ESTRO 2025 - Abstract Book

S623

Clinical - Breast

ESTRO 2025

4334

Poster Discussion Patient reported respiratory symptoms 11 years after loco-regional breast cancer radiotherapy: Look for other causes than radiotherapy Maja B. Sharma 1 , Lasse H. Refsgaard 2,3 , Elisabeth Bendstrup 4,3 , Emma S. Buhl 2,3 , Robert Zachariae 5,1,3 , Rasmus B. Friis 1 , Stine S. Korreman 2,3 , Birgitte V. Offersen 1,3,6 1 Department of Oncology, Aarhus University Hospital, Aarhus, Denmark. 2 Danish Centre for Particle Therapy, Aarhus University Hospital, Aarhus, Denmark. 3 Department of Clinical Medicine, Aarhus University, Aarhus, Denmark. 4 Department of Respiratory Diseases and Allergy, Aarhus University Hospital, Aarhus, Denmark. 5 Department of Psychology and Behavioural Sciences, Aarhus University, Aarhus, Denmark. 6 Department of Experimental Clinical Oncology, Aarhus University Hospital, Aarhus, Denmark Purpose/Objective: Breast cancer survivors with respiratory symptoms frequently contact The Danish Patient-Association of Late-effects, suspecting the reason is previous adjuvant radiotherapy. This study investigated patient-reported respiratory symptoms in patients treated with locoregional adjuvant radiotherapy for node-positive breast cancer and evaluated the associations of the responses with the individual radiation doses to the ipsilateral lung. Material/Methods: Patient-reported outcomes and radiotherapy plans were collected from patients treated in a single institution 2008 2016 and included in the DBCG RT Nation Study. The patients answered questions on the presence and severity of dyspnoea (4-point scale, EORTC QLQ-C30) and cough (5-point scale, PRO.CTCAE), smoking, and pulmonary and cardiac comorbidities. Dyspnoea and cough scores were converted to a scale ranging from 0 to 100. Radiotherapy plans were evaluated, and the dose volume parameters to the ipsilateral lung were registered, including mean lung dose (MLD) and the volume receiving 5Gy (V5) and 20Gy (V20). Responders were separated into tertiles based on MLD (‘low’/’intermediate’/’high’). Patient-reported outcomes and comorbidities were reported per group and compared using One-way ANOVA and Chi-squared test. Secondly, responders were dichotomised based on dyspnoea (‘no/little’ vs. ‘quite a bit/very much’) and coughing ('none/mild' vs. 'moderate/severe/very severe'). MLD, 5V and V20 were compared between groups using the two-sample t-test. Results: A total of 1011 questionnaires were sent out, of which 537(53%) were completed. The mean age of responders was 65.7years (SD 9.9); mean time from radiotherapy to questionnaire response was 11years (SD 2.3). Mean overall dyspnoea and cough scores were 17.9(SD 23.6) and 15.7(SD 24.2), respectively. Differences in dyspnoea and coughing scores between dose groups were small and statically insignificant with a tendency towards higher scores for lower MLD. ( Table 1 ). There was no indication of increasing respiratory symptoms with increasing lung dose ( Figure 1 ). For responders reporting ‘no/little’ dyspnoea MLD was 13.0Gy (SD 2.7) vs. MLD 12.0Gy(SD 3.0) for responders reporting ‘quite a bit/very much’ dyspnoea, (p=0.43). For coughing, MLD was 13.0 Gy(SD 2.7) for responders reporting ‘none/mild’ coughing vs.12.5Gy (SD 3.1) for responders reporting ‘moderate/severe/very severe’ cough (p=0.23). The same trends were found for V5 and V20.