P-P46 The use of FDG-PET/CT in the pre-operative staging of pancreatic ductal adenocarcinoma

Abstract

Abstract Background The NICE Quality Standard for Pancreatic Cancer (December 2018) recommends that ‘adults with localised pancreatic cancer on CT(should) have staging using fluorodeoxyglucose positron emission tomography/CT(FDG-PET/CT) before they have surgery, radiotherapy or systemic therapy’. Such FDG-PET/CT staging aims to provide additional information to conventional cross-sectional imaging, thus presenting the most accurate staging of disease. However, the sensitivity and specificity of FDG-PET/CT to deliver relevant additional clinical information must be balanced with potential delays to treatment, and additional cost associated with its use, in the management of a time-critical pathology. Methods Consecutive pancreatic ductal adenocarcinoma(PDAC) patients deemed resectable on conventional imaging, and therefore referred for FDG-PET/CT assessment, were included for analysis. Data were derived from a single tertiary Hepatopancreaticobiliary(HPB) centre between May 2018 and June 2021. Data were collected and analysed from a combination of prospectively-collated electronic databases and paper patient records. Results Of 89 patients analysed, 55(61.7%) patients were male. Primary pancreatic lesions were PET avid in 81 cases(91%). Median time from request to FDG-PET/CT performance was 11 days(Range 1-35). Additional clinical information from FDG-PET/CT was provided in 61(68.5%) patients. Further investigations to assess FDG-PET/CT findings were arranged in 23 patients(25.8%; including liver MRI and EUS), demonstrating that FDG-PET/CT findings were true-positive in 6(26.1%), false-positive in 15(65.2%) and equivocal in 2(8.7%). There was a median delay of 60.5 days(Range 26 to 256) from FDG-PET/CT to surgery in those undergoing additional investigation. In total, a new diagnosis of metastatic/non-resectable disease was made in 14(15.7%) patients, preventing progression to planned operative intervention. Conclusions FDG-PET/CT provided additional information to conventional imaging that led to cancellation of planned operative resection in 14(15.7%) PDAC patients-8 directly and 6 following further investigation. However, there was a median delay of 11 days to FDG-PET/CT and 60.5 days from FDG-PET/CT to surgery in those undergoing additional investigation. Whilst FDG-PET/CT can lead to avoidance of unnecessary surgical intervention in PDAC patients with unsuspected metastatic/non-resectable disease, it can lead to delay, over-investigation, excess cost and anxiety in resectable patients. HPB units should audit their own findings to assess whether the use of FDG-PET/CT should be considered on a standard or selected basis.