Key preoperative findings for predicting vascular invasion and recurrence after conversion surgery after chemotherapy in pancreatic cancer

Background Pancreatic cancer has poor outcomes, with vascular invasion being a critical factor in determining resectability and prognosis. Accurate assessment of vascular invasion remains challenging. Purpose To investigate the predictors of vascular invasion and recurrence-free survival (RFS) in patients with pancreatic cancer undergoing surgery after chemotherapy using computed tomography (CT) and histopathological data, and to evaluate the diagnostic performance of CT-based vascular scoring system. Material and Methods We retrospectively analyzed 98 patients with pancreatic cancer showing vascular encasement on CT who underwent chemotherapy before surgery. Two reviewers evaluated baseline and preoperative CT to assess resectability. Clinicohistopathological factors were assessed. RFS was analyzed using the Kaplan–Meier method. The predictors were identified using Cox proportional hazards and logistic regression models. A 3-point scoring system quantified vascular involvement at baseline and preoperative CT, with total scores combining both time points. Results Of the 98 patients, 32 (32.7%) had pathologically confirmed vascular invasion. Change in tumor size (odds ratio [OR]=3.1; P = 0.022), T stage (OR=15.4; P = 0.038), and perineural invasion (OR=13.2; P = 0.028) predicted vascular invasion. Total vascular scores strongly correlated with vascular invasion (areas under the curve=0.924 and 0.803). Median RFS was 21 months, influenced by lymph node involvement at baseline and preoperative CT (hazard ratio [HR]=2.3; P = 0.009 and HR=2.6; P = 0.013, respectively), tumor differentiation (HR=3.3; P = 0.047), and elevated CA 19–9 (HR=2.8; P = 0.019). Conclusion Changes in tumor size on CT, T stage, and perineural invasion predict vascular invasion. In addition, a CT-based scoring systems can accurately predict vascular invasion after chemotherapy.