ESTRO 2023 - Abstract Book

S1023

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ESTRO 2023

Results Mean MHD in our cohort was 1.62Gy and median dose was 1.24Gy (range 0.38 Gy to 9.99 Gy).

MHD was significantly higher in postmastectomy vs conservative surgery (2.47 vs 1.27; p < 0.001); in nodal irradiation group (2,20 vs 1,14 p < 0,001); in internal mammary radiation group (3.00 vs 1.45 p < 0,001); and progressively increased with a higher stage of the disease. (Fig 1)

Conclusion DIBH achieved a low dose of radiation to the heart but there are technical and clinical factors that directly influence in the MHD.

PO-1280 Optical coherence tomography computational model to quantify radiotherapy induced skin effects

M. Mollà 1 , G. Oses 2 , G. Tena 3 , M. Combalia 3 , A. Combalia 3 , P. Iglesias 4 , B. Alejo 3 , A. Huguet 1 , S. Garrido 1 , J. Solà 1 , C. Carrera 3 1 Hospital Clínic Barcelona, Radiation Oncology, Barcelona, Spain; 2 Hospital Clínic, Radiation Oncology, Barcelona, Spain; 3 Hospital Clínic Barcelona, Dermatology, Barcelona, Spain; 4 Hospital Clinic Barcelona, Dermatology, Barcelona, Spain Purpose or Objective Acute radiodermitis remains the most common adverse effect of whole breast radiation therapy (WBRT) in patients with breast cancer (BC). There is currently no objective and reproducible method to measure this effect, nor is there a standardized adjuvant therapy to prevent it. Optical Coherence Tomography (OCT) imaging of skin could be a promising tool in clinical management and research of several skin conditions. The primary objective was to demonstrate skin changes induced by WBRT with OCT scanning. Secondary objectives are to compare radiodermitis grade related to the various radiotherapy (RT) regimes and their impact on quality of life. Materials and Methods An observational, prospective study of 39 BC patients and candidates to WBRT were grouped by fractionation: 15 fractions (total dose 40.05 Gy) 38.46% of the patients, 20 fractions (total dose 40.05 Gy plus 13.35 Gy to the tumor bed) 35.89% of the patients and 25 fractions (total dose 50 Gy and 57.5 Gy to the tumor bed) 24.64% of the patients. Patients were studied by clinical examination (CTCAE 3.0), quality-of-life questionnaire (EORTC QLQ-C30), and OCT at baseline, the end, and 3 months after completing RT. OCT volumes were processed following an algorithm developed by a biomedical engineer to