TROG 14.04 HART: Deep Inhalation Breath Hold for reduction of cardiac toxicity in patients with left-sided breast cancer undergoing radiotherapy, HART (Heart Avoiding Radiation Therapy)

The purpose of the trial is to demonstrate the feasibility to evaluate Deep Inhalation Breath Hold (DIBH) countrywide as demonstrated in patient compliance and reproducibility of set-up. The trial is a two-arm study assessing the feasibility of DIBH during Radiotherapy treatment: the intervention group corresponds to left-sided breast cancer patients whereas the control group corresponds to right sided breast cancer patients. Left sided breast cancer patients who do not proceed to treatment with DIBH will be included in the assessment. A control group is included to compare the reproducibility of set-up between participants treated with/without DIBH and compare resource requirements. Patients will undergo DIBH (provided they are able to hold their breath in a reproducible and consistent manner for a long enough period, which is approximately 10 to 15 seconds). Participants with left-sided breast cancer will undergo breathing training if applicable. There is no prescribed breathing training for participating centres as we would like to capture clinical practice. Breathing training will also depend on the equipment used to guide DIBH. The type of breathing training that is provided by the site will be captured prior to the commencement of the trial. Most centres would provide training and according to informal discussions, this is between 20min and one hour. The training is most likely performed by radiation therapists who also oversee and conduct the planning CT scans for the patient. RTs are a registered profession. It is also common that patients undergo a ‘practice’ session prior to the CT scan where they take breaths under observation in the same way as during treatment but without either imaging or treatment delivery. When performing the DIBH, patients are asked to take a deep breath prior to radiation delivery. This is likely to move the heart away from the high dose region aimed at breast tissue (or chest wall) thereby reducing dose to the heart. Patients will perform DIBH at every radiation delivered over the five weeks. Each participant will complete and anxiety assessment before receiving standard of care radiotherapy treatment as per their institution's guidelines. All participants will have daily electronic portal imaging (EPI) taken during the first week of treatment and then weekly EPI for 5 weeks. During the 3rd week of radiotherapy treatment, the participants with left-sided breast cancer will complete another anxiety assessment. As part of the trial, patients will have two planning CT scans: Free breathing and DIBH. The scheduling of the two scans is left to department practice. Patients in the control group will only have the standard CT scan used for treatment planning. Patient follow-up will be as per institution's practice.