Radiotherapy plays a vital role in breast cancer treatment, but for left-sided breast cancers, radiation exposure to the heart can increase the risk of future cardiac complications. Deep inspiration breath hold involves patients taking a deep breath and holding it during radiation delivery. By expanding the lungs, DIBH increases the distance between the heart and the irradiated breast tissue, potentially reducing radiation exposure to the heart. 

This retrospective study analyzed data from 57 patients with left breast cancer who received DIBH breast radiotherapy at Humanitas Research Hospital (Rozzano, Italy) via EMR review. Data included surgery type, medications (pre and post-radiotherapy), cancer characteristics, and radiotherapy details (dose, lymph node involvement). The Aria system recorded heart and LAD mean/maximum radiation doses, which we compared to established standards to assess DIBH's effectiveness in reducing heart exposure. We also tracked long-term health through EMRs and direct patient contact. 

Our study found that the mean heart dose was 2.34 Gy (standard deviation ± 0.62) and the maximum dose was 15.82 Gy (standard deviation ± 5.74). The mean LAD dose was 5.45 Gy (standard deviation ± 2.21) and the maximum dose was 13.36 Gy (standard deviation ± 5.92). The observed mean and maximum doses to these critical structures fell within the range reported in prior studies employing DIBH and were lower than studies using traditional radiotherapy techniques. Notably, only one out of the 54 followed-up patients experienced adverse cardiac effects. 

The low incidence of adverse cardiac effects observed in our follow-up data (one out of 54 patients) is encouraging. However, it is crucial to acknowledge the limitations of our study, particularly the relatively small sample size. Larger, long-term studies with more patients are needed to definitively establish the risk of cardiac complications associated with DIBH compared to traditional radiotherapy.