What new dose distribution statistics may be included in the optimization of dose distribution in radiotherapy for post-mastectomy patients

Abstract

Introduction. The main aim of this study was to evaluate the doses delivered to heart substructures and calculate NTCP for IMRT irradiated group of left side post-mastectomy patients. Material and methods. In this retrospective study for the 30 randomly chosen breast cancer patients the mean dose, V2, V4, V10, V20 and D2% in the heart substructures were evaluated. Results. The mean heart dose was 12.3 Gy, the mean LAD dose was 28.5 Gy. The average value of the long-term cardiac mortality was 0.17%, the pericarditis 0.0%, the left ventricle perfusion defects 24.5% and the LAD toxicity was 0.2%. In the literature, for the IMRT technique for left-sided mastectomy patients, the mean heart dose ranged from 8.7–14.0 Gy and the V20 10.5–14%. The additional studies are needed to describe the cardiac toxicity. Conclusions. It necessary to contour cardiac substructures for reliable assessment the dose distribution although the mean heart dose is simplification for modern radiotherapy techniques.