Left-sided breast cancer radiotherapy with and without breath-hold: Does IMRT reduce the cardiac dose even further?

Abstract

PurposeIn radiotherapy for left-sided breast cancer, Active Breathing Control enables a decrease of cardiac and Left Anterior Descending (LAD) coronary artery dose. We compared 3D-Conformal (3D-CRT) to Intensity Modulated Radiotherapy (IMRT) treatment plans based on free-breathing (FB) and breath-hold (BH). We investigated whether IMRT enables an additional decrease of cardiac dose in radiotherapy plans with and without BH. Methods and materialsTwenty patients referred for whole breast irradiation were included. The whole breast, heart and LAD-region were contoured. Four treatment plans were generated: FB_3D-CRT; FB_IMRT; BH_3D-CRT; BH_IMRT. Several doses were obtained from Dose Volume Histograms and compared. Results were compared statistically using the Wilcoxin Signed Rank Test.For heart and LAD-region, a significant dose reduction was found in BH (p<0.01). For both BH and FB, a significant dose reduction was found using IMRT (p<0.01). By using IMRT an average reduction of 5% was noted in the LAD-region for the volume receiving 20Gy.In 5 cases, the LAD-region remained situated in the vicinity of the radiation portals even in BH. Nevertheless, with IMRT the LAD dose was reduced in these cases. ConclusionIMRT results in a significant additional decrease of dose in the heart and LAD-region in both breath-hold and free-breathing.