Usefulness of FDG-PET in predicting the prognosis of advanced pancreatic carcinoma with chemotherapy

Abstract

14043 Background: 18F-fluorodeoxyglucose (FDG) PET is a new diagnostic imaging technique that takes advantage of increased glucose metabolism by the tumor cells. High uptake of FDG is reportedly associated with poor survival in head and neck cancer (Heikki et al., 1997, Nuclear Oncology). FDG uptake diminishes with elevated levels of plasma glucose. We herein evaluated the usefulness of FDG-PET in predicting the prognosis of advanced pancreatic carcinoma (APC). Methods: FDG-PET was performed on 32 consecutive patients with APC between July 2001 and April 2004. The patients fasted for at least 5 hr before the study. The plasma glucose level was controlled under 150 mg/dl by using oral antidiabetic or insulin therapy in advance. FDG-PET images were acquired 45 min after intravenous injection of FDG. We did not measure the plasma glucose level directly before imaging. The FDG uptake in the primary tumor was quantitated as the standardized uptake value (SUV), and the maximum SUV (SUVmax) was measured in the regions of interest. All of the 32 APC patients received chemotherapy (26: gemcitabine, 1: gemcitabine + UFT, 5: TS-1). We analyzed the correlation between SUVmax and the overall survival. Then, we excluded the diabetics (n = 8) and compared SUV in the non-diabetic patients (n = 24). The overall survival curve was plotted according to the method of Kaplan and Meier. The difference in the overall survival was calculated using the log-rank test, and a multivariate analysis was conducted. Results: 32 patients were examined. All cases showed FDG uptake in the pancreatic tumor (SUVmax ranged from 2.73 to 9.67). The overall survival ranged from 38 to 945 days with a median of 261 days.These patients were classified into two groups at a median SUVmax value of 4.81. There was no significant difference in the overall survival between these two groups (p > 0.05). The non-diabetic patients (n = 24) were classified into two groups at a median SUVmax value of 5.51. The high SUVmax group had shorter overall survival than the low SUVmax group (p = 0.039). The multivariate analysis using Cox hazard model also revealed that SUVmax was a significant, independent factor that influenced the survival (p = 0.043) in the non-diabetic patients. Conclusions: FDG-PET may be a useful modality in determining the prognosis of APC. No significant financial relationships to disclose.