Usefulness of FDG PET/CT derived parameters in prediction of histopathological finding during the surgery in patients with pancreatic adenocarcinoma

PURPOSE: Pancreatic cancer is the 4th most common cause of cancer death in Japan and exhibits a 5-year overall survival rate of approximately 7%. The accurate diagnosis of pancreatic cancer is important for determining the optimal management strategy. Fludeoxyglucose-positron emission tomography (FDG PET) integrated with computed tomography ((18)F-FDG PET/CT) has emerged as a powerful imaging tool for detecting and evaluating various cancers, and it is used for staging, detecting local recurrence and distant metastasis, measuring therapeutic effects, and predicting prognosis in pancreatic cancer patients. Lately, FDG PET/CT-derived parameters, such as standardized uptake values (SUV), the metabolic tumor volume (MTV), and total lesion glycolysis (TLG), have been suggested as prognostic factors for various types of cancer, including pancreatic cancer. However, there is no consensus regarding the best parameters for evaluating patient prognosis, operability, etc. The purpose of this study was to examine the differences between operable and non-operable pancreatic cancer using FDG PET/CT-derived parameters, and to investigate whether volumetric parameters (TLG and the MTV) are superior to SUV-based parameters for predicting infiltration status/determining operability. MATERIALS AND METHODS: We conducted a retrospective study of the cases of 48 patients with clinically proven pancreatic adenocarcinoma, who underwent FDG PET/CT imaging before treatment. In the operable group, the surgical specimens were subjected to histopathological examinations, and the cases were separated into those exhibiting less and greater infiltration. SUVmax, SUVpeak, the tumor background ratio (TBR), TLG, and the MTV were compared between these groups as well as between the operable and non-operable groups. RESULTS: Venous infiltration showed significant associations with several metabolic parameters (SUVmax, SUVpeak, and the TBR). However, it did not display any significant associations with volumetric parameters, such as TLG or the MTV. None of the FDG PET/CT-derived parameters exhibited significant associations with lymphatic or neural infiltration. Significant differences in volumetric parameters, such as the MTV and TLG, were detected between the operable and non-operable subgroups. CONCLUSIONS: Metabolic (18)F-FDG PET/CT-derived parameters, such as SUVmax, SUVpeak, and the TBR, are useful for predicting venous infiltration status in patients with operable pancreatic adenocarcinoma.