S286
Clinical - Breast
ESTRO 2026
Digital Poster 2732
no difference between regimens. As OS was a secondary endpoint in both trials, the clinical relevance remains uncertain. To address this, we analyzed real-world outcomes in a large cohort of breast cancer patients indicated for nodal irradiation from the population-based Baden-Wuerttemberg Cancer Registry (BWCR), Germany. Material/Methods: Patients with invasive breast cancer and indicated for regional nodal irradiation diagnosed 2009-2023 were identified from the BWCR. Radiotherapy schedules were classified as HFRT or CFRT based on total dose and treatment duration. OS and progression-free survival (PFS) were estimated using Kaplan-Meier analysis, and multivariate Cox regression was performed adjusting for age, tumor grading, location, histology, pT/pN stage, lymphatic invasion, type of surgery, systemic therapy, and receptor subtype. Subgroup analyses were conducted across TNM categories and key clinicopathological and treatment- related variables. Results: Among 8,902 eligible patients (median age 62 years), 19.5% received HFRT and 80.5% CFRT, with a median follow-up of 67 months. Survival outcomes were primarily determined by patient and tumor characteristics, including age, tumor stage, and receptor status. In patients younger than 70 years, no statistically significant difference in OS was observed between HFRT and CFRT in multivariable Cox regression (HR 1.22, 95%CI 0.95-1.55, p = 0.115), and fractionation type showed no independent prognostic impact. In contrast, among patients aged ≥ 70 years, OS was significantly worse with HFRT compared with CFRT (HR 1.37, 95%CI 1.16-1.61, p < 0.001), with an effect magnitude comparable to (y)pT/pN stage or receptor profile. PFS did not differ significantly between HFRT and CFRT across all ages (HR 1.10, 95%CI 0.94-1.30, p = 0.2). Conclusion: Real-world data from nearly 9,000 breast cancer patients in the BWCR indicate that PFS across all age groups and OS in patients younger than 70 years were comparable between HFRT and CFRT. In patients aged ≥ 70 years, HFRT was associated with worse OS, with an effect magnitude similar to key prognostic factors.The differing findings of HypoG-01 and SKAGEN may therefore reflect variations in patient selection, tumor characteristics, and systemic treatment rather than a causal effect of radiotherapy fractionation itself. Keywords: Hypofractionation, nodal irradiation, real- world
Impact of Advanced IMRT/VMAT Techniques and Supportive Care Strategies on Acute SkinToxicity in Whole-Breast Radiotherapy Gabriella Macchia 1 , Mara Fanelli 2 , Pezzulla Donato 1 , Paolo Bonome 1 , Carmela Romano 3 , Savino Cilla 3 , Francesco Deodato 1,4 , Mariangela Boccardi 1 1 Radiation Oncology Unit, Responsible Research Hospital, Campobasso, Italy. 2 Research Laboratories, Responsible Research Hospital, Campobasso, Italy. 3 Medical Physics Unit, Responsible Research Hospital, Campobasso, Italy. 4 Istituto di radiologia, Università Cattolica del Sacro Cuore, Roma, Italy Purpose/Objective: Acute skin toxicity is the most common side effect of adjuvant radiotherapy (RT) for breast cancer (BC), with grade ≥ 2 dermatitis reported in 10–50% of cases [1–3]. This retrospective–prospective cohort study compared the incidence of acute skin toxicity in patients receiving whole-breast RT and using either standard emollient creams or the LimpiAD® 2.5% Plus medical device (Aileens Pharma s.r.l.) for supportive care. Material/Methods: BC patients treated with whole-breast RT ± tumor-bed boost using IMRT/VMAT techniques and breath-hold when indicated were included. Supportive care consisted of either standard emollient creams (n = 315) or LimpiAD® 2.5% Plus (n = 157). Acute skin toxicity was assessed at baseline, 1 month, and 6 months post-treatment using CTCAE v5.0, and group differences were analyzed with Pearson’s chi-square test. Results: A total of 472 patients treated between September 2016 and February 2025 were included (Table 1).
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