Advantage of deep inspiration breath hold in left-sided breast cancer patients treated with 3D conformal radiotherapy

Purpose: To compare 3D-conformal radiotherapy (3D-CRT) treatment plans based on free-breathing (FB) and deep inspiration breath hold (DIBH) and investigated whether DIBH technique enables a decrease of cardiac left anterior descending coronary artery (LADCA) and lungs dose with respect to the FB. Methods: Twenty-three left-sided breast cancer patients referred for breast radiotherapy were included. The planning target volume (PTV) encompassed the breast and organs at risk including heart, LADCA, lungs, and contralateral breast, which were contoured in FB and DIBH CT scans. Dose to PTV was 50 Gy in 25 fractions. Two treatment plans were generated for each patient: FB-3D-CRT and DIBH-3D-CRT. Dosimetry parameters were obtained from dose volume histograms. Data were compared using the paired-sample Wilcoxon signed rank test. Results: For heart, LADCA, and left lung, a significant dose reduction was found using DIBH technique. By using DIBH, an average reduction of 25% was observed in LADCA for the volume receiving 20 Gy and of 48% considering the mean heart dose. Conclusions: The DIBH technique results in a significant decrease of dose to the heart, LADCA, and left lung compared to FB.