S227
Clinical - Breast
ESTRO 2026
Conclusion: The presence of vascular calcifications in simulation- CTs for aRT was associated with a higher risk of chronic breast edema. This finding suggests that subclinical atherosclerosis could be a marker of systemic vulnerability that potentiates the reaction of breast tissue to radiotherapy, which could be incorporated into clinical practice as a personalized toxicity risk stratification tool. References: Teague, H. L., M. A. Ahlman, A. Alavi, D. D. Wagner, A. H. Lichtman, M. Nahrendorf, F. K. Swirski, et al. 2017. “Unraveling Vascular Inflammation: From Immunology to Imaging.” Journal of the American College of Cardiology 70 (11): 1403–1412. https://doi.org/10.1016/j.jacc.2017.07.750.Bouten, Roxane M., Erik F. Young, Reed Selwyn, Diego Iacono, W. Bradley Rittase, and Regina M. Day. 2021. “Effects of Radiation on Endothelial Barrier and Vascular Integrity.” In Tissue Barriers in Disease, Injury and Regeneration, edited by Nikolai V. Gorbunov, 43–94. Elsevier. https://doi.org/10.1016/B978-0-12-818561- 2.00007-2.Libby, Peter. 2002. “Inflammation in Atherosclerosis.” Nature 420 (6917): 868–874. https://doi.org/10.1038/nature01323. Keywords: Vascular calcification, Edema, Risk stratification StrataXRT versus Mepitel Film for prevention of acute radiation dermatitis: pooled intra-patient randomized trials in postmastectomy radiotherapy Shing Fung Lee 1,2 , Patries M Herst 3 , Melissa L James 4,5 , Pui Lam Yip 1,2 , Michael Chao 6,7 1 Department of Radiation Oncology, National University Cancer Institute, National University Hospital, Singapore, Singapore. 2 Department of Medicine, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore. 3 Department of Radiation Therapy, University of Otago, Wellington, New Zealand. 4 Canterbury Regional Cancer and Haematology Service, Christchurch Hospital, Christchurch, New Zealand. 5 Department of Medicine, Christchurch Hospital, University of Otago Christchurch, Christchurch, New Zealand. 6 Genesis Care Victoria, Ringwood Private Hospital, Melbourne, Victoria, Australia. 7 Olivia Newton John Cancer Wellness and Research Centre, Austin Hospital, Heidelberg, Victoria, Australia Purpose/Objective: We report a pooled analysis of two multicenter intra- patient randomized controlled trials (RCTs) comparing the silicone-based dressings Mepitel Film and StrataXRT for the prevention of acute radiation Poster Discussion 944
associated with dosimetric and surgical factors, we propose that it could also be conditioned by a pre- existing biological vulnerability. The presence of thoracic vascular calcifications visible on the simulation CT—as a radiological marker of subclinical atherosclerosis and systemic pro-inflammatory state— could identify patients with greater susceptibility to radiation toxicity. This hypothesis is based on the activation of common pathways of chronic inflammation and microvascular dysfunction, which would compromise lymphatic repair and favor the progression of acute edema to chronicity. Material/Methods:
A retrospective cohort observational study was conducted in early-BC patients treated with breast conserving surgery and who received hypofractionated aRT (40.05Gy/15 fractions) to the breast. Patients in indication for elective axillary treatment were excluded. The main objective was to evaluate the association between the development of chronic breast edema and the presence of thoracic vascular calcifications visually identified on the simulation-CT (Fig.). A multivariate logistic regression model was applied, adjusted for relevant clinical and dosimetric factors: breast volume, age, chemotherapy treatment, and cardio-metabolic comorbidities (diabetes, hypertension and dyslipidemia). Results: A total of 612 patients were included, of whom 8.3% (n=51) developed chronic edema. Thoracic vascular calcifications were identified in 229 out of 612 patients (37.4%). Of these, 97 (15.8%) presented coronary involvement and 211 (34.5%) in other thoracic locations. Furthermore, 79 (12.9%) presented calcifications in both coronaries and other locations simultaneously. Chronic breast edema was observed in 11.4% of patients with thoracic vascular calcifications, compared to 6.5% in those without them (Adjusted-OR: 2.97; 95%CI [1.11–4.69], p=0.025). 15.5% of women with coronary calcifications developed edema, compared to 7.0% in those without coronary involvement (Adjusted-OR: 2.79; 95%CI [1.28–6.10], p=0.010). Classifying based on the distribution of calcifications, the association was even more marked in patients with simultaneous calcifications in coronaries and other thoracic locations, where the risk of edema is almost four times more likely than those without calcifications (Adjusted-OR: 3.82, 95%CI [1.43– 10.20], p=0.007).
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