ESTRO 2025 - Abstract Book

S441

Clinical - Breast

ESTRO 2025

539

Digital Poster ADJUVANT RADIOTHERAPY IMPACT ON FATIGUE IN BREAST CANCER PATIENTS: A 10-YEAR SINGLE INSTITUTIONAL EXPERIENCE IN 1002 PATIENTS. Donato Pezzulla 1 , Mariangela Boccardi 1 , Savino Cilla 2 , Gabriella Macchia 1 , Carmela Romano 2 , Sara Di Pasquale 1 , Gianpiero Mastrogiorgio 1 , Paolo Bonome 1 , Marica Ferro 1 , Vincenzo Picardi 1 , Milly Buwenge 3 , Alessio Giuseppe Morganti 3,4 , Francesco Deodato 1,5 1 Radiation Oncology Department, Responsible Research Hospital, Campobasso, Italy. 2 Medical Physics Department, Responsible Research Hospital, Campobasso, Italy. 3 IRCCS Azienda Ospedaliero-Universitaria di Bologna, Radiotherapy, Bologna, Italy. 4 Department of Medical and Surgical Sciences (DIMEC), Alma Mater Studiorum Bologna University, Bologna, Italy. 5 Istituto di Radiologia, Università Cattolica del Sacro Cuore, Roma, Italy Purpose/Objective: Fatigue is one of the most common symptoms reported by cancer patients with negative consequences on patients' daily social life and quality of life, even after treatments. Herein we evaluated the impact of radiotherapy (RT) on the fatigue of breast cancer (BC) patients. Material/Methods: BC patients who received an adjuvant RT treatment between 2009-2019 and with at least one year of follow-up were retrospectively analyzed. Patient's characteristics including age and comorbidities, treatment factors such as Hormonal Therapy (HT), Chemotherapy (CT), RT dose and fractionation, and related toxicities were registered. Fatigue level was measured through the Cancer Linear Analogue Scale (CLAS) for quality of life (CLAS1), energy level (CLAS2), and ability to perform daily activities (CLAS3). These parameters were assessed before RT[T0], at one month [T1], and twelve months [T2]. Two Scores (ScRT10 and ScRT20) were obtained by subtracting the CLAS values at T1 and T2 from the T0 values. A decrease of ≥ 2 points in quality of life, energy level, and ability to perform daily activities was considered clinically significant for RT-related fatigue onset. Results: 1002 patients were evaluated. Median age was 59 years (range, 27-85). RT was delivered in 16 or 25 fractions in 33% and 67%, respectively. HT and CT were administered in 95% and 54% of the overall population, respectively. At T1, the RT-related fatigue onset (decrease of CLAS1, 2, and 3 values) was observed only in 9.5%, 12.1%, and 12.4% of the overall population, respectively. Similarly, at T2, the RT- related fatigue onset was observed only in 12.7%, 16.1%, and 15.7% of patients, respectively. In the logistic regression investigating variables increasing the RT-related fatigue onset, we found that acute RT toxicity > G1 reduced the energy level at both T1 and T2 (p:0.042 and p:0.006, respectively), while HT mainly reduced the quality of life and ability to perform daily activities at T2 (p: 0.025 and p: 0.023, respectively). Surprisingly, previous CT administration was associated with reduced RT-related fatigue, as expressed by an increase in all CLAS values (p<0.001) (Table 1).