Diagnostic and Prognostic Role of 18-FDG PET/CT in the Management of Resectable Biliary Tract Cancer.

OBJECTIVES: Role of 18-FDG PET/CT had been well established in other more prevalent malignancies such as colorectal and lung cancer; however, this is not as well defined in cholangiocarcinoma. Literature focusing on the prognostic values of preoperative PET/CT for resectable cholangiocarcinoma is scarce.

METHOD: This is a retrospective cohort of 66 consecutive patients who had received curative resection for cholangiocarcinoma from 2010 to 2015. All patients had preoperative 18-FDG PET/CT performed. Accuracy of metastatic lymph node detection of PET/CT and the prognostic value of maximum standard uptake value (SUV-max) was explored.

RESULTS: There were 38 male and 28 female recruited, and the median age was 66. Intrahepatic cholangiocarcinoma (ICC) constituted the majority (59.1%) of the cases, followed by hilar cholangiocarcinoma (22.8%), gallbladder cancer (13.6%) and common bile duct cancer (4.5%). The 3-year disease-free survival (DFS) and overall survival (OS) of the whole population were 27.1 and 39.2%, respectively. The median follow-up duration was 27 months. The accuracy of PET/CT in metastatic lymph node detection was 72.7% (P = 0.005, 95% CI 0.583-0.871) and 81.8% (P = 0.011, 95% CI 0.635-0.990) in whole population and ICC subgroup analysis, respectively. SUV-max was shown by multivariate analysis to be an independent factor for DFS (P = 0.007 OR 1.16, 95% CI 1.04-1.29) and OS (P = 0.012 OR 1.145, 95% CI 1.030-1.273) after resection. SUV-max of 8 was shown to be a discriminant cut-off for poor oncological outcomes in patients with early cholangiocarcinoma (TNM stage I or II) after curative resection (3-year DFS: 21.2 vs. 63.2%, P = 0.004, and 3-year OS: 29 vs. 74% P = 0.048, respectively).

CONCLUSION: PET/CT is a reliable imaging modality for metastatic lymph node detection in cholangiocarcinoma. Tumour SUV-max is an independent factor for oncological outcomes in patients with resectable disease. For patients who have TNM stage I or II cholangiocarcinoma, tumour SUV-max over 8 is associated with significantly inferior disease-free and overall survival even after curative resection.