Survival outcomes in localized pancreatic cancer treated with neoadjuvant chemotherapy (NAC).

683 Background: There is uncertainty about whether chemotherapy administered perioperatively or only in the adjuvant setting leads to the best survival outcomes in localized pancreatic cancer. Our tertiary care university-based practice favors NAC for the majority of eligible patients (pts). We performed a retrospective analysis to analyze outcomes in pts with resectable (R) and borderline resectable (BR) disease, and present analysis of overall survival (OS) and disease-free survival (DFS). Methods: Surgical candidates with R and BR pancreatic adenocarcinoma who were candidates for treatment from 2017-2023 were included. Resectability was determined by standard criteria and multi-disciplinary tumor board. OS and DFS were calculated using Kaplan-Meier analysis and log-rank tests. Results: 91 pts were included and started on NAC, 44 with resectable and 47 with BR disease. 56 pts underwent surgery while 35 (13 R, 22 BR) did not undergo surgery due to progression of disease, decline in functional status, or pt decision. Those that did not undergo surgery had a significantly worse DFS of 7 months compared to 18 months for those who underwent resection (p=<0.01). Pts with resectable disease had significantly better DFS and OS compared to those with BR disease where DFS was 17 months (95% CI 10.7-23.3) versus 11 months (95% CI 8.9-13.1) and OS was 30 months (95% CI 23.0-42.1) versus 16 months (95% CI 14.2-24.3), p=0.02 and p=0.002 for DFS and OS respectively. 33 patients received NAC with mFOLFIRINOX and 49 received gemcitabine/nab-paclitaxel. There was no significant difference in DFS or OS between patients who received NAC with mFOLFIRINOX or gemcitabine/nab-paclitaxel. With mFOLFIRINOX median DFS was 13 months (95% CI 7.7-18.3) and median OS 29 months (19.0-37.0) while with gemcitabine/nab-paclitaxel median DFS was 13 months (8.7-17.3) and median OS was 23 months (95% CI 14.5-29.8) (DFS p=0.69, OS p=0.36). Conclusions: In our single center retrospective review of patients with resectable or borderline resectable pancreatic adenocarcinoma planned for NAC and surgery, whether tumors were resectable or borderline resectable was associated with significantly better DFS and OS while choice of chemotherapy between mFOLFIRINOX or gemcitabine/nab-paclitaxel did not significantly affect survival outcomes. Despite 38% of pts not proceeding to surgery, survival outcomes were comparable to real world adjuvant studies in similar populations.