A Single-Center Analysis of 30- and 90-Day Post-Pancreatectomy Complications in Patients Undergoing Neoadjuvant Radiation with EBRT Versus MRI-guided SBRT.

572 Background: Stereotactic MRI -guided adaptive radiation therapy (SMART) is being investigated for enhanced efficacy in locally advanced, borderline resectable and medically inoperable pancreatic cancer. Traditionally, conventionally fractioned chemoradiation (EBRT) has been used for operable patients. We sought to evaluate whether there would be differences in surgical complications and outcomes in the 30- and 90- day postoperative period in patients who received either neoadjuvant EBRT or SMART followed by definitive surgery. Methods: A retrospective single-center analysis of patients with either resectable, borderline resectable or locally advanced tumors of the pancreas or duodenum, treated with neoadjuvant radiation and surgical management between 2014 and 2021 was performed. Patient demographics and post-surgical complications were collected and stratified according to both treatment arms. The International Study Group of Pancreatic Surgery (ISGPS) classifications were used to define and grade postoperative pancreatic fistula (POPF), delayed gastric emptying (DGE) and postpancreatectomy hemorrhage (PPH). A univariate analysis was done followed by a multivariate analysis. Results: Among the 65 patients (mean age 62.6 years, 46% female) who underwent definitive surgical intervention, 44 (67.7%) received EBRT, and 21 (32.3%) received SMART. Baseline characteristics including age, sex, race, ASA, and Charlson comorbidity index (CCI) scores were found to be similar. On univariate analysis, PPH was significantly higher in SMART (OR, 6.6; 95% CI, 1.2 to 37.3; p = 0.034). After adjusting for confounders on multivariate analysis, it appears there is a trend towards higher PPH in the SMART cohort ( p = 0.052). Conclusions: Neoadjuvant SMART followed by definitive surgery is not associated with worse outcomes in the 30- and 90- day postoperative period vs. neoadjuvant EBRT. Although there was a trend towards PPH on multivariate analysis, further discussion is warranted involving vascular resection, vascular stents and anticoagulation.[Table: see text]