R Gupta*, M Huq, UPMC Hillman Cancer Center and University of Pittsburgh School of Medicine, Pittsburgh, PA

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  R Gupta

PO-GePV-T-264 (Sunday, 7/25/2021)   [Eastern Time (GMT-4)]

Purpose: Radiation dose to the heart during breast radiotherapy (RT) has been associated with increased risk of ischemic heart diseases. In our clinic about three years ago, we started deep inspiration breath hold (DIBH) technique using Active Breathing Coordinator (ABC) device for reducing mean heart dose (MHD) in suitable left-sided breast cancer (LBC) patients.

Methods: Out of 120 LBC patients treated with 3D/field-in-field plans during the last three years, 80 were found suitable candidates for using ABC. These patients underwent training with the ABC device (Elekta Oncology, Stockholm, Sweden), during which lung capacity, optimal breath hold duration and level, patient comfort and compliance were assessed. Out of these 80 patients, 12 patients declined using ABC; 33 patients did not require DIBH/ABC use due to a negligible volume of heart within the treatment fields as determined via a free-breathing (FB) CT scan and remaining 35 patients underwent CT simulation with both FB and ABC for comparison of dosimetry. The median prescription dose was 42.56Gy plus 10Gy boost. All 35 patients were treated using ABC on Elekta Infinity via automated response gating interface.

Results: Out of 80 eligible patients, 35 patients received RT using ABC, corresponding to 44% procedural success. Use of ABC in LBC patient’s RT course reduced MHD by 20% or greater when compared with MHD from FB based planning. The median values for absolute and relative reduction in MHD were 1.4 Gy and 65%, respectively.

Conclusion: ABC device during RT should be considered to reduce MHD and hence the risk of ischemic heart disease in left-sided breast patients. However, high proportion of the LBC patients were ineligible due to poor tolerability of the device. DIBH with the ABC device remains preferred approach for cardiac sparing. Data for additional patients treated with ABC device will be added to this analysis

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Taxonomy

TH- External Beam- Photons: General (most aspects)

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