Post Mastectomy Chestwall Irradiation of Left Sided Breast Cancer with Single Energy Electron Beam Vs Three Dimensional Conformal Radiotherapy with Photons – Analysis of Dosimetric Parameters.

Abstract

The Post mastectomy chestwall radiation is routinely delivered using tangential photon fields. However for left sided tumors underlying heart and left lung form major organs at risk and this report studies the use ofsingle electron beam radiotherapy in these patients. To compare mean left lung dose, percentage volume of left lung receiving dose more than 20Gy(V20Gy), mean heart dose, percentage volume of heart receiving dose more than 25Gy(V25Gy) and 45Gy(V45Gy), percentage volume of planned target volume(PTV) receiving more than 95% of prescribed dose(V95%). There was significant difference in favour of electron- beam plans for mean lungdose (p=0.001), V20Gy of left lung(p=0.001) and V45Gy of heart (p=0.017) . There was no significant difference in mean heart dose (p=0.624) and V25 Gy of heart (0.622). The difference in percentage volume of PTV receiving more than 95% of prescribed dose (p=0.077) showed trend towards