S904
Clinical - Mixed sites & palliation
ESTRO 2026
97.5%, with the median not reached (figure 1).
on 2000 patients treated with high-dose type I and II re-irradiation. An interim analysis of mortality and adverse events (AEs) was conducted to evaluate patient selection, assess safety, and identify potential areas of concern. Material/Methods: Over a 28 months period data was collected prospectively across 14 hospitals in 10 countries for patients receiving re-irradiation to the thorax (including breast and chest wall), abdomen and pelvis. Patients received either type 1 re-irradiation (high- dose re-irradiation ≥ 50 Gy EQD2 with geometrical overlap with the previously irradiated volume) or type 2 re-irradiation (lower doses without overlap but potential side effect concerns) for various primary tumours. There were no restrictions on radiotherapy techniques, surgery or (concomitant) systemic therapies.Only grade 3+ AEs(CTCAE V5.0) were collected. For analysis, patient demographics, tumour and treatment characteristics as well as mortality events were extracted. Results: Between May 2023 and September 2025, 387 patients were included in this analysis, after exclusion of 81 patients (31 screening failures, 50 with missing data), encompassing a total of 465 reirradiation targets. Median follow-up time was 12 months. Median age was 71 years, 45.5% were female and patients had predominantly ECOG PS 0-1 (90%). The primary tumours were prostate (35.5%), lung (25.3%), breast (27.6%), colo-rectal (12.4%), and gynaecological cancers (2.6%). The most commonly treated regions were the thorax (35.4%), pelvis (31.1%), and abdomen (10.1%). The re-irradiated targets comprised locoregional recurrences (48.4%), metastases (24.5%) and second primary tumours (11.0%). Among the metastatic lesions, 89.2% were classified as oligometastatic. Concomitant systemic therapy was administered in 38.2% of patients.In total, 5 patients experienced G3 AEs (table 1) of which 2 were acute (0.5%; dysuria, pneumonitis) and 3 (0.8%; COPD exacerbation, peripheral neuropathy, erectile dysfunction) occurred within the observation period of 12 months. No grade 4 or 5 AEs were observed.
Conclusion: In this early interim analysis, re-irradiation appears feasible and well tolerated in a predominantly fit patient population. Six-month actuarial survival is high, although median survival has not yet been reached. These preliminary findings suggest that patient selection and treatment delivery in this multicentre, real-world cohort are generally safe. Outcome regarding tumour control and progression patterns are awaited and will be reported after longer follow-up. Keywords: reirradiation, prospective, side effects, survival
Digital Poster 3728 Deep hyperthermia and radiotherapy: A promising palliative treatment option for recurrent and treatment-refractory bulky tumours Moritz Neesen 1 , Nicolas Bachmann 1 , Markus Fürstner 2 , Abirramy Varatharajan 1 , Binaya Kumar Shrestha 1 , Hossein Hemmatazad 1 , Attila Kollar 3 , Daniel Matthias Aebersold 1 , Codruta Ionescu 1 , Emanuel Stutz 1 1 Department of Radiation Oncology, Bern University Hospital, University of Bern, Bern, Switzerland. 2 Division of Medical Radiation Physics and Department of Radiation Oncology, Inselspital, Bern University Hospital, Bern, Switzerland. 3 Department of Medical Oncology, Inselspital, Bern University Hospital, Bern, Switzerland Purpose/Objective: Bulky tumours remain therapeutically challenging due to hypoxia-induced resistance to systemic therapy and radiation (RT). This study aims to evaluate the safety and oncologic outcomes of deep radiative
At 6 months post re-irradiation, actuarial survival was
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