Utility of [18F] flourodeoxyglucose positron emission tomography (FDG-PET) to predict resectability after neoadjuvant therapy in patients with unresectable pancreatic cancer on CT scans.
357 Background: The standard imaging approach in patients with pancreatic cancer is contrast enhanced computed tomography (CT), however, Response Evaluation Criteria in Solid Tumors (RECIST) may not be adequate in evaluating response to neoadjuvant therapy. A growing body of evidence exists to suggest that there is additional useful information to be gained from the use of FDG-PET scans in this setting. Methods: We conducted an IRB approved retrospective chart review of patients with locally advanced or borderline resectable pancreatic adenocarcinoma who underwent neoadjuvant therapy at the University of Oklahoma and who had PET/CT imaging before and/or after neoadjuvant therapy between September 2006 and September 2013. Complete remission (CR) was defined as decrease in SUV to ≤ 3.0 or background, and partial response (PR) was defined as decrease in SUV from baseline, but > 3.0. Results: A total of 13 patients underwent Whipple surgery after neoadjuvant therapy at our institution. Four patients (31%) had persistent unresectable disease on CT scans post-neoadjuvant therapy, but demonstrated CR (three patients) or PR (one patient; Pre-treatment SUV: 10.1, Post Treatment: 4.6) on the PET scan. These patients underwent Whipple surgery based on PET response. All four (100%) patients underwent R0 resection. Two patients (50%) received neoadjuvant chemo-radiation in addition to chemotherapy. Conclusions: Response on FDG-PET/CT can be a predictor of R0 resection in cases with evidence of unresectable disease on conventional CT scan. A protocol to study larger number of patients prospectively is being designed.