Preoperative Risk Classification for Early Recurrence After Curative-Intent Resection of Perihilar Cholangiocarcinoma: A Single-Center Retrospective Study

Background/Objectives: Early recurrence (ER) after curative-intent resection of perihilar cholangiocarcinoma (PHC) is associated with poor prognosis. However, simple preoperative predictors remain insufficiently defined. This study aimed to identify preoperative factors associated with ER and explore a risk classification. Methods: We retrospectively analyzed 108 patients who underwent curative-intent resection for PHC at a single institution between 2007 and 2023. ER was defined as recurrence within 1 year after surgery. Cox proportional hazards regression was used to identify associated factors. Results: ER occurred in 24 patients (22.2%). Multivariable analysis identified younger age (hazard ratio [HR] = 0.942), higher carcinoembryonic antigen (CEA; HR = 1.115), higher carbohydrate antigen 19-9 (CA19-9; HR = 1.001), and higher neutrophil-to-lymphocyte ratio (NLR; HR = 1.404) as factors associated with ER. In an exploratory classification, one point was assigned for age < 61 years, CEA ≥ 5.4 ng/mL, CA19-9 ≥ 89.4 U/mL, and NLR ≥ 2.037. Among 105 patients with complete data, the estimated 1-year recurrence rate was 70.0% in patients with 3–4 points (n = 10), versus 17.4% in those with 0–2 points (n = 95; p < 0.001). Bootstrap analysis suggested optimism in the score’s apparent discrimination when cutoff optimization was considered (optimism-corrected C-index, 0.668). Conclusions: Age, CEA, CA19-9, and NLR were associated with ER after PHC resection. The exploratory classification requires external validation before clinical use.