West Asia Organization for Cancer Prevention (WAOCP), APOCP's West Asia Chapter. Asian Pacific Journal of Cancer Prevention 1513-7368 22 12 2021 12 01 Hypofractionated Hybrid Radiotherapy Techniques for Synchronous Bilateral Breast Cancer 3933 3939 89897 10.31557/APJCP.2021.22.12.3933 EN Karunakaran Balaji School of Advanced Sciences, Vellore Institute of Technology, Vellore, India. Department of Radiation Oncology, Gleneagles Global Hospitals, Chennai, India. 0000-0002-1606-8769 Velayudham Ramasubramanian School of Advanced Sciences, Vellore Institute of Technology, Vellore, India. 0000-0002-4834-1141 Journal Article 2021 09 01 Objective: This study intends at a dosimetric comparison of four different hybrid plans which is a combination of different radiation therapy techniques, for synchronous bilateral breast cancer (SBBC) irradiation using a hypofractionated dose regimen. Methods: Four different hybrid techniques: 3DCRT+IMRT, 3DCRT+VMAT, IMRT+VMAT, and VMAT+IMRT were planned using computed tomography (CT) images of fifteen SBBC patients.  All hybrid plans were generated using a hypofractionated dose prescription of 40.5 Gy in 15 fractions. 70% of the dose was planned with a base-dose component and the remaining 30% of the dose was planned with a hybrid component. The plans were evaluated based on the PTV and organs at risk (OARs) dosimetric parameter results and computed a plan quality score for each plan. Results: The results for PTV parameters have shown that the 3DCRT+VMAT and 3DCRT+IMRT plans were better than other plans. The 3DCRT±IMRT plan was provided better results for OARs, while IMRT±VMAT and VMAT+IMRT plans were increased the low dose volumes to the heart and lungs. The 3DCRT+VMAT plan was required less monitor units and treatment time compared to other plans. Conclusion: The overall plan quality score that integrated the dosimetric parameters of PTV and OARs indicated that the 3DCRT+VMAT hybrid plan is superior for SBBC treatment. https://journal.waocp.org/article_89897_0f9ce62f5ee76879492a085a423344f0.pdf