S345
Clinical - Breast
ESTRO 2026
this toxicity, we propose the systematic delineation of the PCM to minimize the doses delivered to these structures. Keywords: hypofractionated radiotherapy, dysphagia, toxicity
studied.This study aims to evaluate the incidence and severity of dysphagia in patients treated with hypofractionated LRR for localized breast cancer (LBC). Material/Methods: This is a retrospective study based on the clinical and technical records of 60 patients treated with adjuvant LRR for LBC. The treatment plan was performed using a three-dimensional conformal radiotherapy technique. The radiotherapy dose was 42.5 Gy in 16 fractions with a boost of 10 Gy in 4 fractions to the tumor bed in cases of breast-conserving therapy (35%), and 40 Gy in 15 fractions in cases of radical treatment (65%).We retrospectively delineated the entire esophagus and the pharyngeal constrictor muscles (PCM). From the dose–volume histograms, we recorded the total volume of both structures, their mean (D_mean), minimum (D_min), and maximum (D_max) doses, as well as the percentage of esophageal volume receiving a dose ≥ 17.5 Gy (V17.5) and ≥ 31 Gy (V31), and the volume of the PCM receiving a dose ≥ 36 Gy (V36). These dosimetric constraints were calculated using biologically equivalent dose. Data analysis was performed using SPSS version 20. Results: The mean volumes of the esophagus and the PCM were 29.39 cm ³ [17.80–44.60] and 6.82 cm ³ [2.00– 12.20], respectively. For the esophagus, the median D_mean, D_max, D_min, V17.5, and V31 were 4.26 Gy [0.29–9.99], 30.62 Gy [0.48–49.96], 0.23 Gy [0.023– 0.65], 7.69% [0.00–25.88], and 1.76% [0.00–20.53], respectively. For the PCM, the median D_mean, D_max, D_min, and V36 were 1.28 Gy [0.07–9.15], 16.80 Gy [0.15–41.19], 0.19 Gy [0.00–0.94], and 0.00% [0.00–3.35], respectively.The following table summarizes the dosimetric data for the esophagus and the PCM:
Poster Discussion 4955
Final acute adverse events of hypofractionated adjuvant breast RT with VMAT and high dose simultaneous integrated boost: the DEBoRa phase II trial Salvatore Minuti 1 , Edy Ippolito 1,2 , Sonia Silipigni 2 , Lucrezia Toppi 2 , Paolo Matteucci 2 , Michele Fiore 1,2 , Carlo Greco 1,2 , Antonella Grasso 3 , Paolo Orsaria 3 , Vittorio Altomare 3 , Sara Ramella 1,2 1 Research Unit of Radiation Oncology, Università Campus Bio-Medico di Roma, Roma, Italy. 2 Operative Research Unit of Radiation Oncology, Fondazione Policlinico Universitario Campus Bio-Medico, Roma, Italy. 3 Department of Breast Surgery, Fondazione Policlinico Universitario Campus Bio-Medico, Roma, Italy Purpose/Objective: DEBORA trial (NCT070021846) is a phase II trial enrolling early stage breast cancer patients <50 years of age with at least one additional risk factor treated with breast conserving therapy and radiotherapy with high dose simultaneous integrated boost (total dose to tumor bed 52.5/3.5 Gy per fraction).Primary endpoint is the 4year rate of fibrosis. Here we report the acute adverse events analysis after the completion of the accrual. Material/Methods: Patients with histologically proven breast cancer who underwent conservative surgery with at least 3 inserted clips on tumor bed and at least one of the following histopathologic additional risk for local recurrence: T >2 cm, N1 disease; unfavourable biology, lymphovascular invasio n; close margins ( ≤ 4 mm) were considered eligible for the trial. Patients were treated with hypofractionated RT to whole breast to a total dose of 40.05 Gy in 15 fractions (2.67 Gy/die) and a simultaneous integrated tumor bed dose of 52.5 Gy (3.5 Gy/die).VMAT planning was used. Acute adverse eventswere evaluated by means of Common Terminology Criteria for Adverse Events (CTCAE) v. 5 scale at the end and three months after the end of treatment Results: Between May 2020 and September 2025,90 consecutive patients, all with an age lower or equal to 50 years old (median 47; range 31-50) were enrolled. Additional risk factor in
Only one case (1.7%) of G3 acute dysphagia (AD) was recorded, along with 8 cases (13.3%) of G1 and 2 cases (3.3%) of G2. Four patients (6.7%) experienced G1 late dysphagia (LD). No cases of G2 or 3 LD were observed.The patient who developed G3 AD had a D_max to the PCM of 41.169 Gy and a V36Gy of 1.590%. Conclusion: Dysphagia is one of the most underestimated complications of LRR in LBC. In the absence of established recommendations for the prevention of
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