AbstractBackgroundLymph node metastasis (LNM) is associated with poor prognosis in patients with duodenal cancer (DC). However, the efficacy and optimal extent of lymph node (LN) dissection have not been thoroughly discussed.MethodsA total of 98 consecutive patients with DC who underwent surgical resection (pancreatoduodenectomy, n = 55; partial resection, n = 32; pancreas‐sparing total duodenectomy, n = 9) were retrospectively analyzed. The LN stations located upstream of the lymphatic flow were defined as Np stations according to tumor location, whereas the others were defined as Nd stations. The association between the dissection of each LN station and survival outcome was investigated using the efficacy index (EI; percentage of metastases to lymph nodes in each station multiplied by the 5‐year survival rate of metastatic cases).ResultsThe survival of patients with LNM at the Nd stations (n = 6) was significantly worse than that of patients with LNM only at the Np stations (n = 20) (relapse‐free survival, median survival time [MST], 6.0 vs. 48.4 months, p < 0.001; overall survival, MST, 15.1 vs. 96.0 months, p < 0.001). Multivariate analysis identified LNM at Nd stations as an independent prognostic factor for overall survival (hazard ratio 9.92; p = 0.015). The Np stations had a high EI (range, 8.34–20.88), whereas the Nd stations had an EI of 0, regardless of the tumor location.ConclusionsLN dissection of the Np stations contributed to acceptable survival, whereas LNM of the Nd stations led to poor survival, possibly reflecting advanced tumor progression to systemic disease in patients with DC.