ESTRO 2024 - Abstract Book

S3974

Physics - Inter-fraction motion management and offline adaptive radiotherapy

ESTRO 2024

186

Digital Poster

Prospective study on impact of CBCT on heart dose variation in breath hold breast RT(NCT03459898)

Adrian Wai Chan, Anh Hoang, Hanbo Chen, Merrylee McGuffin, Danny Vesprini, Matt Wronski, Irene Karam

Odette Cancer Centre, Sunnybrook Health Sciences Centre, University of Toronto, Radiation Oncology, Toronto, Canada

Purpose/Objective:

Higher mean heart dose (MHD) in breast cancer radiotherapy (RT) is associated with an increased risk of ischaemic heart disease. Though breath hold techniques can reduce the heart dose compared with free breathing, there can still be interfractional variation of heart position and dose, which may also contribute to the increased risk of RT induced cardiac damage. It is not known whether the extent of such interfractional variation may differ according to the breath hold technique and whether it can be reduced by cone beam computed tomography (CBCT) imaging. The aim of this prospective study is to assess whether CBCT can reduce interfractional variation of MHD among breath hold RT techniques using voluntary deep inspiration breath hold (vDIBH), active breathing control (ABC) and surface guided radiotherapy (SGRT).

Material/Methods:

This is a single-centre, prospective, non-randomized and open-labelled trial comparing breath hold techniques in breast cancer RT. Following curative-intent surgery for breast cancers, patients with left sided breast cancers who required tangential RT using field-in-field technique were assigned to one of three sequential cohorts: breath hold techniques with vDIBH using surface skin marks, ABC using the Elekta system and SGRT using AlignRT® system (see Figure 1).