Intraoperative Paraaortic Lymph Node Sampling to Guide Surgical Decision-Making in Perihilar Cholangiocarcinoma.

BACKGROUND: Preoperative diagnosis of paraaortic lymph node (PALN) metastasis in patients with perihilar cholangiocarcinoma (PHC) remains challenging. This study aimed to evaluate the incidence, prognostic impact, and clinical role of intraoperative PALN sampling in patients with potentially resectable PHC. PATIENTS AND METHODS: We retrospectively analyzed 143 patients with PHC who underwent intraoperative PALN sampling at our institution between April 2008 and March 2021. We evaluated the incidence of PALN metastasis and its impact on long-term outcomes. RESULTS: PALN metastasis was identified in 17 patients (11.9%). Preoperative imaging showed limited sensitivity for detecting PALN metastasis, with positron emission tomography-computed tomography (PET-CT) identifying only 17.6% of patients positive for PALN. Overall survival was significantly worse in the PALN-positive group than in the PALN-negative group (median survival time: 18.0 versus 45.4 months, p < 0.001). Survival analysis demonstrated a stepwise worsening prognosis from no lymph node metastasis to regional lymph node metastasis and PALN metastasis, with median survival times of 91.4, 24.7, and 18.0 months, respectively. Among patients positive for PALN, no significant survival difference was observed between those who underwent resection and those who did not (15.6 versus 18.0 months, p = 0.790). CONCLUSIONS: Intraoperative PALN sampling is clinically useful in patients with PHC because it facilitates accurate intraoperative staging and individualized surgical decision-making by helping identify patients who are unlikely to benefit from immediate upfront resection.