Effect of DIBH Coaching on Dosimetric Parameters of Heart and Lung Doses in Patients Undergoing Adjuvant Breast Radiotherapy

INTRODUCTION: Radiation exposure to the heart in women with left-sided breast cancer can lead to cardiac disease and increased mortality. Several techniques, including deep inspiration breath hold (DIBH), have been used to reduce cardiac exposure during radiotherapy. DIBH coaching prior to radiation planning can further reduce cardiac doses. This study aims to compare heart and lung dosimetric parameters between coached and non-coached patients using the DIBH technique for left-sided breast cancer treatment. METHODS: All patients with left-sided breast cancer who received adjuvant radiotherapy (RT) using the DIBH were included. The first cohort, designated as the non-coached group, received verbal guidance on the breath hold technique but did not undergo formal coaching. The second cohort involved a comprehensive coaching protocol, which began in January 2022. This protocol, led by a physician, included demonstrations and instructions for performing the DIBH technique in the clinic and encouraged patients to practice at home before and during RT to optimize cardiac protection. RESULTS: A total of 40 patients met the inclusion criteria for the study, with a mean age of 45.7 ± 8.38 years. Most patients had IDC and Stage II disease, and radiation was primarily delivered using 3DCRT with 4256 cGy in 16 fractions regimes. In terms of cardiac dose exposure, coached patients had slightly lower mean and maximum point cardiac doses, but these differences were not statistically significant. Coached patients also had a significantly lower mean V17 for left lung volume exposure compared to non-coached patients (18.3 vs. 21.6, p < 0.05). CONCLUSION: DIBH coaching and home practice prior to RT planning can further reduce cardiac and lung doses, offering a cost-effective intervention, particularly in resource-limited settings, though further controlled studies with larger sample sizes and longer follow-up are needed to assess its clinical impact.