Cardiac & Lung Dose Evaluation with Deep-Inspiratory Breath Hold Technique vs Free breathing of Radiotherapy for Left-Sided Breast Cancer.
Authors: Col Dr. S M Rokonuzzaman
Institution: Head of Department, Department of Radiation Oncology, Combined Military Hospital, Dhaka.
Introduction
Left-sided breast cancer radiotherapy in Bangladesh, a resource-limited setting, necessitates optimising treatment strategies to minimise cardiac toxicity while maintaining efficacy. This study explores the potential of Deep Inspiratory Breath Hold (DIBH) for reducing cardiac dose in this patient population.
Methods
This retrospective study at Combined Military Hospital & Square Hospitals Ltd., Dhaka, from March 2019 to March 2025, examined 350 patients with left-sided breast cancer. It compared cardiac and lung doses using DIBH and free-breathing techniques in Intensity Modulated Radiotherapy (IMRT) and three-dimensional conformal radiotherapy (3DCRT) plans. The study included patients aged 18-70 with invasive ductal carcinoma who could hold their breath for at least 30 seconds, excluding those with low performance or incomplete treatment. Data were analysed with SPSS version 29, focusing on optimising treatment accuracy and minimising cardiac doses.
Results
In a study of three hundred fifty female patients with left-sided breast cancer, 95.0% underwent radiotherapy using the DIBH technique, primarily with Intensity Modulated Radiotherapy (IMRT, 60.0%) to enhance cardiac safety. The majority, aged 30-49 (63.3%), had received previous surgery and chemotherapy (96.7%). Treatments were standardised with supine positioning using a breast board (98.3%). In this study, the mean heart dose (Dmean) was 5.23 Gy with the free-breathing technique and 3.2 Gy with the DIBH technique, representing a 56% reduction in mean heart dose with DIBH. The mean lung dose decreased from 16.5 Gy in the free-breathing technique to 10.8 Gy with DIBH, indicating an overall 34% reduction in lung dose with the DIBH technique. A positive correlation was observed between the heart–anterior chest wall distance and the mean heart dose in both techniques. The heart–anterior chest wall distance increased from 0.461 cm during free breathing to 0.835 cm with DIBH, reflecting improved cardiac sparing with the DIBH technique.
Conclusion
This study validates the effectiveness of the deep inspirational breath-hold technique in reducing cardiac exposure during left-sided breast cancer radiotherapy. By integrating DIBH with IMRT and 3DCRT, we observed significant reductions in cardiac doses without compromising treatment accuracy. The results support wider use of DIBH, particularly in settings with limited resources, to enhance safety and efficacy in cancer treatment.