PO11 | THROMBOEMBOLIC EVENTS DURING PERIOPERATIVE THERAPY FOR RESECTABLE AND BORDERLINE RESECTABLE PANCREATIC CANCER IN THE PREOPANC-2 TRIAL

Introduction. Pancreatic ductal adenocarcinoma (PDAC) is associated with a high risk of venous thromboembolism (VTE), which is burdensome and associated with decreased survival. While neoadjuvant treatment is increasingly used in patients with PDAC, data on VTE in this setting remain scarce. Aim. This study evaluated VTE incidence during (neo)adjuvant therapy for resectable and borderline resectable PDAC and its relation to survival. Methods. This study included patients from the investigator-initiated, multicenter, randomized controlled phase 3 PREOPANC-2 trial. Patients were randomized to neoadjuvant FOLFIRINOX followed by surgery (FFX arm) or neoadjuvant gemcitabine-based chemoradiotherapy, followed by surgery and adjuvant gemcitabine (CRT arm). VTE was defined as both incidental and symptomatic lower or upper extremity deep-vein thrombosis, pulmonary embolism (PE), splanchnic vein thrombosis, and catheter-related thrombosis. VTE occurrence was retrospectively evaluated from randomization to 12 months post-randomization. The association with overall survival (OS) was analyzed using Cox regression analysis. Results. VTE was diagnosed in 28 of 325 patients (9%): 9 (3%) preoperatively and 19 (8%) postoperatively. Most VTEs were symptomatic (54%). Although a higher proportion of patients developed postoperative VTE in the CRT arm (FFX 3% vs CRT 12%, p=0.02), the 12-month cumulative incidence did not differ between arms (6% vs. 11%, p=0.06). Two patients died from PE-related causes in the CRT arm. VTE was independently associated with reduced OS (adjusted time-varying HR 2.13, p=0.002). Conclusions. VTE occurred in 9% of patients with (borderline) resectable PDAC undergoing (neo)adjuvant treatment in the year post-randomization and was associated with decreased OS. These results underscore the need for standardized reporting of thromboembolic events in clinical trials and future studies assessing the potential benefits of thromboprophylaxis during neoadjuvant therapy.