Abstract Introduction: Breast edema is a frequently under-reported and increasingly prevalent complication of breast cancer surgery. Currently, no unified definition or standardised diagnostic criteria exists, and there is limited evidence regarding its effective management and preventative strategies. The current literature suggests that breast edema is a long-term sequela of treatment, with a significant negative impact on patients’ quality of life. Methods: A systematic review of the literature was conducted according to PRISMA guidelines, examining the risk factors, diagnostic criteria, and management of breast edema following breast cancer surgery. Two independent reviewers conducted a comprehensive search of the Cochrane Library, PubMed, EMBASE, and additional sources from January 2000 to June 2025. Results: An initial keyword search identified 269 studies; following the application of eligibility criteria, 23 studies were included, encompassing 3,806 female patients with a mean age of 58.5 years-old, and an average BMI of 27.9. Of the included patients, 93.4% (n = 3,555) had undergone breast-conserving surgery, 4.4% (n = 168) have had mastectomies with free-flap or expander prosthesis reconstructions, and 2.2% (n = 83) have had therapeutic or prophylactic mastectomies without reconstruction. One study investigated breast edema in oncoplastic surgery, reporting this as a risk factor. Of the studies included, 21 reported on breast edema following adjuvant radiotherapy, despite inconsistencies in reporting, the most commonly cited radiotherapy schedule was 50Gy/25#. 39.1% (n = 9) of the articles investigated risk factors of breast edema, patient-related factors such as increased BMI and breast cup size were consistently reported as positive predictors of breast edema. There were conflicting findings with regards to tumour size and location, nodal involvement, and the extent of axillary surgery in relation to breast edema. Adjuvant radiotherapy and tumour bed boosts were associated with increased breast-edema, peaking at three to six months post-radiotherapy. Further potentially modifiable risk factors such as wound infection, and segmental post-operative scar-tissue burden were also proposed across studies. The reported incidence of breast edema following adjuvant radiotherapy was extremely variable, ranging from 7.1% to 75.5%, with high discordance based on the variability of definition and diagnostic methods. 43.5% (n = 10) of included studies focussed on the diagnosis of breast edema, including patient-reported outcomes measured with breast-edema related questionnaires, clinical examination, and imaging. Emerging investigations include dermal thickness measurement using High Resolution Ultrasound (HRUS) and tissue dielectric constant (TDC) as an accurate, non-invasive, and efficient quantitative measures of breast edema. Various studies have reported an inter-breast TDC ratio 1.40 as diagnostic for breast edema, while consensus has yet to be reached for the dermal thickness diagnostic threshold. The management and prevention of breast edema remains largely under-reported, with 17.4% (n =4) of included studies reporting this. Management options investigated in this review include compression garments, structured exercise programs and manual lymphatic drainage, though evidence supporting their efficacy remains inconsistent. Conclusion: Breast edema is a commonly overlooked but profoundly debilitating complication of breast cancer surgery, its aetiology is multifactorial, complex and distinct to breast-cancer related lymphedema of the arms. Improved prevention strategies, more timely and accurate diagnosis, and further assessment of more treatments is essential to optimise patient outcomes and quality of life. Citation Format: J. El-Taraboulsi, C. Rossou, M. Boland, D. Leff, S. Cleator, V. Harding, P. Thiruchelvam. Breast Edema Following Breast Cancer Surgery: A Systematic Review of Risk Factors, Diagnosis and Management abstract. In: Proceedings of the San Antonio Breast Cancer Symposium 2025; 2025 Dec 9-12; San Antonio, TX. Philadelphia (PA): AACR; Clin Cancer Res 2026;32(4 Suppl):Abstract nr PS1-03-08.
El-Taraboulsi et al. (Tue,) studied this question.