Dosimetric Comparison of Different Fractionated 3D Radiotherapy Regimens for Breast Conservation

Background and Objectives This study compared conventional dose fractionation and hypofractionation in breast cancer radiotherapy to optimize treatment planning using different physical indices Subjects and Methods In this retrospective study, the treatment plans of 30 patients eligible for radiotherapy for left-sided breast cancer were investigated. Patients were treated with a conventional dose- interval regimen and three hypofractionated regimens. Dosimetry indexes such as the homogeneity index, conformity index, and mean dose to the left breast, lung, and heart were extracted from the dose-volume histogram and compared with each other to study the four different treatment regimens. Results According to the data obtained, the mean dose to the left breast (PTV), heart and ipsilateral lung was significantly reduced in hypofractionation methods compared to conventional regimen. The homogeneity and the conformity index values showed no significant difference in any of the treatment regimens. The dose received showed no difference in lung volume. For heart, the volume of 38 and 43% of the prescribed dose were significantly higher in the conventional method than in the three hypofractionation regimens. Conclusion Hypofraction treatment regimens with fewer treatment fraction and a dose per fraction greater than 2Gy compared to conventional dose fractionation led to a dose reduction for the heart and the same side of the lung.