ESTRO 2025 - Abstract Book

S1745

Clinical – Upper GI

ESTRO 2025

Material/Methods: We retrospectively analyzed 164 patients with LAPC treated with induction chemotherapy (FOLFIRINOX or gemcitabine) followed by (C-)RT across five academic cancer centers between 2011 and 2020. Primary endpoint was overall survival (OS), and secondary endpoints included progression-free survival (PFS), local recurrence (LR), distant metastases (DM), surgical conversion rate, and treatment-related toxicities. We performed multivariate analysis to identify prognostic factors following the treatment. Results: Median OS reached 20.2 months and median PFS was 13.3 months. Two-year OS and PFS rates were 33.0% and 12.1%, respectively. Local and distant control remained challenging, with LR and DM rates of 42.7% and 65.2% at 2 years. Notably, 11.6% of patients initially deemed unresectable achieved surgical conversion following (C-)RT, with 68.4% achieving R0 resection. Surgical conversion was significantly associated with improved OS and PFS (p<0.001 and p=0.01, respectively). Interestingly, oncological outcomes were comparable between FOLFIRINOX and gemcitabine induction regimens. Neither radiological response (RECIST criteria) nor biological response (CA19-9) to induction chemotherapy predicted survival outcomes. Treatment was well-tolerated, with no grade 4 toxicities and minimal grade 3 adverse events.