ESTRO 2022 - Abstract Book

S1019

Abstract book

ESTRO 2022

PO-1197 ABC: A Breast Cardiac sparing RT

E. Bonzano 1 , M. Cavallari 2 , R. Di Liberto 2 , A.R. Filippi 1

1 IRCCS San Matteo Polyclinic Foundation, Department of Radiation Oncology, Pavia, Italy; 2 IRCCS San Matteo Polyclinic Foundation, Department of Medical Physics, Pavia, Italy Purpose or Objective 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. Materials and Methods 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. Results 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. Conclusion 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. 1 Centre de radiothérapie de Mâcon, Saône et loire, Mâcon, France; 2 Neural, Hérault, Montpelier, France; 3 Vision RT, London, London, United Kingdom Purpose or Objective To investigate the reproducibility of deep-inspiration breath hold (DIBH) breast cancer treatments on Halcyon™ performed using the first clinical version of AlignRT InBore™. Materials and Methods The ease and feasibility of DIBH treatments was retrospectively investigated for the initial 22 left breast cancer patients treated on Halcyon™ using the first clinical version of AlignRT InBore™. Setup time, CBCT imaging and analysis time as well as overall treatment time were recorded. Online and offline review of CBCT images was undertaken to verify the compliance of breast, heart, spine, sternum and lung domes positions. Results Mean ± standard deviation for patient setup, CBCT analysis and overall treatment time were 4 ± 0.6 min, 1.1 ± 0.2 min and 14 ± 1.8 min respectively. Online review of 520 CBCT acquisitions showed minimal positioning shifts with AlignRT InBore™ guidance with mean ± standard deviation of vertical, longitudinal, and lateral shifts of 1.7 ± 2.5 mm, -1.7 ± 3.8 mm, and - 0.2 ± 2.5 mm respectively. Meanwhile, offline review of 115 CBCTs, showed reproducible BH with average ± standard magnitude deviation of breast, heart, spine, sternum and lung domes within 2.3 ± 2.4 mm, 2.9 ± 2.0 mm, 3.3 ± 2.2 mm, 3.2 ± 2.4 mm and 5.0 ± 6.7 mm respectively. Conclusion AlignRT InBore™ allows for accurate and reproducible DIBH on Halcyon™ with breast and heart organs’ positions within 3 mm (in magnitude) of expected position and fully compliant with local clinical and dosimetry margins. PO-1198 CBCT review confirm reproducible DIBH with AlignRT InBore D. NGUYEN 1 , F. Lorchel 1 , A. Mamou 2 , N. Barbet 1 , I. Pouchard 1 , F. Renoult 1 , J. Farah 3 , M. Khodri 1

PO-1199 LONG TERM TOXICITY OF OARS AFTER ADJUVANT RADIOTHERAPY IN BREAST CANCER PN1 WITH OR WITHOUT ALND.

M.D. DE LAS PEÑAS CABRERA 1 , S. PAYANO HERNANDEZ 1 , P. SAMPER OTS 1 , E. AMAYA ESCOBAR 1 , J. ZAPATERO ORTUÑO 1

1 UNIVERSITY HOSPITAL REY JUAN CARLOS, ONCOLOGY RADIATION, MADRID, Spain