Neoadjuvant SBRT and intraoperative electron radiotherapy in pancreatic cancer resection.

BACKGROUND/OBJECTIVES: Pancreatic cancer surgery frequently results in positive margins and local recurrence despite multimodal treatment. This study evaluated whether combining neoadjuvant stereotactic body radiotherapy (SBRT) with intraoperative electron radiotherapy (IOeRT) during resection could improve local control and surgical outcomes. METHODS: A retrospective analysis was performed on 15 patients with resectable or borderline resectable pancreatic adenocarcinoma treated between 2021 and 2023. All patients received image-guided, motion-managed SBRT (35-40 Gy/5 fractions to PTV_high; 25 Gy/5 fractions to PTV_low) followed by surgical resection and IOeRT (median 10 Gy; 12 Gy when margins were at risk). Toxicities were graded by CTCAE v5.0 and postoperative complications by Clavien-Dindo criteria. Follow-up included imaging and CA 19-9 every 3 months. Survival was estimated using Kaplan-Meier analysis. RESULTS: Mean patient age was 66 years; 60% had tumors in the pancreatic body and 40% in the head. Two-thirds were borderline resectable and received neoadjuvant chemotherapy. Margin-negative resection was achieved in 86.7%, including two complete pathologic responses in BRCA2-mutated tumors. Median overall and progression-free survival were 30 and 16 months, respectively. One patient (6.7%) developed isolated local recurrence, while distant metastases occurred in over half. Toxicities were mainly grade 1-2 fatigue, nausea, or pain; surgical complications were grade 1-2 in 53%, grade 3 in 7%, and grade 5 in 7%. CONCLUSIONS: Neoadjuvant SBRT with IOeRT during pancreatic cancer resection is feasible, achieves high rates of negative margins, and provides promising local control. Distant progression remains the dominant mode of failure.