S2624
Radiobiology - Translational radiobiology
ESTRO 2026
Digital Poster 4377
platform (SARRP), were determined in PC3 and VCaP human xenografts. Results: AuX2R possessed excellent colloidal stability under physiological conditions. Hyperspectral imaging demonstrated rapid uptake compared to PEG- stabilised AuNPs, with ICP-AAS confirming >400-fold increased accumulation in multiple tumour cell models. Additionally, AuX2R showed robust target specificity, potently abrogating IL-8 signalling. AuX2R enhanced RT response by >30% in vitro, increasing 53BP1 DSB lesions by >20%, an effect retained over 24 h post radiation. In vivo, AuX2R was maximally retained in the tumour with >60% injected dose detectable 21 days post IT administration. Furthermore, AuX2R had no significant impact on serum biochemistry or systemic innate and adaptive immune responses. In preclinical models of PCa, a single IT administration of AuX2R radically boosted the anti-tumour efficacy of both RT (p>0.0001) and SBRT (p>0.0001). While RT-alone delayed tumour doubling from ~10 days to ~30 days, the addition of AuX2R robustly attenuated tumour growth, further delaying tumour doubling (>55 days). Conclusion: AuX2R represents an innovative multimodal approach to enhancing prostate tumour radiation sensitivity, integrating physical dose enhancement with targeted inhibition of pro-inflammatory IL-8 signalling. Given its favourable biocompatibility profile, high tumour retention and potent radiosensitising efficacy, AuX2R is ideally positioned as a novel and promising candidate for clinical translation in precision
Identification of immune biomarkers for survival prediction in patients with small cell lung cancer (SCLC) treated with concurrent chemoradiation Rianne D.W. Vaes 1 , Iris E.W.G. Laven 1 , Tessa T.J. Welbers 1 , Ruud Houben 1 , Juliette Degens 2 , Lizza E.L. Hendriks 3 , Dirk De Ruysscher 1 1 Department of Radiation Oncology (Maastro Clinic), GROW Research Institute for Oncology and Reproduction, Maastricht University Medical Center+, Maastricht, Netherlands. 2 Department of Pulmonary Diseases, Zuyderland Medical Center, Geleen, Netherlands. 3 Department of Pulmonary Diseases, GROW Research Institute for Oncology and Reproduction, Maastricht University Medical Center+, Maastricht, Netherlands Purpose/Objective: Till 2025, the current standard of care for patients with limited stage small cell lung cancer (SCLC) is concurrent chemoradiotherapy (cCRT). Although SCLC initially respond well to chemotherapy and is sensitive to radiotherapy, due to early treatment resistance, about 30% of the patients treated with cCRT die within 1 year after treatment initiation. Both chemotherapy and radiotherapy are known to affect the immune status which is expected to be highly variable among each patient, influencing treatment outcomes. Immunological biomarkers to assess the actual immune status before the start of treatment are still lacking. We aimed to identify peripheral immunological biomarkers that can identify patients who are at high risk of early mortality during and after cCRT. Material/Methods: Patients with pathological confirmed limited stage SCLC treated with curative intent cCRT were included (Maastro biobank, 2006-2019, NCT01084785). Clinical- and standard diagnostic parameters included age, gender, BMI, performance status (PS), tumor stage (staging recoded to TNM8 for all patients), CRP, albumin, sodium, and LDH. EDTA-plasma concentrations of GM-CSF, IFN- α 2a, IFN- β , IFN-y, IL-1 α , IL-1 β , IL-2, IL-6, IL-8, SDF-1a, IL-10, IL-12p70, IP-10, IP- 10, MCP1, PD-L1, TNF- α , and RANTES were analyzed using the U-plex assay (MesoScaleDiscovery). For each analyte, optimal cut-off points for OS were based on max Log-Rank statistics. OS was calculated from start RT. High risk of early mortality was defined as death within one year after the first fraction of RT. Results: A total of 89 patients were included. Mean age was 64.6 (±8.4) years, 56.2% were male, and median OS was 21.0 months (95%CI: 14.8-27.2). Univariate Cox regression analyses only identified the clinical variable tumor stage IIIC (HR=3.8, 95%CI: 1.0-14.9, p=0.05) as
radiotherapy. References: 1. Dearnaley, D. et al. Conventional versus
hypofractionated high-dose intensity-modulated radiotherapy for prostate cancer: 5-year outcomes of the randomised, non-inferiority, phase 3 CHHiP trial. Lancet Oncol (2016)2.Tree, AC. et al. Intensity- modulated moderately hypofractionated radiotherapy versus stereotactic body radiotherapy for prostate cancer (PACE-C): early toxicity results from a randomised, open-label, phase 3, non-inferiority trial. Lancet Oncol (2025)3. Bonvalot, S. et al. NBTXR3, a first-in-class radioenhancer hafnium oxide nanoparticle, plus radiotherapy versus radiotherapy alone in patients with locally advanced soft-tissue sarcoma (Act.In.Sarc): a multicentre, phase 2-3, randomised, controlled trial. Lancet Oncol (2019) Keywords: Prostate cancer, gold nanoparticles, chemokines
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