BackgroundThe prognostic impact of radiographic duodenal invasion (rDI) of pancreatic ductal adenocarcinoma (PDAC) has yet to be fully elucidated. This retrospective study aimed to investigate the prognostic and clinicopathological significance of rDI in patients with PDAC after pancreatoduodenectomy (PD). Materials and methodsWe retrospectively analyzed 223 consecutive patients with resectable (R) and borderline resectable (BR)-PDAC that underwent up-front PD between 2002 and 2018. rDI was assessed by preoperative multi-detector row computed tomography. ResultsNinety-three (42%) patients with PDAC had rDI, and all of them had pathological DI (pDI). The rDI(+) group had larger tumor size, BR-PDAC was more common, there was higher serum CA19-9 level, and microscopic lymphovascular invasion was more common than in the rDI(−) group. rDI was associated with significant reduction in overall survival (OS) (P < 0.001) and recurrence-free survival (RFS) (P < 0.001). In multivariate analysis, rDI was an independent prognostic factor in OS [hazard ratio (HR) = 0.52; 95% confidence interval (CI) 0.38–0.73, P < 0.001] and RFS [HR = 0.56; 95% CI 0.40–0.78, P = 0.001]. rDI was also an independent risk factor for early recurrence within 12 months [odds ratio (OR) = 0.36; 95% CI 0.18–0.73, P = 0.005]. rDI had positive correlation with liver recurrence (P = 0.024). ConclusionBiological aggressiveness of PDAC with rDI implies short OS and early recurrence with frequent liver metastasis. Aggressive perioperative chemotherapy is recommended to improve prognosis, especially for R-PDAC patients with rDI.