Evaluation of DIBH and VMAT in Hypofractionated Radiotherapy for Left-sided Breast Cancers After Breast-conserving Surgery: a Planning Study

Abstract

Background This paper aims to compare dosimetric parameters of the organs at risk (OARs) among three different radiotherapy (RT) modalities in left breast cancer patients after breast-conserving surgery (BCS). Methods Eleven patients with left breast cancer after BCS were enrolled and underwent CT simulation in the free breathing (FB) and deep inspiration breath hold (DIBH) position. Three-dimensional radiotherapy (3DCRT) and volumetric modulated arc therapy (VMAT) plans were generated for each patient in the DIBH position. A 3DCRT plan was also created in the FB position. Dose-volume histogram (DVH) was used to analyze each evaluation index of OARs. The principal outcome was heart dose, left anterior descending coronary artery (LADCA) dose and left lung dose.Results For the 3D-CRT plans, significant dose reductions were demonstrated in all evaluation parameters to heart, LADCA and left lung dose in the DIBH position compared with the FB position (p < 0.05). In DIBH position, significant dose reductions were founded in heart and LADCA in VMAT plan compared to 3DCRT plan (p < 0.05). There were no significant differences between 3DCRT and VMAT plan for the left lung dose in DIBH position.Conclusion DIBH and VMAT could reduce dosimetric parameters of the OARs in left breast cancer patients after BCS. RT plans for left breast cancer after BCS can be optimized by DIBH and VMAT techniques to minimize radiation-induced toxicity