18F-fluoro-2-deoxy-D-glucose retention index as a prognostic parameter in patients with pancreatic cancer

The objective of this study was to determine the most effective way to use dual-phase F-fluoro-2-deoxy-D-glucose (F-FDG) PET/computed tomography (CT) semiquantitative indices to predict prognosis in patients with pancreatic cancer and to guide treatment.

Prognostic parameters were retrospectively analyzed in 40 patients with histologically proven pancreatic cancer who received F-FDG PET/CT at Ruijin Hospital. Maximum standardized uptake values (SUVs) were determined at 1 h (SUV1) and 2 h (SUV2) after F-FDG injection. The retention index (RI) was defined as the percentage change between SUV1 and SUV2.

RI less than 17% was explored as having a significant independent correlation with prolonged patient survival (P<0.05). Patients with tumor resection and RI less than 17% survived significantly longer than those with or without tumor resection and RI of 17% or higher (P<0.05). Neither SUV1, nor SUV2 showed any prognostic significance, but they did show a positive correlation with tumor diameter (P1<0.01; P2<0.05); RI had a strong positive correlation with tumor, node, and metastasis stage (P<0.01). Two factors were found to be associated with RI, including pancreatitis (P<0.05) and diabetes (P<0.01).

RI served as the most accurate parameter to predict disease prognosis in pancreatic cancer and to identify patients who could benefit from surgery. However, pancreatitis and diabetes had a potential impact on RI, reflecting the influence of tumor pathophysiological changes on the metabolism of glucose in pancreatic tumor cells. Therefore, further comprehensive analyses are required.