients), with 21% requiring intervention to enable DIBH. DISCUSSION: The screening program accurately identified DIBH suitability, facilitated early intervention, and supported person-centred, resource-conscious decision-making. Routine implementation is recommended, particularly in resource-limited settings.