Examining neoadjuvant treatment candidates in resectable pancreatic cancer based on tumor-vessel interactions and CA 19-9 levels: A retrospective cohort study

Introduction: The applicability of neoadjuvant treatment (NAT) for resectable pancreatic ductal adenocarcinoma (PDAC) has arisen, however, high-level evidence is lacking. This study aimed to explore patient subgroups with high-risk resectable PDAC for selecting candidates who may benefit from NAT. Methods: The 1,132 patients with resectable or borderline resectable PDAC who underwent surgery between 2007 and 2021 were retrospectively reviewed. Patients with resectable PDAC without contact of major vessels (R-no contact) (n=651), with contact of portal vein or superior mesenteric vein (PV/SMV) ≤180° (R-contact) (n=306), and borderline resectable PDAC without arterial involvement (BR-V) (n=175) were analyzed. Results: The mean age was 64.3 ± 9.8 years, and 647 patients (57.2%) were male. The median follow-up was 26 months in the entire cohort. Patients with resectable PDAC without vascular contact had the most improved overall survival (OS) (median; 31.5 months). OS did not significantly differ between NAT and upfront surgery in the entire resectable PDAC cohort. However, in R-contact group, NAT showed significantly improved OS compared to upfront surgery (33 vs. 23 months). Neoadjuvant FOLFIRINOX was showed a better OS than gemcitabine-based regimens in patients who underwent NAT (34 vs. 24 months). NAT was associated with a better survival in the patients with CA 19-9 level ≥150 U/mL, only when the tumor has PV/SMV contact in resectable disease (40 vs. 19 months, P = 0.001). Conclusions: NAT can be considered as an effective treatment in patients with resectable PDAC, particularly when the tumor is in contact with PV/SMV and CA 19-9 ≥150 U/mL.