Role of FDG PET/CT scan in preoperative pancreatic cancer staging.

Abstract

511 Background: Guidelines do not recommend routine FDG PET/CT (PET) as preoperative staging for pancreatic cancer, although many single center series have demonstrated that PET can lead to changes in management in a sizable minority of patients. We performed a retrospective analysis of patients undergoing PET for potentially resectable pancreatic adenocarcinoma at our institution to help define the utility of PET in this setting. Methods: We reviewed patients with pancreatic adenocarcinoma diagnosed at our center from June 2010 to May 2017 and included patients with pancreatic adenocarcinoma felt to be potentially resectable following standard staging studies [computed tomography (CT), magnetic resonance imaging (MRI) and endoscopic ultrasound (EUS)] who also underwent preoperative PET. Data collected and analyzed included: demographics, pre-PET staging, CA19-9 levels, PET results and surgical outcomes. Results: Forty eight patients with pancreatic adenocarcinoma felt to be surgically resectable underwent PET. PET changed management in 4/48 (8.3%) of these patients. In all 4 of these patients, hepatic metastatic disease was detected on PET and planned surgery was canceled; metastatic disease was confirmed by biopsy in 1 of these patients. 1/48 (2.1%) of patients had a false positive PET scan, where a focus of suspected metastatic disease on PET was biopsied and found to be benign, allowing the patient to proceed to surgery. 3/48 (6.3%) of patients had a false negative PET; 2 patients had hepatic metastatic disease and one had peritoneal disease discovered during surgery. Mean time from negative PET to surgery in these 3 patients was 31 days (range 21-45). Degree of CA19-9 elevation and primary tumor FDG avidity did not correlate with detection of metastatic disease on PET. Conclusions: PET changed management in a smaller number of patients in this cohort than in many previously reported series with a nearly equal number of patients with false negative PET results proceeding to unnecessary surgery. These results are consistent with the currently uncertain role of PET in preoperative staging for pancreatic cancer and further work must be undertaken to optimize presurgical staging in this population.