Total lesion glycolysis by 18F-fluorodeoxyglucose positron emission tomography predicts tumor aggressiveness in patients with extrahepatic bile duct carcinoma

Background: F-18- fluorodeoxyglucose positron emission tomography/computed tomography ((FF)-F-18- FDG- PET/CT) parameters are prognostic factors in multiple malignancies. However, the prognostic value in bile duct carcinoma is unclear. We evaluated the impact of metabolic parameters of (FF)-F-18- FDG- PET/CT in resect-able extrahepatic bile duct carcinoma. Methods: We retrospectively reviewed the records of 100 patients with extrahe-patic bile duct carcinoma who had undergone (FF)-F-18- FDG- PET/CT and subsequent surgical resection between January 2017 and January 2023. We calculated maxi-mum standardized uptake value (SUVmax), metabolic tumor volume (MTV), and total lesion glycolysis (TLG) and investigated their prognostic significance. Results: The optimal cutoff values of SUVmax, MTV, and TLG for predicting overall survival (OS) after surgery were 3.88, 3.55 and 7.55, respectively. In mul-tivariate analysis, each metabolic parameter influenced both OS and recurrence- free survival (RFS). TLG showed the lowest Akaike information criteria statistic value, indicating that it had the best ability to predict OS and RFS. High TLG was significantly associated with the number of lymph node metastases and poorly differentiated type. Patients with high TLG showed poorer RFS and OS, which were significantly worse than in those with low TLG. Conclusions: Tumor TLG predicted tumor malignancy potential and could be a useful prognostic predictor for extrahepatic bile duct carcinoma.