ESTRO 2025 - Abstract Book

S444

Clinical - Breast

ESTRO 2025

580

Digital Poster Hypofractionated Radiation Therapy in high risk node positive Breast Cancer: a retrospective study. Cheikh TAYEB, Amine El Rhazi YEZLI, Sofiane MELLOUK Radiation Oncology, Central Hospital Of Army, Algiers, Algeria Purpose/Objective: Radiation Theray plays a major role in the management of breast cancer. Hypofractionated is currently recommended by several international guidelines for early breast cancer without nodal involvement ; however The data on moderate hypofractionated radiotherapy for breast cancer in cases of nodal irradiation are limited.The goals of our retrospective study were to evaluate the safety and efficacy of moderate hypofractionated of breast/ thoracic wall and locoregional lymph node radiotherapy in 15 fractions. Material/Methods: From january 2017 to june 2019, 261 patients with invasive breast cancer and positive lymph nodes received an adjuvant moderate hypofractionated radiotherapy treatment of the breast and/or chest wall and lymph node at the radiation oncology department of Central Hospital Of Army in Algiers. All patients were treated with 3-dimensional Field In Field conformal radiotherapy technique (3- D FIF ), using a linear accelerator with photon beams of 6 to 18 MV of energy The Planning Target Volume (PTV) included the thoracic wall, pectoral muscle and the lymph nodes of the III and IV ipsilateral level. A total dose of 40.05 Gy was delivered to the chest wall and lymph nodes in 16 fractions of 2.67 Gy. Results: The Median patient age was 51.3 years (range 24-82 years). 51.3% left tumors, 48.7% right tumors. Immunohistological 23.7% and 12.3% patients were HER 2 positive and triple negative tumors respectively. According to the AJCC 8th Edition standard, there were stage IA in 14.2% patients, stage IIA in 32.6% patients, stage IIB in 23% patients, stage IIIA in 13.8%, in patients, stage IIIB in 16.1% and stage IIIC in 0.3% patients. Neoadjuvant and adjuvant chemotherapy were administered to 36% and 74 % of patients respectively. A mastectomy with ipsilateral axillary dissection were performed in all patients. With a median follow-up of 60 months, we reported 20.6% lymphedema (17.2% grade 1 and 3.4% grade 2), 3.4% skin fibrosis, 4.6% hypothyroidism, 0.3% brachial plexopahy, 0.3% ischemic heart disease. Regarding disease control, local and regional recurence were observed in 3.1 %of patients, there were 15.3% of distant metastasis. For survival: local-regional and metastatic recurrence-free survival at 5 years were 96.9% and 84.7% respectively. Conclusion: The excellent disease outcomes and acceptable toxicity profiles of our series, similar to other studies. Moderate hypofractionation could be an effective, safe and practical therapeutic approach for locally advanced breast cancer, based on radiobiological considerations of the breast tumor, delivering shorter treatment regimens. References: 1/Hypofractionated Radiation Therapy (HFRT) of Breast/Chest Wall and Regional Nodes in Locally Advanced Breast Cancer: Toxicity Profile and Survival Outcomes in Retrospective Monoistitutiona Author links open overlay panelSara De Matteis, Giuseppe Facondo, Maurizio Valeriani, Gianluca Vullo, Vitaliana De Sanctis, Anna Maria Ascolese, Barbara Campanella, Giovanna Scalabrino, Mattia Falchetto O /Clinical Breast Cancer,Volume 22 2/Randomized Prospective Study Comparing Conventional Versu Hypofractionated Adjuvant Radiotherapy in Node Positive Breast Cancer Mai Atef, Eman El Sheikh, Mahmoud A. Ellithy, Khaled Naguib, Amr S. Tawfik Research in Oncology 2019; Vol. 15 Keywords: Breast cancer , hypofractionated , high risk