A Six-year Experience of Using Moderate Deep Inspiration Breath-Hold for Patients With Early-Stage Breast Cancer and Dosimetric Comparison

Abstract

We present our six-year experience of using moderate deep inspiration breath-hold (mDIBH) with an active breathing control (ABC) device for patients with early-stage breast cancer and dosimetric comparison to evaluate the benefit of mDIBH on the heart, lung, and liver. We retrospectively reviewed all patients with newly diagnosed early, node-negative breast cancer treated between November 2010 and October 2016. Among the 312 patients included in this study, 94 patients were treated with mDIBH and 218 patients were treated with free breathing. Dosimetric analysis was performed to compare dose distribution in the heart, lung, and liver between the two treatment groups. All planning and dosimetric evaluations were performed on the treatment planning system. The calculated DVH was compared between the non-ABC and ABC groups. The chi-square test was used to compare the distribution of stage and tumor site between the two groups. The independent samples t-test was used to compare the remaining parameters between the two groups. Analysis was performed using SPSS v.19. There was no significant difference in the distribution of stage (p=0.130), tumor site (p=0.068), age (p=0.065), volume of CTV (p=0.119), and volume of heart (p=0.851) between the non-ABC and ABC groups. For all 312 patients, there was a significantly lower ipsilateral lung V5 (p<0.001), ipsilateral lung V10 (p<0.001), ipsilateral lung V20 (p<0.001), mean ipsilateral lung dose (p<0.001), whole lung V5 (p<0.001), whole lung V10 (p<0.001), whole lung V20 (p<0.001), mean whole lung dose (p<0.001), heart V10 (p<0.001), heart V30 (<0.001), heart V40 (<0.001), and mean heart dose (<0.001) in the ABC group. For 158 patients with a left-sided breast tumor, significantly lower ipsilateral lung V5 (p=0.004), ipsilateral lung V10 (p<0.001), ipsilateral lung V20 (p<0.001), mean ipsilateral lung dose (p<0.001), heart V10 (p<0.001), heart V30 (p<0.001), heart V40 (p<0.001), and mean heart dose (p<0.001) were observed in the ABC group. For 154 patients with a right-sided breast tumor, significantly lower ipsilateral lung V5 (p=0.006), ipsilateral lung V10 (p<0.001), ipsilateral lung V20 (p<0.001), mean ipsilateral lung dose (p<0.001), heart V10 (p<0.001), heart V30 (p=0.012), heart V40 (p=0.046), mean heart dose (p<0.001), liver V30(p<0.001), and mean liver dose (p<0.001) were observed in the ABC group. For early-stage breast cancer patients, mDIBH reduces not only the heart dose but also the lung and liver doses. Our study showed that mDIBH can significantly reduce the heart and lung dose for left-sided breast cancer patients and also reduce the liver, lung, and heart dose for right-sided breast cancer patients. The routine integration of mDIBH using an ABC device may decrease radiation-induced toxicity in the heart, lung, and liver.