Abstract P3-12-06: Active breathing control in the management of left-sided breast cancer with irradiation: A dosimetric analysis of cardiac and lung dose

Abstract

Abstract Purpose: Deep inspiratory breath hold (DIBH) is a technique that has been increasingly utilized over the past several years for the purpose of reducing the radiation dose received by the heart and ipsilateral lung during radiotherapy (RT) for breast cancer. The purpose of this study was to provide a comparative analysis of cardiac and lung dose in patients treated with and without moderate DIBH with an active breathing control (ABC) device during RT for left-sided breast cancer at a community radiation oncology center. Methods: From June 2013 to December 2014, 83 patients with stages 0-III left-sided breast cancer were treated with RT. Of these, 45 patients underwent CT simulation with an ABC device and the remaining 38 patients underwent standard free-breathing CT simulation for RT planning. Twenty-eight patients in the ABC cohort were treated with standard tangent fields and 18 were treated with locoregional RT. The non-ABC cohort included 26 patients treated with standard tangents and 12 treated with locoregional RT. A 4- or 5-field technique was utilized in all locally advanced patients to allow for coverage of the supraclavicular fossa and internal mammary lymph nodes with inclusion of low axillary coverage based on individual risk factors. All patients were treated with 3D-conformal techniques utilizing multi-leaf collimators to block the heart. Comparisons were made between mean heart dose, heart V5, mean lung dose, and lung V5 with and without the use of ABC. Kruskal-Wallis tests were used to determine significance between groups with α for significance set at p ≤0.05. Results: On combined analysis, the use of DIBH with ABC resulted in a reduction in heart V5 (1.5 versus 5.4%; p=0.018). Mean heart dose, mean lung dose, and lung V5 were not significantly improved with the use of ABC. On subgroup analysis, patients treated with locoregional RT had reduced mean heart dose (161 cGy versus 309 cGy; p=0.014) and heart V5 (2.3% versus 14.8%; p<0.001) compared to patients treated with a standard free-breathing technique. Conclusions: The use of ABC provided a significant reduction in heart V5 in all patients with left-sided breast cancer and in mean heart dose and heart V5 in patients treated with locoregional RT. This retrospective, single-institution analysis demonstrates the feasibility of implementing moderate DIBH with ABC technology in the treatment of left-sided breast cancer in a community radiation oncology center. Citation Format: Gogineni ES, Kehrer JD, Jones GC, Premo C, Stinson S. Active breathing control in the management of left-sided breast cancer with irradiation: A dosimetric analysis of cardiac and lung dose. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P3-12-06.