Dose advantage of abdominal deep inspiratory breath-hold (aDIBH) in postoperative adjuvant radiotherapy for left breast cancer.

Purpose: We explored the dosimetric efficacy of the abdominal deep inspiration breath hold (aDIBH) technique using an audio-guided device in patients with left breast cancer undergoing postoperative adjuvant radiotherapy compared to free breathing (FB).

Methods: A total of 35 patients with early stage left breast cancer underwent two computed tomography simulation scans each with aDIBH and FB after breast-conserving surgery. Treatment planning was optimized using the Pinnacle³ 9.10 planning system. The heart, left anterior descending coronary artery (LADCA), and left lung was defined as organs at risk (OARs). The dosimetric differences in the planning target volume (PTV) and OARs were compared between aDIBH and FB.

Results: Compared with FB, the heart moved farther caudally and away from the chest wall, and the volume of heart became smaller under aDIBH due to expansion of the lungs. The D mean of the heart, LADCA and left lung of aDIBH were respectively reduced by 332.79 ± 264.61 cGy (P < 0.001), 1290.37 ± 612.09 cGy (P < 0.047) and 69.94 ± 117.73 cGy (P < 0.001). The V20 and V30 of the OARs were also significantly reduced with statistical differences (P < 0.05). In addition, there was no significant difference in the dosimetric parameters of the PTV between the two groups (P > 0.05).

Conclusions: Implementation of the aDIBH technique for postoperative radiotherapy after breast-conserving surgery of the left breast cancer could reduce irradiation of the heart dose, LADCA dose and left lung dose, without compromising target coverage.