ESTRO 2024 - Abstract Book

S689

Clinical - Breast

ESTRO 2024

Fellin, F., Iacco, M., D’Avino, V., Tommasino, F., Farace, P., Palma, G., … & Cella, L. (2019). Potential skin morbidity reduction with intensity-modulated proton therapy for breast cancer with nodal involvement. Acta Oncologica, 58(6), 934-942. https://doi.org/10.1080/0284186x.2019.1591638

2879

Digital Poster

Continuous Positive Airway Pressure in Radiotherapy in Breast Cancer: A Prospective Trial

Jung Bin Park 1,2 , Bum-Sup Jang 1 , Hak Jae Kim 1,2 , Jaeman Son 1 , Seho Kwon 3 , Hyun-Woo Shin 4 , Ji Hyun Chang 1,2

1 Seoul National University Hospital, Radiation Oncology, Seoul, Korea, Republic of. 2 Seoul National University College of Medicine, Radiation Oncology, Seoul, Korea, Republic of. 3 Seoul National University Hospital, Transitional Year Internship, Seoul, Korea, Republic of. 4 Seoul National University College of Medicine, Obstructive Upper Airway Research Laboratory, Seoul, Korea, Republic of

Purpose/Objective:

Radiation exposure of the heart is associated with the risk of ischemic heart disease for patients with breast cancer who underwent radiotherapy. Various approaches, including deep inspiration breast hold, gating, and real-time tracking, have been employed to minimize radiation to normal organs, however, these techniques have limitations, such as extended treatment times, the need for patient cooperation, and costs. Continuous Positive Airway Pressure (CPAP), a current treatment device for sleep apnea, demonstrated significant volumetric and dosimetric benefits with CPAP in radiotherapy for lung and left-sided breast cancer 1) . This study aimed to evaluate the organ sparing effects and tolerability of continuous positive airway pressure (CPAP) utilization in left-sided breast cancer patients receiving postoperative radiotherapy by changes in lung volume and cardiac position.

Material/Methods:

We performed a prospective single-institutional trial. All patients with left-sided or bilateral breast cancer underwent radiotherapy to the breast, axilla, internal mammary nodes, and supraclavicular nodes, except for one patient who did not receive radiotherapy to the supraclavicular region due to re-irradiation. Radiation dose to the breast and regional nodes were 43.2 – 45.9 Gy in 16 – 17 fractions, and tumor bed boost was sequentially delivered 9.6 – 12.5 Gy in 4 – 5 fractions. Volumetric modulated arc therapy planning was applied to all patients. Patients were trained to breathe with a CPAP device using a facial mask with pressures ranging from 6 to a maximum of 20 cm H 2 O. 4D-computed tomography simulation and treatment planning were performed twice for each patient: once with free breathing (FB) and again with CPAP (CPAP). In treatment plans, volumetric and dosimetric parameters of organs at risk (lung, heart, and liver) and deviation of heart centroid were compared. Adverse events were examined on the simulation day, the start date of the treatment, the end date of the treatment, and 2 months after the treatment.

Results: