Defining the optimal bilirubin level before hepatectomy for hilar cholangiocarcinoma

BACKGROUND: In the management of operable hilar cholangiocarcinoma (HC) patients with hyperbilirubinemia, preoperative biliary drainage is a measure to bring down the bilirubin to a certain level so as to avoid adverse postoperative outcomes that would otherwise result from hyperbilirubinemia. A cutoff value of bilirubin level in this context is needed but has not been agreed upon without controversy. This retrospective study aimed to identify a cutoff of preoperative bilirubin level that would minimize postoperative morbidity and mortality. METHODS: Data of patients having hepatectomy with curative intent for HC were analyzed. Discriminative analysis was performed to identify the preoperative bilirubin level that would make a survival difference. The identified level was used as the cutoff to divide patients into two groups. The groups were compared. RESULTS: Ninety patients received hepatectomy with curative intent for HC. Their median preoperative bilirubin level was 23 μmol/L. A cutoff preoperative bilirubin level of 75 μmol/L was derived from Youden’s index (sensitivity 0.333; specificity 0.949) and confirmed to be optimal by logistic regression (relative risk 9.250; 95% confidence interval 1.932–44.291; p = 0.005), with mortality shown to be statistically different at 90 days (p = 0.008). Patients were divided into Group A (≤75 μmol/L; n = 82) and Group B (> 75 μmol/L; n = 8). Group B had a higher preoperative bilirubin level (p < 0.001), more intraoperative blood loss (3.12 vs 1.4 L; p = 0.008), transfusion (100% vs 42.0%; p = 0.011) and replacement (2.45 vs 0.0 L; p < 0.001), more postoperative renal complications (p = 0.036), more in-hospital deaths (50% vs 8.5%; p = 0.004), and more 90-day deaths (50% vs 9.8%; p = 0.008). Group A had a longer follow-up period (p = 0.008). The groups were otherwise comparable. Disease-free survival was similar between groups (p = 0.142) but overall survival was better in Group A (5-year, 25.2% vs 0%; p < 0.001). On multivariate analysis, preoperative bilirubin level and intraoperative blood replacement were risk factors for 90-day mortality. CONCLUSION: A cutoff value of preoperative bilirubin level of 75 μmol/L is suggested, as the study showed that a preoperative bilirubin level ≤ 75 μmol/L resulted in significantly less blood replacement necessitated by blood loss during operation and significantly better patient survival after surgery.