Surveillance method and imaging characteristics of recurrent biliary cancer after surgical resection

This is a review of the diagnostic imaging techniques and findings of recurrent biliary cancer after surgical resection of the extrahepatic bile duct and gallbladder. Radiological examination plays an important role in diagnosing postoperative recurrence of biliary cancers. Early detection and diagnosis of recurrent cancer is critical in obtaining proper treatment and improves the prognosis. In the surveillance of recurrent biliary cancer, several diagnostic imaging modalities are currently used. Usually CT is the most common method for surveillance of postoperative patients, but MRI and PET/CT scans are also widely used. Recurrent biliary cancer can manifest as local recurrence, liver metastasis, lymph node metastasis, and peritoneal metastasis. Imaging findings of a locally recurrent tumor or metastatic lymph node enlargement overlaps with benign postoperative changes, thus radiologists commonly overlook subtle CT findings or misinterpret them as benign postoperative changes. There are several reports that FDG-PET scan is more effective in the diagnosis of recurrent biliary tract cancer than CT. Multidisciplinary diagnostic approaches using CT, MRI, and FDG-PET as well as clinical information seem to be essential for the precise diagnosis of recurrent tumors.