Three-Year Outcome Evaluation of Deep Inspiration Breath Hold Technique in Post–Radiation Therapy Patients After Left-Sided Breast-Conserving Surgery by Echocardiography With Quantitative Tissue Velocity Imaging

Abstract

This study aims to evaluate the benefits of deep inspiration breath hold (DIBH) technique over free breathing (FB) by quantitative tissue velocity imaging(QTVI) in patients with left-sided breast cancer. Between 2012 and 2014, 68 patients with T1–2N0 breast cancer (BC) received whole breast radiotherapy (RT) after breast-conserving surgery (BCS) in our hospital. Patients treated with adjuvant chemotherapy were excluded. 30 patients treated with FB（A group and 38 patients took the DIBH technique (B group) using Varian real-time position management (RPM) system. The prescribed dose was 46 Gy in 23 fractions for the whole breast and 14Gy in 7 fractions for resection cavity. Each patient received the QTVI in the initial day of RT and 3 years after RT. The following data are acquired: The diameter of left atrial and late diastolic left ventricle (LV), the thickness of interventricular septum and LV posterior wall, LV ejection fraction, the peak velocity of mitral inflow (E/A). Regional velocity profiles of 6 walls of LV. The peak velocity of systolic (Vs), early diastolic velocity (Ea), late diastolic velocity(Aa) and the ratio of Ea and Aa(Ea/Aa). Parameters of interest about RT plan, cardiac V5, mean LAD dose, maximum LAD dose, and mean heart dose were calculated and analyzed. All enrolled patients completed the study. The cardiac V5, mean LAD dose, maximum LAD dose, and mean heart dose in RT plan of A group were always significant lower than those of B group (P<0.05). The differences of all parameters about QTVI between A and B group were not significant before radiotherapy. Compared with A group after radiotherapy, E/A、Vs、Ea/Aa were significantly reduced in B group after radiotherapy (P<0.05). This study shows that there is markedly reduced cardiac exposure in patients with DIBH as compared to FB. At the end of 3rd year, radioactive heart damage was significantly less in patients using DIBH technique than FB. The DIBH is a clinically useful heart protection for radiation therapy of left-sided breast cancer after BCS. Keyword: DIBH; radioactive heart damage; echocardiography; QTVI.