ESTRO 2025 - Abstract Book

S538

Clinical - Breast

ESTRO 2025

Material/Methods: A systematic literature search was performed using PubMed, Cochrane and Embase electronic databases. Inclusion criteria were: (1) randomised controlled trials and prospective cohort studies, (2) female breast cancer patients (≥18 years) treated with external beam breast radiotherapy and/or brachytherapy, (3) studies collecting data on breast oedema following breast radiotherapy. Exclusion criteria included: (1) retrospective studies, (2) review articles, case reports/series, (3) non-English language, (4) recruitment commencing before 1999, as a proxy for excluding trials using older radiotherapy techniques. This study followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Results: A total of 3361 abstracts were identified and 333 corresponding articles reviewed. Seventy-five studies (19 RCTs and 56 prospective cohort studies) met inclusion criteria. Dose/fractionations varied between 21Gy/1# and 50.4Gy/28#. Twenty-seven studies reported breast oedema at end of radiotherapy, 16 studies at 3 months, 19 studies at 6 months, 17 studies at 12 months, 30 studies between 1-5 years and 2 studies at 10 years. The incidence of breast oedema ranged from 0-74% at end of radiotherapy, 3-62% at 3 months, 0-36% at 6 months, 0-63% at 12 months, 0 26% at 1-5 years and 0-3% at 10 years (sub-classification in Table 1). Seventy-three trials reported clinician-reported breast oedema, of which 40 used CTCAE, 17 used LENT-SOMA, 18 used RTOG/EORTC and 6 used a 4-point Likert scale. Eight trials reported patient-reported breast oedema outcomes, of which 5 studies used questionnaires based on EORTC QLQ-BR23. Patient-reported incidence of breast oedema ranged between 5-16% within 6 months following radiotherapy and 2-16% at 12 months.

Conclusion: The incidence of breast oedema, in the studies that measure it, appears highest at the end of breast radiotherapy then declines. The most prevalent tool in use was CTCAE. To refine our understanding of the timeline and contributing factors to breast swelling, it is recommended, in future trials, that more detailed clinician and patient reported data on breast swelling be collected in the weeks after radiotherapy.

Keywords: breast oedema, radiotherapy