Recently, there is growing interest in the application of three-dimensional (3D) printed bolus to radiotherapy.At present, the researches on the application of 3D-printed bolus in breast cancer are mainly focused on air gap between skin and bolus or electron beam conformal therapy [7,15], there are no clinical experience with customized 3D-printed bolus for volumetric modulated arc therapy (VMAT) in daily practice has been published up to now. We aim to evaluate dosimetry and application of 3D-printed bolus for the post-mastectomy radiotherapy (PMRT) with Volumetric modulated arc therapy (VMAT). Seventy five patients with breast cancer receiving radiotherapy following post-mastectomy in our department were randomly selected in this study. The accuracy of fit of the 3D-Printed bolus to the chest wall was improved significantly relative to conventional bolus.This study demonstrates customized 3D-printed bolus in post-mastectomy radiation therapy improves fit of the bolus compared to conventional bolus. Furthermore, VMAT based on 3D-printed bolus significantly improves the chest wall target coverage and the conformity of plan, and reduces the dose of ipsilateral lung and heart, compared to conventional bolus.

Inclusion Criteria:

• breast cancer patients with post-mastectomy treatment

Exclusion Criteria:

• NA