ESTRO 2025 - Abstract Book

S519

Clinical - Breast

ESTRO 2025

Material/Methods: This is a retrospective series covering a 5-year period from January 2018 to January 2023, analyzing cases of non metastatic inflammatory or locally advanced breast cancer, non-resectable after neoadjuvant chemotherapy, in which CRT with capecitabine was proposed. All patients received neoadjuvant chemotherapy based on anthracyclines and taxanes. Post-chemotherapy therapeutic response evaluation showed the tumor to be non resectable. Radiotherapy was delivered using a 3D conformal mono-isocentric technique to the entire breast and the supra-clavicular, sub-clavicular, and axillary lymph nodes, with a standard fractionation regimen of 50 Gy over 5.4 weeks, using a 5 mm bolus. The concurrent chemotherapy consisted of capecitabine at a dose of 825 mg/m² twice daily on radiotherapy days. Follow-up included clinical, biological, and radiological assessments. Results: A total of 18 patients were included in the study, with a median age of 46.2 years. 47% of the patients were premenopausal. The median consultation delay was 8.75 months. Histologically, all patients had invasive ductal carcinoma of the NOS (not otherwise specified) type. 58% were classified as grade 2 SBR, and 42% as grade 3. The median Ki-67 index was 62%. 52% expressed hormone receptors. One patient had HER2 overexpression. Patients received an average of 7 cycles of neoadjuvant chemotherapy (anthracyclines followed by taxanes) but were found to be inoperable. CRT with capecitabine was then proposed. All patients received weekly follow-up, including clinical, biological, and imaging assessments. Toxicity was evaluated according to CTCAE (v.4.0). The treatment was well tolerated, and no cases of grade 4 toxicity were reported. Hepatic cytolysis was the main toxicity, affecting 7 patients, but it did not require treatment cessation. Radiation dermatitis was observed in all patients, with grade 3 in 2 patients, which required treatment interruption for specialized management. For the others, topical treatment was provided. Additionally, 15 patients developed grade 1/2 esophagitis, which was treated symptomatically. At the end of the CRT, 22% patients were able to undergo salvage surgery. The median overall survival was 7.2 months (range: 2–22 months). Conclusion: CRT is an interesting alternative for non-resectable inflammatory/locally advanced breast cancers after neoadjuvant chemotherapy. A multicentric study with a larger patient sample should be considered to define an appropriate protocol.

Keywords: radiochemotherapy, locally advanced, breast cancer

2319

Digital Poster Clinical evaluation of cost-effectiveness of the DIBH technique versus free breathing in breast cancer with the Fast Forward scheme. Luz Rubí Olea, Francisco Alvarez Rico, Ana Gonzalez Morales, Omar Rodríguez Pérez, Raquel Delgado Rico, José María Azcoaga Blasco Radiation Oncology, Regional University Hospital, Malaga, Spain Purpose/Objective: To conduct a clinical cost-effectiveness study comparing the Deep Inspiration Breath Hold (DIBH) technique against free breathing in the treatment of breast cancer. Adjuvant irradiation in left breast cancer entails exposure of the heart and left lung, which poses risks of cardiovascular and pulmonary morbidity. We have analyzed the routine cost effective implementation of the DIBH technique in our department compared to free breathing, evaluating Dose Distribution, Total Treatment Time, Quality of Life Related to Subjective Stress Levels.