Dosimetric Efficacy of Voluntary Deep Inspiration Breath-Hold in the Radiotherapy of Left Breast Cancer Patients Using the UK START Trial

Abstract

Introduction: Deep inspiration breath-hold (DIBH) technique is widely administered to left breast cancer (LBC) patients to reduce the radiation dose to the cardiopulmonary structures. The UK standardization of breast cancer radiotherapy (UK START) dose prescription was found comparable to the conventional schedule. The current study compared voluntary DIBH and free-breathing (FB) methods in the cardiopulmonary radiation doses of LBC patients with supraclavicular irradiation treated with the UK START trial. Materials and Methods: A computed tomography (CT) scan was acquired for a group of 50 LBC patients in DIBH and FB and a radiotherapy plan was created on each scan. The dose-volume histogram (DVH) parameters of the heart and lung were analyzed against their relevant first clinical acceptance criteria using one-sample t-test. Additionally, we assessed the correlation between the ipsilateral lung volume expansion and the cardiopulmonary dosimetric benefits. Results: The DIBH technique significantly reduced the cardiopulmonary doses compared with the FB method (p < 0.001). Furthermore, the mean difference between the mean heart dose (MHD) and its first acceptance criterion was -62.6 cGy (p < 0.001), and the volume of the heart and lung received at least 16 Gy (Heart V16Gy and lung V16Gy, respectively) was lower than their first acceptance criteria by -0.63% and -2.18% (p < 0.001), respectively. In contrast, the first acceptance criteria of the cardiopulmonary dosimetric parameters were not accomplished with the FB method. In addition, the difference in MHD and heart V20Gy between DIBH and FB plans showed a moderate correlation with ipsilateral lung volume expansion (r = 0.51 and 0.5, respectively). Conclusion: The DIBH technique should be served to all locally advanced LBC patients, and the ipsilateral lung volume expansion could be a predictor for the cardiac-sparing radiotherapy in LBC.