Bilan d’extension en TEP/TDM au 18F-FDG des cholangiocarcinomes intrahépatiques localement avancés avant radioembolisation en première ligne

Abstract

Intrahepatic cholangiocarcinoma are rare biliary malignancies frequently diagnosed at non-surgical advanced stage with limited efficiency of systemic therapies. Intra-arterial therapies have become a palliative treatment in highly development for unresectable forms in the absence of metastasis, optionally in combination with systemic chemotherapy. A precise staging is essential for pre-interventional tumor targeting and to exclude extrahepatic localization. This study evaluates the 18F-FDG PET-CT in pre-radioembolization staging of advanced intrahepatic cholangiocarcinoma unresectable in first line. Twenty-one patients with intrahepatic cholangiocarcinoma confirmed histologically were included retrospectively. All patients underwent PET-CT and CT scan within an average of 3.6 days. An analysis was conducted by lesion, by lobe, by segment and according to the localization in liver, lymph node or remotely. The sensitivity of primary tumor PET detection was 0,9 without significant difference with CT but the combination of the two methods could detect all hepatic lesions. Lymph node specificity, positive predictive value and accuracy seemed to be better in PET than CT without any possible statistical comparison. PET detected all distant metastases with best performance allowing avoiding unnecessary targeted therapy in 25 % of cases. All lesions analysis (liver, lymph nodes and remote) found a significantly higher accuracy of PET over CT (0.9 vs 0.58, respectively; P<0.0001). This preliminary study shows the value of PET-CT in pre-radioembolization staging with an excellent sensitivity, complementary to CT, and a lymph node specificity and overall performance detection of remotely metastases overpassing conventional imaging.