Value of 18F-FDG PET/CT in preoperative diagnosing and staging of extrahepatic cholangiocarcinoma

Abstract

Objective To evaluate the value of 18F-FDG PET/CT in preoperative diagnosis and staging of suspected extrahepatic cholangiocarcinoma (EHCC). Methods The clinical data of 116 patients (72 males, 44 females; age range 26-89 years) with suspected EHCC from January 2013 to October 2014 were retrospectively analyzed. All patients received preoperative whole body 18F-FDG PET/CT scan. The imaging results were compared with final clinical diagnosis. The diagnostic sensitivity, specificity, positive predictive value, negative predictive value and accuracy of 18F-FDG PET/CT were calculated. Two-sample t test was applied to compare lesion SUVmax of malignant and benign diseases. One-way analysis of variance was applied to compare SUVmax of highly, moderately and poorly differentiated tumors. χ2 test was used to compare the difference of diagnostic sensitivities for hilar cholangiocarcinomas and common bile duct tumors. Results All patients were confirmed by exploratory laparotomy and subsequent histologic examination. A total of 94 cases (93 adenocarcinomas and 1 squamous carcinoma) were confirmed malignant and 22 cases (11 biliary calculi, 9 cholangitis, 1 choledochal cyst, 1 tuberculosis) were confirmed benign. The diagnostic sensitivity, specificity, positive predictive value, negative predictive value and accuracy of 18F-FDG PET/CT for primary tumor were 61.7%(58/94), 77.3%(17/22), 92.1%(58/63), 32.1%(17/53), 64.7%(75/116), respectively. The diagnostic sensitivity and specificity for regional lymph node metastasis were 45.5%(15/33), 91.4%(53/58), and those for distant metastasis were 3/4, 94.3%(82/87). The SUVmax of malignant tumors were higher than that of benign lesions (4.57±3.75, 2.72±2.48; t=2.83, P 0.05). 18F-FDG PET/CT showed a lower sensitivity in hilar cholangiocarcinomas than that in common bile duct tumors, while no statistical significance was observed: 48.6% (17/35) vs 69.0% (40/58), χ2=3.827, P>0.05. Conclusions The value of 18F-FDG PET/CT in preoperative diagnosis and staging of EHCC is limited. It can distinguish some benign diseases from malignant tumors, but with higher false positive for cholangitis. It can help to adjust treatment strategies by detecting distant metastasis. Key words: Cholangiocarcinoma; Diagnosis; Neoplasm staging; Positron-emission tomography; Tomography, X-ray computed; Deoxyglucose