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Adjuvant radiotherapy(RT) is well known to improve local control and overall survival in patients treated with breast conserving therapy (BCT). 

Part of this gain is counterbalanced by the risk of mortality and morbidity from cardiovascular damage and dysfunction as a result of cardiac exposure to post-surgery treatments. Moderate deep inspiration breath-hold (mDIBH) during radiation treatment delivery helps in reducing the cardiac dose. Our study aim is to evaluate a dosimetric comparison of heart dose with and without active breath coordinator (ABC) mDIBH during tangential field breast cancer radiation.

30 left sided breast cancer patients who underwent breast cancer surgery and adjuvant 3DCRT radiotherapy with ABC mDIBH between November 2020 and October 2021 at Policlinico San Matteo, were analyzed. The ABC device was used for respiratory control and patients who were able to hold their breath for 20–30 s were considered for radiation with ABC mDIBH. Two simulation scans were done, in free-breathing (FB) and ABC mDIBH. 3DCRT treatment plans were generated for each patient. RT was delivered in a regime of 40 Gy in 15 fractions, five times per week. Target coverage and Heart V40Gy and Dmean, left descending coronary artery (LADCA) Dmax, V20Gy and Dmean, were analyzed with dose/volume histograms.

The level of significance was set at P < 0.05. Heart Dmean was 1.23 Gy with FB and 0.90 Gy with ABC (P < 0.0143). LADCA Dmax was 20.63 Gy with FB and 8.98 Gy with ABC (P <0,0001). Target coverage was equal in both the plans.

The use of ABC mDIBH technique resulted in a significant reduction in cardiac and LADCA doses, hence, can be considered as a promising technique for cardiac sparing.