S1126
Clinical – Upper GI
ESTRO 2026
identified. Overall survival (OS), local control (LC), and distant metastasis-free survival (DMFS) were estimated using the Kaplan–Meier method. Side-effects were graded according to the Common Terminology Criteria for Adverse Events (CTCAE v5). Results: A total of 116 patients were included. Median age was 72 years (range 46–90), and 84% had ECOG 0–1. Disease stages included locally advanced PDAC (LAPC; 47%), borderline resectable PDAC (BRPC; 6%), isolated local relapse (ILR; 32%), and medically inoperable patients (17%). Median CA19-9 levels were 199 U/mL (range 1–7621) at diagnosis and 83.8 U/mL (range 2– 3000) immediately before MRIgRT.Induction chemotherapy was administered to 62% of patients for a median of five months, mainly FOLFIRINOX (53%) or gemcitabine/nab-paclitaxel (33%). MRIgRT was delivered with a median dose of 40 Gy (range 33–50 Gy) in five fractions, mostly on consecutive days (86%), corresponding to a median biologically effective dose (BED10) of 72 Gy. Median follow-up was 16 months from diagnosis and 10 months from MRIgRT.One- and two-year LC rates were 80% and 62%. Median OS from diagnosis was 21 months (1- and 2-year OS: 89% and 34%), and 13 months from MRgRT (1- and 2-year OS: 52% and 21%). Median DMFS was five months. Stage- specific median OS was 13 months for LAPC/BRPC, 15 months for ILR, and 9 months for medically inoperable cases.Two patients (2%) experienced acute grade 3 side-effects (cholangitis, duodenal stricture). Six patients (5%) developed grade 3 side-effects possibly related to MRIgRT (weight loss, recurrent biliary tract infections, biliary stenosis, duodenal hemorrhage). No late grade >3 side-effects were observed. Conclusion: This large European experience shows that MRIgRT can be delivered safely with reasonable LC and OS in inoperable PDAC. The results strengthen the growing evidence that MRgRT may enhance long-term outcomes in this setting, warranting confirmation in prospective trials.
Keywords: MRgRT, PDAC, MR-Linac
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