Impact of breath-hold technique on incidence of cardiac events in adjuvant left breast cancer irradiation

Background: This study aims to compare the incidence of cardiac events and to identify its predictors in left breast cancer patients receiving adjuvant radiotherapy using breath-hold technique (DIBH) versus free breathing technique (FB). Methods: We conducted a retrospective multi-center study of two arms; the free breathing arm included 208 patients who were treated with traditional radiotherapy treatment technique, while DIBH arm included 224 patients who were treated with breath-hold technique using The Varian Real-time Position Management (RPM). We retrospectively reviewed the medical records of the patients from January 2010 to December 2017. Results: The mean dose to the heart and left anterior descending artery were significantly lower in the DIBH arm (2.10 ± 0.39 and 6.16 ± 0.18 Gy) compared with (4.29 ± 0.60 Gy and 12.69 ± 0.93 Gy, respectively) in the FB arm. The incidence of cardiac events was higher in the FB arm than in the DIBH arm, but it was not statically significant. Our analysis revealed that age, diabetes, hypertension, smoking, mean LAD dose, and heart mean dose were significant prognostic factors for the occurrence of cardiac events in the breath-hold arm. Hypertension, smoking, as well as heart mean dose were independent risk factors for the occurrence of cardiac events. Conclusion: Use of the DIBH technique resulted in a significant reduction in doses to the heart, LAD and lesser cardiac events incidence compared to free breathing.