Effect on local control and survival of electron beam intraoperative irradiation for resectable pancreatic adenocarcinoma

Purpose: To assess the impact on local control and survival of intraoperative radiotherapy (IORT) in resectable pancreatic adenocarcinoma. Methods and Materials: The outcome of 127 patients surgically treated with curative intent combined with IORT was compared with the therapeutic results of 76 patients treated with surgery as exclusive treatment. Results: Operative mortality and morbidity were similar in IORT and no-IORT patients. In 49 patients with locally limited disease (Stage I-II; LLD), IORT (n=30) reduced the local failure rate and significantly prolonged time to local failure (TTLF), time to failure (TTF), and overall survival (OS) with respect to surgery alone (n=19). The multivariate analyses, stratifying patients by age, tumor grade, resection margins, chemotherapy, and external-beam radiotherapy use, confirmed the independent impact of IORT on outcome. In patients with locally advanced disease (Stage III-IVA; LAD), IORT had an impact on local failure rate and on TTLF when combined with beam energies of greater than 6 MeV, whereas no effect on TTF and OS was observed. Conclusion: IORT did not increase operative mortality and morbidity and achieved a significant improvement in local control and outcome in patients with LLD. In patients with LAD, beam energies greater than 6 MeV prolonged TTLF