Utility of PET/CT as initial staging work up for early pancreatic cancer.

Abstract

183 Background: In pancreatic cancer, early detection and complete surgical resection with negative margins offers the only cure for the disease. Work up to evaluate resectability includes triple phase helical scan CT of the pancreas and endoscopic ultrasound (EUS). A paucity of data exists in using PET/CT scan as staging work up in early resectable pancreatic cancer. The objective of our study was to determine if PET/CT prevents futile laparotomy by detecting occult metastatic disease in patients with resectable/borderline pancreatic cancer. Methods: We looked at our institutional PET/CT data base incorporating National Oncologic PET Registry (NOPR) with diagnosis of resectable or borderline pancreatic cancer from 2005-2012. Clinical, radiographic, and pathologic follow-up was evaluated, including age, gender, evidence of metastatic disease, and initial CA 19–9 levels. The impact of PET/CT on patient management was estimated by calculating the percentage of patients whose treatment plan was altered due to PET/CT. The confidence interval was computed using the exact binomial distribution. The effect on the change was evaluated by the multiple logistic regression model. The final model was selected using the backward elimination method. Results: 287 patients with early stage (resectable or borderline) pancreatic cancer who received PET/CT as part of initial staging workup were identified. Upon initial work up (CT + EUS), 62% of patients were considered resectable and 38% were borderline resectable. However, PET/CT findings changed the management in 11.9% (n=34) of patients (95% CI: 0.084 – 0.162). 33 patients were upstaged to stage IV and 1 patient was upstaged to stage III. Median time from CT to PET/CT was 5 days. Metastatic lesions were confirmed with biopsy in 21 patients. The proportion in the change in treatment plan is significantly higher in patients who were borderline resectable (p=0.005; OR=2.94; 95% CI: 1.38 – 6.26). In 204 patients who were taken to surgery, 17.7% (n=36) were found to have metastatic disease intraoperatively. Conclusions: PET/CT helped improve detection of occult metastases, ultimately sparing these patients a potentially unnecessary operation. The role of PET/CT scan should be validated in prospective study.