Diagnosis and staging of pancreatic cancer by positron emission tomography

The detection of pancreatic cancer or the discrimination between pancreatic cancer and chronic pancreatitis remains an important diagnostic problem. S everal imaging modalities are now used to diagnose pancreatic cancer, inclu ding transabdominal ultrasonography (US), contrast-enhanced computed tomogr aphy (CT), magnetic resonance imaging (MRI), endoscopic retrograde cholangi opancreatography (ERCP), endoscopic ultrasonography, and selective angiogra phy. None of these six methods is perfect: Each has advantages and disadvan tages, and their sensitivity and specificity are in a high range. In 1990 p ositron emission tomography (PET) was first applied to diagnose pancreatic cancer. This new diagnostic modality is based on functional changes in the pancreatic cancer cells caused by enhanced glucose metabolism. Increased gl ucose utilization is one of the characteristics of malignantly transformed cells, independent of their origin. The technical development of PET has al lowed this new procedure to be used for clinical evaluation. Using 2-(F-18) -fluoro-2-deoxy-D-glucose, PET can identify pancreatic cancer and different iate pancreatic cancer from chronic pancreatitis with a sensitivity of 85% to 98% and a specificity of 53% to 93%. However, high sensitivity and high specificity are strongly dependent on the tumor stage. At present PET is st ill experimental and is available only in specialized centers. It may repre sent a new and noninvasive diagnostic procedure for the detection and the s taging of pancreatic cancer. Further clinical studies, especially including patients with early tumor stages (small tumor size), are needed. This revi ew discusses the possibilities and limits of PET and evaluates its importan ce in the future.