Abdominal US for diagnosis of pancreatic tumor: prospective cohort analysis.

Abstract

To elucidate the accuracy of abdominal ultrasonography (US) in the diagnosis of pancreatic tumors. In all patients referred for pancreatic US during 1988-1990, data on malignant disease and survival were analyzed by using the Swedish Death and Cancer Registries. Nine hundred nineteen patients were entered into the analysis. In 140 of them, a clinical diagnosis of tumor in the pancreatic area was confirmed within 1 year after US. These tumors were primary pancreatic tumors (n = 102), common bile duct and duodenal cancers (n = 17), and metastases in the pancreatic area (n = 21). The sensitivity of US in the detection of all tumors in the pancreatic area was 88.6% (124 of 140 patients), which was similar to that for the detection of exocrine pancreatic cancer, 90% (79 of 88 patients). There were nine false-positive US examinations, for a specificity of 98.8% (770 of 779 patients). Systematic sampling of 94 investigations confirmed an association between US accuracy and presence of clinical symptoms of pancreatic cancer. Significant differences in the sensitivity (P < .05) and accuracy (P < .01) of diagnosis were observed between three experienced investigators. Study results support the use of US as a first-line diagnostic examination in patients suspected of having pancreatic tumor. Dependency on the investigator's experience with US mandates continuous evaluation of its performance.